diff options
Diffstat (limited to 'arch/parisc/math-emu/fmpyfadd.c')
| -rw-r--r-- | arch/parisc/math-emu/fmpyfadd.c | 2655 |
1 files changed, 2655 insertions, 0 deletions
diff --git a/arch/parisc/math-emu/fmpyfadd.c b/arch/parisc/math-emu/fmpyfadd.c new file mode 100644 index 000000000000..5dd7f93a89be --- /dev/null +++ b/arch/parisc/math-emu/fmpyfadd.c @@ -0,0 +1,2655 @@ +/* + * Linux/PA-RISC Project (http://www.parisc-linux.org/) + * + * Floating-point emulation code + * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2, or (at your option) + * any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +/* + * BEGIN_DESC + * + * File: + * @(#) pa/spmath/fmpyfadd.c $Revision: 1.1 $ + * + * Purpose: + * Double Floating-point Multiply Fused Add + * Double Floating-point Multiply Negate Fused Add + * Single Floating-point Multiply Fused Add + * Single Floating-point Multiply Negate Fused Add + * + * External Interfaces: + * dbl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr) + * dbl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) + * sgl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr) + * sgl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) + * + * Internal Interfaces: + * + * Theory: + * <<please update with a overview of the operation of this file>> + * + * END_DESC +*/ + + +#include "float.h" +#include "sgl_float.h" +#include "dbl_float.h" + + +/* + * Double Floating-point Multiply Fused Add + */ + +int +dbl_fmpyfadd( + dbl_floating_point *src1ptr, + dbl_floating_point *src2ptr, + dbl_floating_point *src3ptr, + unsigned int *status, + dbl_floating_point *dstptr) +{ + unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2, opnd3p1, opnd3p2; + register unsigned int tmpresp1, tmpresp2, tmpresp3, tmpresp4; + unsigned int rightp1, rightp2, rightp3, rightp4; + unsigned int resultp1, resultp2 = 0, resultp3 = 0, resultp4 = 0; + register int mpy_exponent, add_exponent, count; + boolean inexact = FALSE, is_tiny = FALSE; + + unsigned int signlessleft1, signlessright1, save; + register int result_exponent, diff_exponent; + int sign_save, jumpsize; + + Dbl_copyfromptr(src1ptr,opnd1p1,opnd1p2); + Dbl_copyfromptr(src2ptr,opnd2p1,opnd2p2); + Dbl_copyfromptr(src3ptr,opnd3p1,opnd3p2); + + /* + * set sign bit of result of multiply + */ + if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) + Dbl_setnegativezerop1(resultp1); + else Dbl_setzerop1(resultp1); + + /* + * Generate multiply exponent + */ + mpy_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) - DBL_BIAS; + + /* + * check first operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd1p1)) { + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + if (Dbl_isnotnan(opnd2p1,opnd2p2) && + Dbl_isnotnan(opnd3p1,opnd3p2)) { + if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { + /* + * invalid since operands are infinity + * and zero + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Dbl_isinfinity(opnd3p1,opnd3p2) && + (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Dbl_setinfinity_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd1p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd1p1); + } + /* + * is second operand a signaling NaN? + */ + else if (Dbl_is_signalingnan(opnd2p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd2p1); + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + /* + * is third operand a signaling NaN? + */ + else if (Dbl_is_signalingnan(opnd3p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd3p1); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check second operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd2p1)) { + if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { + if (Dbl_isnotnan(opnd3p1,opnd3p2)) { + if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) { + /* + * invalid since multiply operands are + * zero & infinity + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(opnd2p1,opnd2p2); + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Dbl_isinfinity(opnd3p1,opnd3p2) && + (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Dbl_setinfinity_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd2p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd2p1); + } + /* + * is third operand a signaling NaN? + */ + else if (Dbl_is_signalingnan(opnd3p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd3p1); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check third operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd3p1)) { + if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { + /* return infinity */ + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } else { + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd3p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd3p1); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * Generate multiply mantissa + */ + if (Dbl_isnotzero_exponent(opnd1p1)) { + /* set hidden bit */ + Dbl_clear_signexponent_set_hidden(opnd1p1); + } + else { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Dbl_or_signs(opnd3p1,resultp1); + } else { + Dbl_and_signs(opnd3p1,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Dbl_iszero_exponent(opnd3p1) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Dbl_signextendedsign(opnd3p1); + result_exponent = 0; + Dbl_leftshiftby1(opnd3p1,opnd3p2); + Dbl_normalize(opnd3p1,opnd3p2,result_exponent); + Dbl_set_sign(opnd3p1,/*using*/sign_save); + Dbl_setwrapped_exponent(opnd3p1,result_exponent, + unfl); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* is denormalized, adjust exponent */ + Dbl_clear_signexponent(opnd1p1); + Dbl_leftshiftby1(opnd1p1,opnd1p2); + Dbl_normalize(opnd1p1,opnd1p2,mpy_exponent); + } + /* opnd2 needs to have hidden bit set with msb in hidden bit */ + if (Dbl_isnotzero_exponent(opnd2p1)) { + Dbl_clear_signexponent_set_hidden(opnd2p1); + } + else { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Dbl_or_signs(opnd3p1,resultp1); + } else { + Dbl_and_signs(opnd3p1,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Dbl_iszero_exponent(opnd3p1) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Dbl_signextendedsign(opnd3p1); + result_exponent = 0; + Dbl_leftshiftby1(opnd3p1,opnd3p2); + Dbl_normalize(opnd3p1,opnd3p2,result_exponent); + Dbl_set_sign(opnd3p1,/*using*/sign_save); + Dbl_setwrapped_exponent(opnd3p1,result_exponent, + unfl); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* is denormalized; want to normalize */ + Dbl_clear_signexponent(opnd2p1); + Dbl_leftshiftby1(opnd2p1,opnd2p2); + Dbl_normalize(opnd2p1,opnd2p2,mpy_exponent); + } + + /* Multiply the first two source mantissas together */ + + /* + * The intermediate result will be kept in tmpres, + * which needs enough room for 106 bits of mantissa, + * so lets call it a Double extended. + */ + Dblext_setzero(tmpresp1,tmpresp2,tmpresp3,tmpresp4); + + /* + * Four bits at a time are inspected in each loop, and a + * simple shift and add multiply algorithm is used. + */ + for (count = DBL_P-1; count >= 0; count -= 4) { + Dblext_rightshiftby4(tmpresp1,tmpresp2,tmpresp3,tmpresp4); + if (Dbit28p2(opnd1p2)) { + /* Fourword_add should be an ADD followed by 3 ADDC's */ + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1<<3 | opnd2p2>>29, opnd2p2<<3, 0, 0); + } + if (Dbit29p2(opnd1p2)) { + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1<<2 | opnd2p2>>30, opnd2p2<<2, 0, 0); + } + if (Dbit30p2(opnd1p2)) { + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1<<1 | opnd2p2>>31, opnd2p2<<1, 0, 0); + } + if (Dbit31p2(opnd1p2)) { + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1, opnd2p2, 0, 0); + } + Dbl_rightshiftby4(opnd1p1,opnd1p2); + } + if (Is_dexthiddenoverflow(tmpresp1)) { + /* result mantissa >= 2 (mantissa overflow) */ + mpy_exponent++; + Dblext_rightshiftby1(tmpresp1,tmpresp2,tmpresp3,tmpresp4); + } + + /* + * Restore the sign of the mpy result which was saved in resultp1. + * The exponent will continue to be kept in mpy_exponent. + */ + Dblext_set_sign(tmpresp1,Dbl_sign(resultp1)); + + /* + * No rounding is required, since the result of the multiply + * is exact in the extended format. + */ + + /* + * Now we are ready to perform the add portion of the operation. + * + * The exponents need to be kept as integers for now, since the + * multiply result might not fit into the exponent field. We + * can't overflow or underflow because of this yet, since the + * add could bring the final result back into range. + */ + add_exponent = Dbl_exponent(opnd3p1); + + /* + * Check for denormalized or zero add operand. + */ + if (add_exponent == 0) { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { + /* right is zero */ + /* Left can't be zero and must be result. + * + * The final result is now in tmpres and mpy_exponent, + * and needs to be rounded and squeezed back into + * double precision format from double extended. + */ + result_exponent = mpy_exponent; + Dblext_copy(tmpresp1,tmpresp2,tmpresp3,tmpresp4, + resultp1,resultp2,resultp3,resultp4); + sign_save = Dbl_signextendedsign(resultp1);/*save sign*/ + goto round; + } + + /* + * Neither are zeroes. + * Adjust exponent and normalize add operand. + */ + sign_save = Dbl_signextendedsign(opnd3p1); /* save sign */ + Dbl_clear_signexponent(opnd3p1); + Dbl_leftshiftby1(opnd3p1,opnd3p2); + Dbl_normalize(opnd3p1,opnd3p2,add_exponent); + Dbl_set_sign(opnd3p1,sign_save); /* restore sign */ + } else { + Dbl_clear_exponent_set_hidden(opnd3p1); + } + /* + * Copy opnd3 to the double extended variable called right. + */ + Dbl_copyto_dblext(opnd3p1,opnd3p2,rightp1,rightp2,rightp3,rightp4); + + /* + * A zero "save" helps discover equal operands (for later), + * and is used in swapping operands (if needed). + */ + Dblext_xortointp1(tmpresp1,rightp1,/*to*/save); + + /* + * Compare magnitude of operands. + */ + Dblext_copytoint_exponentmantissap1(tmpresp1,signlessleft1); + Dblext_copytoint_exponentmantissap1(rightp1,signlessright1); + if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && + Dblext_ismagnitudeless(tmpresp2,rightp2,signlessleft1,signlessright1)){ + /* + * Set the left operand to the larger one by XOR swap. + * First finish the first word "save". + */ + Dblext_xorfromintp1(save,rightp1,/*to*/rightp1); + Dblext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); + Dblext_swap_lower(tmpresp2,tmpresp3,tmpresp4, + rightp2,rightp3,rightp4); + /* also setup exponents used in rest of routine */ + diff_exponent = add_exponent - mpy_exponent; + result_exponent = add_exponent; + } else { + /* also setup exponents used in rest of routine */ + diff_exponent = mpy_exponent - add_exponent; + result_exponent = mpy_exponent; + } + /* Invariant: left is not smaller than right. */ + + /* + * Special case alignment of operands that would force alignment + * beyond the extent of the extension. A further optimization + * could special case this but only reduces the path length for + * this infrequent case. + */ + if (diff_exponent > DBLEXT_THRESHOLD) { + diff_exponent = DBLEXT_THRESHOLD; + } + + /* Align right operand by shifting it to the right */ + Dblext_clear_sign(rightp1); + Dblext_right_align(rightp1,rightp2,rightp3,rightp4, + /*shifted by*/diff_exponent); + + /* Treat sum and difference of the operands separately. */ + if ((int)save < 0) { + /* + * Difference of the two operands. Overflow can occur if the + * multiply overflowed. A borrow can occur out of the hidden + * bit and force a post normalization phase. + */ + Dblext_subtract(tmpresp1,tmpresp2,tmpresp3,tmpresp4, + rightp1,rightp2,rightp3,rightp4, + resultp1,resultp2,resultp3,resultp4); + sign_save = Dbl_signextendedsign(resultp1); + if (Dbl_iszero_hidden(resultp1)) { + /* Handle normalization */ + /* A straight foward algorithm would now shift the + * result and extension left until the hidden bit + * becomes one. Not all of the extension bits need + * participate in the shift. Only the two most + * significant bits (round and guard) are needed. + * If only a single shift is needed then the guard + * bit becomes a significant low order bit and the + * extension must participate in the rounding. + * If more than a single shift is needed, then all + * bits to the right of the guard bit are zeros, + * and the guard bit may or may not be zero. */ + Dblext_leftshiftby1(resultp1,resultp2,resultp3, + resultp4); + + /* Need to check for a zero result. The sign and + * exponent fields have already been zeroed. The more + * efficient test of the full object can be used. + */ + if(Dblext_iszero(resultp1,resultp2,resultp3,resultp4)){ + /* Must have been "x-x" or "x+(-x)". */ + if (Is_rounding_mode(ROUNDMINUS)) + Dbl_setone_sign(resultp1); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + result_exponent--; + + /* Look to see if normalization is finished. */ + if (Dbl_isone_hidden(resultp1)) { + /* No further normalization is needed */ + goto round; + } + + /* Discover first one bit to determine shift amount. + * Use a modified binary search. We have already + * shifted the result one position right and still + * not found a one so the remainder of the extension + * must be zero and simplifies rounding. */ + /* Scan bytes */ + while (Dbl_iszero_hiddenhigh7mantissa(resultp1)) { + Dblext_leftshiftby8(resultp1,resultp2,resultp3,resultp4); + result_exponent -= 8; + } + /* Now narrow it down to the nibble */ + if (Dbl_iszero_hiddenhigh3mantissa(resultp1)) { + /* The lower nibble contains the + * normalizing one */ + Dblext_leftshiftby4(resultp1,resultp2,resultp3,resultp4); + result_exponent -= 4; + } + /* Select case where first bit is set (already + * normalized) otherwise select the proper shift. */ + jumpsize = Dbl_hiddenhigh3mantissa(resultp1); + if (jumpsize <= 7) switch(jumpsize) { + case 1: + Dblext_leftshiftby3(resultp1,resultp2,resultp3, + resultp4); + result_exponent -= 3; + break; + case 2: + case 3: + Dblext_leftshiftby2(resultp1,resultp2,resultp3, + resultp4); + result_exponent -= 2; + break; + case 4: + case 5: + case 6: + case 7: + Dblext_leftshiftby1(resultp1,resultp2,resultp3, + resultp4); + result_exponent -= 1; + break; + } + } /* end if (hidden...)... */ + /* Fall through and round */ + } /* end if (save < 0)... */ + else { + /* Add magnitudes */ + Dblext_addition(tmpresp1,tmpresp2,tmpresp3,tmpresp4, + rightp1,rightp2,rightp3,rightp4, + /*to*/resultp1,resultp2,resultp3,resultp4); + sign_save = Dbl_signextendedsign(resultp1); + if (Dbl_isone_hiddenoverflow(resultp1)) { + /* Prenormalization required. */ + Dblext_arithrightshiftby1(resultp1,resultp2,resultp3, + resultp4); + result_exponent++; + } /* end if hiddenoverflow... */ + } /* end else ...add magnitudes... */ + + /* Round the result. If the extension and lower two words are + * all zeros, then the result is exact. Otherwise round in the + * correct direction. Underflow is possible. If a postnormalization + * is necessary, then the mantissa is all zeros so no shift is needed. + */ + round: + if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { + Dblext_denormalize(resultp1,resultp2,resultp3,resultp4, + result_exponent,is_tiny); + } + Dbl_set_sign(resultp1,/*using*/sign_save); + if (Dblext_isnotzero_mantissap3(resultp3) || + Dblext_isnotzero_mantissap4(resultp4)) { + inexact = TRUE; + switch(Rounding_mode()) { + case ROUNDNEAREST: /* The default. */ + if (Dblext_isone_highp3(resultp3)) { + /* at least 1/2 ulp */ + if (Dblext_isnotzero_low31p3(resultp3) || + Dblext_isnotzero_mantissap4(resultp4) || + Dblext_isone_lowp2(resultp2)) { + /* either exactly half way and odd or + * more than 1/2ulp */ + Dbl_increment(resultp1,resultp2); + } + } + break; + + case ROUNDPLUS: + if (Dbl_iszero_sign(resultp1)) { + /* Round up positive results */ + Dbl_increment(resultp1,resultp2); + } + break; + + case ROUNDMINUS: + if (Dbl_isone_sign(resultp1)) { + /* Round down negative results */ + Dbl_increment(resultp1,resultp2); + } + + case ROUNDZERO:; + /* truncate is simple */ + } /* end switch... */ + if (Dbl_isone_hiddenoverflow(resultp1)) result_exponent++; + } + if (result_exponent >= DBL_INFINITY_EXPONENT) { + /* trap if OVERFLOWTRAP enabled */ + if (Is_overflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_OVERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return (OPC_2E_OVERFLOWEXCEPTION); + } + inexact = TRUE; + Set_overflowflag(); + /* set result to infinity or largest number */ + Dbl_setoverflow(resultp1,resultp2); + + } else if (result_exponent <= 0) { /* underflow case */ + if (Is_underflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Dbl_setwrapped_exponent(resultp1,result_exponent,unfl); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_UNDERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(OPC_2E_UNDERFLOWEXCEPTION); + } + else if (inexact && is_tiny) Set_underflowflag(); + } + else Dbl_set_exponent(resultp1,result_exponent); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(NOEXCEPTION); +} + +/* + * Double Floating-point Multiply Negate Fused Add + */ + +dbl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) + +dbl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr; +unsigned int *status; +{ + unsigned int opnd1p1, opnd1p2, opnd2p1, opnd2p2, opnd3p1, opnd3p2; + register unsigned int tmpresp1, tmpresp2, tmpresp3, tmpresp4; + unsigned int rightp1, rightp2, rightp3, rightp4; + unsigned int resultp1, resultp2 = 0, resultp3 = 0, resultp4 = 0; + register int mpy_exponent, add_exponent, count; + boolean inexact = FALSE, is_tiny = FALSE; + + unsigned int signlessleft1, signlessright1, save; + register int result_exponent, diff_exponent; + int sign_save, jumpsize; + + Dbl_copyfromptr(src1ptr,opnd1p1,opnd1p2); + Dbl_copyfromptr(src2ptr,opnd2p1,opnd2p2); + Dbl_copyfromptr(src3ptr,opnd3p1,opnd3p2); + + /* + * set sign bit of result of multiply + */ + if (Dbl_sign(opnd1p1) ^ Dbl_sign(opnd2p1)) + Dbl_setzerop1(resultp1); + else + Dbl_setnegativezerop1(resultp1); + + /* + * Generate multiply exponent + */ + mpy_exponent = Dbl_exponent(opnd1p1) + Dbl_exponent(opnd2p1) - DBL_BIAS; + + /* + * check first operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd1p1)) { + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + if (Dbl_isnotnan(opnd2p1,opnd2p2) && + Dbl_isnotnan(opnd3p1,opnd3p2)) { + if (Dbl_iszero_exponentmantissa(opnd2p1,opnd2p2)) { + /* + * invalid since operands are infinity + * and zero + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Dbl_isinfinity(opnd3p1,opnd3p2) && + (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Dbl_setinfinity_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd1p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd1p1); + } + /* + * is second operand a signaling NaN? + */ + else if (Dbl_is_signalingnan(opnd2p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd2p1); + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + /* + * is third operand a signaling NaN? + */ + else if (Dbl_is_signalingnan(opnd3p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd3p1); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd1p1,opnd1p2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check second operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd2p1)) { + if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { + if (Dbl_isnotnan(opnd3p1,opnd3p2)) { + if (Dbl_iszero_exponentmantissa(opnd1p1,opnd1p2)) { + /* + * invalid since multiply operands are + * zero & infinity + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(opnd2p1,opnd2p2); + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Dbl_isinfinity(opnd3p1,opnd3p2) && + (Dbl_sign(resultp1) ^ Dbl_sign(opnd3p1))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Dbl_makequietnan(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Dbl_setinfinity_exponentmantissa(resultp1,resultp2); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd2p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd2p1); + } + /* + * is third operand a signaling NaN? + */ + else if (Dbl_is_signalingnan(opnd3p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd3p1); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd2p1,opnd2p2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check third operand for NaN's or infinity + */ + if (Dbl_isinfinity_exponent(opnd3p1)) { + if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { + /* return infinity */ + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } else { + /* + * is NaN; signaling or quiet? + */ + if (Dbl_isone_signaling(opnd3p1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Dbl_set_quiet(opnd3p1); + } + /* + * return quiet NaN + */ + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * Generate multiply mantissa + */ + if (Dbl_isnotzero_exponent(opnd1p1)) { + /* set hidden bit */ + Dbl_clear_signexponent_set_hidden(opnd1p1); + } + else { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd1p1,opnd1p2)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Dbl_or_signs(opnd3p1,resultp1); + } else { + Dbl_and_signs(opnd3p1,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Dbl_iszero_exponent(opnd3p1) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Dbl_signextendedsign(opnd3p1); + result_exponent = 0; + Dbl_leftshiftby1(opnd3p1,opnd3p2); + Dbl_normalize(opnd3p1,opnd3p2,result_exponent); + Dbl_set_sign(opnd3p1,/*using*/sign_save); + Dbl_setwrapped_exponent(opnd3p1,result_exponent, + unfl); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* is denormalized, adjust exponent */ + Dbl_clear_signexponent(opnd1p1); + Dbl_leftshiftby1(opnd1p1,opnd1p2); + Dbl_normalize(opnd1p1,opnd1p2,mpy_exponent); + } + /* opnd2 needs to have hidden bit set with msb in hidden bit */ + if (Dbl_isnotzero_exponent(opnd2p1)) { + Dbl_clear_signexponent_set_hidden(opnd2p1); + } + else { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd2p1,opnd2p2)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Dbl_iszero_exponentmantissa(opnd3p1,opnd3p2)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Dbl_or_signs(opnd3p1,resultp1); + } else { + Dbl_and_signs(opnd3p1,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Dbl_iszero_exponent(opnd3p1) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Dbl_signextendedsign(opnd3p1); + result_exponent = 0; + Dbl_leftshiftby1(opnd3p1,opnd3p2); + Dbl_normalize(opnd3p1,opnd3p2,result_exponent); + Dbl_set_sign(opnd3p1,/*using*/sign_save); + Dbl_setwrapped_exponent(opnd3p1,result_exponent, + unfl); + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Dbl_copytoptr(opnd3p1,opnd3p2,dstptr); + return(NOEXCEPTION); + } + /* is denormalized; want to normalize */ + Dbl_clear_signexponent(opnd2p1); + Dbl_leftshiftby1(opnd2p1,opnd2p2); + Dbl_normalize(opnd2p1,opnd2p2,mpy_exponent); + } + + /* Multiply the first two source mantissas together */ + + /* + * The intermediate result will be kept in tmpres, + * which needs enough room for 106 bits of mantissa, + * so lets call it a Double extended. + */ + Dblext_setzero(tmpresp1,tmpresp2,tmpresp3,tmpresp4); + + /* + * Four bits at a time are inspected in each loop, and a + * simple shift and add multiply algorithm is used. + */ + for (count = DBL_P-1; count >= 0; count -= 4) { + Dblext_rightshiftby4(tmpresp1,tmpresp2,tmpresp3,tmpresp4); + if (Dbit28p2(opnd1p2)) { + /* Fourword_add should be an ADD followed by 3 ADDC's */ + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1<<3 | opnd2p2>>29, opnd2p2<<3, 0, 0); + } + if (Dbit29p2(opnd1p2)) { + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1<<2 | opnd2p2>>30, opnd2p2<<2, 0, 0); + } + if (Dbit30p2(opnd1p2)) { + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1<<1 | opnd2p2>>31, opnd2p2<<1, 0, 0); + } + if (Dbit31p2(opnd1p2)) { + Fourword_add(tmpresp1, tmpresp2, tmpresp3, tmpresp4, + opnd2p1, opnd2p2, 0, 0); + } + Dbl_rightshiftby4(opnd1p1,opnd1p2); + } + if (Is_dexthiddenoverflow(tmpresp1)) { + /* result mantissa >= 2 (mantissa overflow) */ + mpy_exponent++; + Dblext_rightshiftby1(tmpresp1,tmpresp2,tmpresp3,tmpresp4); + } + + /* + * Restore the sign of the mpy result which was saved in resultp1. + * The exponent will continue to be kept in mpy_exponent. + */ + Dblext_set_sign(tmpresp1,Dbl_sign(resultp1)); + + /* + * No rounding is required, since the result of the multiply + * is exact in the extended format. + */ + + /* + * Now we are ready to perform the add portion of the operation. + * + * The exponents need to be kept as integers for now, since the + * multiply result might not fit into the exponent field. We + * can't overflow or underflow because of this yet, since the + * add could bring the final result back into range. + */ + add_exponent = Dbl_exponent(opnd3p1); + + /* + * Check for denormalized or zero add operand. + */ + if (add_exponent == 0) { + /* check for zero */ + if (Dbl_iszero_mantissa(opnd3p1,opnd3p2)) { + /* right is zero */ + /* Left can't be zero and must be result. + * + * The final result is now in tmpres and mpy_exponent, + * and needs to be rounded and squeezed back into + * double precision format from double extended. + */ + result_exponent = mpy_exponent; + Dblext_copy(tmpresp1,tmpresp2,tmpresp3,tmpresp4, + resultp1,resultp2,resultp3,resultp4); + sign_save = Dbl_signextendedsign(resultp1);/*save sign*/ + goto round; + } + + /* + * Neither are zeroes. + * Adjust exponent and normalize add operand. + */ + sign_save = Dbl_signextendedsign(opnd3p1); /* save sign */ + Dbl_clear_signexponent(opnd3p1); + Dbl_leftshiftby1(opnd3p1,opnd3p2); + Dbl_normalize(opnd3p1,opnd3p2,add_exponent); + Dbl_set_sign(opnd3p1,sign_save); /* restore sign */ + } else { + Dbl_clear_exponent_set_hidden(opnd3p1); + } + /* + * Copy opnd3 to the double extended variable called right. + */ + Dbl_copyto_dblext(opnd3p1,opnd3p2,rightp1,rightp2,rightp3,rightp4); + + /* + * A zero "save" helps discover equal operands (for later), + * and is used in swapping operands (if needed). + */ + Dblext_xortointp1(tmpresp1,rightp1,/*to*/save); + + /* + * Compare magnitude of operands. + */ + Dblext_copytoint_exponentmantissap1(tmpresp1,signlessleft1); + Dblext_copytoint_exponentmantissap1(rightp1,signlessright1); + if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && + Dblext_ismagnitudeless(tmpresp2,rightp2,signlessleft1,signlessright1)){ + /* + * Set the left operand to the larger one by XOR swap. + * First finish the first word "save". + */ + Dblext_xorfromintp1(save,rightp1,/*to*/rightp1); + Dblext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); + Dblext_swap_lower(tmpresp2,tmpresp3,tmpresp4, + rightp2,rightp3,rightp4); + /* also setup exponents used in rest of routine */ + diff_exponent = add_exponent - mpy_exponent; + result_exponent = add_exponent; + } else { + /* also setup exponents used in rest of routine */ + diff_exponent = mpy_exponent - add_exponent; + result_exponent = mpy_exponent; + } + /* Invariant: left is not smaller than right. */ + + /* + * Special case alignment of operands that would force alignment + * beyond the extent of the extension. A further optimization + * could special case this but only reduces the path length for + * this infrequent case. + */ + if (diff_exponent > DBLEXT_THRESHOLD) { + diff_exponent = DBLEXT_THRESHOLD; + } + + /* Align right operand by shifting it to the right */ + Dblext_clear_sign(rightp1); + Dblext_right_align(rightp1,rightp2,rightp3,rightp4, + /*shifted by*/diff_exponent); + + /* Treat sum and difference of the operands separately. */ + if ((int)save < 0) { + /* + * Difference of the two operands. Overflow can occur if the + * multiply overflowed. A borrow can occur out of the hidden + * bit and force a post normalization phase. + */ + Dblext_subtract(tmpresp1,tmpresp2,tmpresp3,tmpresp4, + rightp1,rightp2,rightp3,rightp4, + resultp1,resultp2,resultp3,resultp4); + sign_save = Dbl_signextendedsign(resultp1); + if (Dbl_iszero_hidden(resultp1)) { + /* Handle normalization */ + /* A straight foward algorithm would now shift the + * result and extension left until the hidden bit + * becomes one. Not all of the extension bits need + * participate in the shift. Only the two most + * significant bits (round and guard) are needed. + * If only a single shift is needed then the guard + * bit becomes a significant low order bit and the + * extension must participate in the rounding. + * If more than a single shift is needed, then all + * bits to the right of the guard bit are zeros, + * and the guard bit may or may not be zero. */ + Dblext_leftshiftby1(resultp1,resultp2,resultp3, + resultp4); + + /* Need to check for a zero result. The sign and + * exponent fields have already been zeroed. The more + * efficient test of the full object can be used. + */ + if (Dblext_iszero(resultp1,resultp2,resultp3,resultp4)) { + /* Must have been "x-x" or "x+(-x)". */ + if (Is_rounding_mode(ROUNDMINUS)) + Dbl_setone_sign(resultp1); + Dbl_copytoptr(resultp1,resultp2,dstptr); + return(NOEXCEPTION); + } + result_exponent--; + + /* Look to see if normalization is finished. */ + if (Dbl_isone_hidden(resultp1)) { + /* No further normalization is needed */ + goto round; + } + + /* Discover first one bit to determine shift amount. + * Use a modified binary search. We have already + * shifted the result one position right and still + * not found a one so the remainder of the extension + * must be zero and simplifies rounding. */ + /* Scan bytes */ + while (Dbl_iszero_hiddenhigh7mantissa(resultp1)) { + Dblext_leftshiftby8(resultp1,resultp2,resultp3,resultp4); + result_exponent -= 8; + } + /* Now narrow it down to the nibble */ + if (Dbl_iszero_hiddenhigh3mantissa(resultp1)) { + /* The lower nibble contains the + * normalizing one */ + Dblext_leftshiftby4(resultp1,resultp2,resultp3,resultp4); + result_exponent -= 4; + } + /* Select case where first bit is set (already + * normalized) otherwise select the proper shift. */ + jumpsize = Dbl_hiddenhigh3mantissa(resultp1); + if (jumpsize <= 7) switch(jumpsize) { + case 1: + Dblext_leftshiftby3(resultp1,resultp2,resultp3, + resultp4); + result_exponent -= 3; + break; + case 2: + case 3: + Dblext_leftshiftby2(resultp1,resultp2,resultp3, + resultp4); + result_exponent -= 2; + break; + case 4: + case 5: + case 6: + case 7: + Dblext_leftshiftby1(resultp1,resultp2,resultp3, + resultp4); + result_exponent -= 1; + break; + } + } /* end if (hidden...)... */ + /* Fall through and round */ + } /* end if (save < 0)... */ + else { + /* Add magnitudes */ + Dblext_addition(tmpresp1,tmpresp2,tmpresp3,tmpresp4, + rightp1,rightp2,rightp3,rightp4, + /*to*/resultp1,resultp2,resultp3,resultp4); + sign_save = Dbl_signextendedsign(resultp1); + if (Dbl_isone_hiddenoverflow(resultp1)) { + /* Prenormalization required. */ + Dblext_arithrightshiftby1(resultp1,resultp2,resultp3, + resultp4); + result_exponent++; + } /* end if hiddenoverflow... */ + } /* end else ...add magnitudes... */ + + /* Round the result. If the extension and lower two words are + * all zeros, then the result is exact. Otherwise round in the + * correct direction. Underflow is possible. If a postnormalization + * is necessary, then the mantissa is all zeros so no shift is needed. + */ + round: + if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { + Dblext_denormalize(resultp1,resultp2,resultp3,resultp4, + result_exponent,is_tiny); + } + Dbl_set_sign(resultp1,/*using*/sign_save); + if (Dblext_isnotzero_mantissap3(resultp3) || + Dblext_isnotzero_mantissap4(resultp4)) { + inexact = TRUE; + switch(Rounding_mode()) { + case ROUNDNEAREST: /* The default. */ + if (Dblext_isone_highp3(resultp3)) { + /* at least 1/2 ulp */ + if (Dblext_isnotzero_low31p3(resultp3) || + Dblext_isnotzero_mantissap4(resultp4) || + Dblext_isone_lowp2(resultp2)) { + /* either exactly half way and odd or + * more than 1/2ulp */ + Dbl_increment(resultp1,resultp2); + } + } + break; + + case ROUNDPLUS: + if (Dbl_iszero_sign(resultp1)) { + /* Round up positive results */ + Dbl_increment(resultp1,resultp2); + } + break; + + case ROUNDMINUS: + if (Dbl_isone_sign(resultp1)) { + /* Round down negative results */ + Dbl_increment(resultp1,resultp2); + } + + case ROUNDZERO:; + /* truncate is simple */ + } /* end switch... */ + if (Dbl_isone_hiddenoverflow(resultp1)) result_exponent++; + } + if (result_exponent >= DBL_INFINITY_EXPONENT) { + /* Overflow */ + if (Is_overflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Dbl_setwrapped_exponent(resultp1,result_exponent,ovfl); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_OVERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return (OPC_2E_OVERFLOWEXCEPTION); + } + inexact = TRUE; + Set_overflowflag(); + Dbl_setoverflow(resultp1,resultp2); + } else if (result_exponent <= 0) { /* underflow case */ + if (Is_underflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Dbl_setwrapped_exponent(resultp1,result_exponent,unfl); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_UNDERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(OPC_2E_UNDERFLOWEXCEPTION); + } + else if (inexact && is_tiny) Set_underflowflag(); + } + else Dbl_set_exponent(resultp1,result_exponent); + Dbl_copytoptr(resultp1,resultp2,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(NOEXCEPTION); +} + +/* + * Single Floating-point Multiply Fused Add + */ + +sgl_fmpyfadd(src1ptr,src2ptr,src3ptr,status,dstptr) + +sgl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr; +unsigned int *status; +{ + unsigned int opnd1, opnd2, opnd3; + register unsigned int tmpresp1, tmpresp2; + unsigned int rightp1, rightp2; + unsigned int resultp1, resultp2 = 0; + register int mpy_exponent, add_exponent, count; + boolean inexact = FALSE, is_tiny = FALSE; + + unsigned int signlessleft1, signlessright1, save; + register int result_exponent, diff_exponent; + int sign_save, jumpsize; + + Sgl_copyfromptr(src1ptr,opnd1); + Sgl_copyfromptr(src2ptr,opnd2); + Sgl_copyfromptr(src3ptr,opnd3); + + /* + * set sign bit of result of multiply + */ + if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) + Sgl_setnegativezero(resultp1); + else Sgl_setzero(resultp1); + + /* + * Generate multiply exponent + */ + mpy_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS; + + /* + * check first operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(opnd1)) { + if (Sgl_iszero_mantissa(opnd1)) { + if (Sgl_isnotnan(opnd2) && Sgl_isnotnan(opnd3)) { + if (Sgl_iszero_exponentmantissa(opnd2)) { + /* + * invalid since operands are infinity + * and zero + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Sgl_isinfinity(opnd3) && + (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Sgl_setinfinity_exponentmantissa(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(opnd1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd1); + } + /* + * is second operand a signaling NaN? + */ + else if (Sgl_is_signalingnan(opnd2)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd2); + Sgl_copytoptr(opnd2,dstptr); + return(NOEXCEPTION); + } + /* + * is third operand a signaling NaN? + */ + else if (Sgl_is_signalingnan(opnd3)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd3); + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Sgl_copytoptr(opnd1,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check second operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(opnd2)) { + if (Sgl_iszero_mantissa(opnd2)) { + if (Sgl_isnotnan(opnd3)) { + if (Sgl_iszero_exponentmantissa(opnd1)) { + /* + * invalid since multiply operands are + * zero & infinity + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(opnd2); + Sgl_copytoptr(opnd2,dstptr); + return(NOEXCEPTION); + } + + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Sgl_isinfinity(opnd3) && + (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Sgl_setinfinity_exponentmantissa(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(opnd2)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd2); + } + /* + * is third operand a signaling NaN? + */ + else if (Sgl_is_signalingnan(opnd3)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd3); + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Sgl_copytoptr(opnd2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check third operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(opnd3)) { + if (Sgl_iszero_mantissa(opnd3)) { + /* return infinity */ + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } else { + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(opnd3)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd3); + } + /* + * return quiet NaN + */ + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + } + + /* + * Generate multiply mantissa + */ + if (Sgl_isnotzero_exponent(opnd1)) { + /* set hidden bit */ + Sgl_clear_signexponent_set_hidden(opnd1); + } + else { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd1)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Sgl_iszero_exponentmantissa(opnd3)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Sgl_or_signs(opnd3,resultp1); + } else { + Sgl_and_signs(opnd3,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Sgl_iszero_exponent(opnd3) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Sgl_signextendedsign(opnd3); + result_exponent = 0; + Sgl_leftshiftby1(opnd3); + Sgl_normalize(opnd3,result_exponent); + Sgl_set_sign(opnd3,/*using*/sign_save); + Sgl_setwrapped_exponent(opnd3,result_exponent, + unfl); + Sgl_copytoptr(opnd3,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* is denormalized, adjust exponent */ + Sgl_clear_signexponent(opnd1); + Sgl_leftshiftby1(opnd1); + Sgl_normalize(opnd1,mpy_exponent); + } + /* opnd2 needs to have hidden bit set with msb in hidden bit */ + if (Sgl_isnotzero_exponent(opnd2)) { + Sgl_clear_signexponent_set_hidden(opnd2); + } + else { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd2)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Sgl_iszero_exponentmantissa(opnd3)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Sgl_or_signs(opnd3,resultp1); + } else { + Sgl_and_signs(opnd3,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Sgl_iszero_exponent(opnd3) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Sgl_signextendedsign(opnd3); + result_exponent = 0; + Sgl_leftshiftby1(opnd3); + Sgl_normalize(opnd3,result_exponent); + Sgl_set_sign(opnd3,/*using*/sign_save); + Sgl_setwrapped_exponent(opnd3,result_exponent, + unfl); + Sgl_copytoptr(opnd3,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* is denormalized; want to normalize */ + Sgl_clear_signexponent(opnd2); + Sgl_leftshiftby1(opnd2); + Sgl_normalize(opnd2,mpy_exponent); + } + + /* Multiply the first two source mantissas together */ + + /* + * The intermediate result will be kept in tmpres, + * which needs enough room for 106 bits of mantissa, + * so lets call it a Double extended. + */ + Sglext_setzero(tmpresp1,tmpresp2); + + /* + * Four bits at a time are inspected in each loop, and a + * simple shift and add multiply algorithm is used. + */ + for (count = SGL_P-1; count >= 0; count -= 4) { + Sglext_rightshiftby4(tmpresp1,tmpresp2); + if (Sbit28(opnd1)) { + /* Twoword_add should be an ADD followed by 2 ADDC's */ + Twoword_add(tmpresp1, tmpresp2, opnd2<<3, 0); + } + if (Sbit29(opnd1)) { + Twoword_add(tmpresp1, tmpresp2, opnd2<<2, 0); + } + if (Sbit30(opnd1)) { + Twoword_add(tmpresp1, tmpresp2, opnd2<<1, 0); + } + if (Sbit31(opnd1)) { + Twoword_add(tmpresp1, tmpresp2, opnd2, 0); + } + Sgl_rightshiftby4(opnd1); + } + if (Is_sexthiddenoverflow(tmpresp1)) { + /* result mantissa >= 2 (mantissa overflow) */ + mpy_exponent++; + Sglext_rightshiftby4(tmpresp1,tmpresp2); + } else { + Sglext_rightshiftby3(tmpresp1,tmpresp2); + } + + /* + * Restore the sign of the mpy result which was saved in resultp1. + * The exponent will continue to be kept in mpy_exponent. + */ + Sglext_set_sign(tmpresp1,Sgl_sign(resultp1)); + + /* + * No rounding is required, since the result of the multiply + * is exact in the extended format. + */ + + /* + * Now we are ready to perform the add portion of the operation. + * + * The exponents need to be kept as integers for now, since the + * multiply result might not fit into the exponent field. We + * can't overflow or underflow because of this yet, since the + * add could bring the final result back into range. + */ + add_exponent = Sgl_exponent(opnd3); + + /* + * Check for denormalized or zero add operand. + */ + if (add_exponent == 0) { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd3)) { + /* right is zero */ + /* Left can't be zero and must be result. + * + * The final result is now in tmpres and mpy_exponent, + * and needs to be rounded and squeezed back into + * double precision format from double extended. + */ + result_exponent = mpy_exponent; + Sglext_copy(tmpresp1,tmpresp2,resultp1,resultp2); + sign_save = Sgl_signextendedsign(resultp1);/*save sign*/ + goto round; + } + + /* + * Neither are zeroes. + * Adjust exponent and normalize add operand. + */ + sign_save = Sgl_signextendedsign(opnd3); /* save sign */ + Sgl_clear_signexponent(opnd3); + Sgl_leftshiftby1(opnd3); + Sgl_normalize(opnd3,add_exponent); + Sgl_set_sign(opnd3,sign_save); /* restore sign */ + } else { + Sgl_clear_exponent_set_hidden(opnd3); + } + /* + * Copy opnd3 to the double extended variable called right. + */ + Sgl_copyto_sglext(opnd3,rightp1,rightp2); + + /* + * A zero "save" helps discover equal operands (for later), + * and is used in swapping operands (if needed). + */ + Sglext_xortointp1(tmpresp1,rightp1,/*to*/save); + + /* + * Compare magnitude of operands. + */ + Sglext_copytoint_exponentmantissa(tmpresp1,signlessleft1); + Sglext_copytoint_exponentmantissa(rightp1,signlessright1); + if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && + Sglext_ismagnitudeless(signlessleft1,signlessright1)) { + /* + * Set the left operand to the larger one by XOR swap. + * First finish the first word "save". + */ + Sglext_xorfromintp1(save,rightp1,/*to*/rightp1); + Sglext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); + Sglext_swap_lower(tmpresp2,rightp2); + /* also setup exponents used in rest of routine */ + diff_exponent = add_exponent - mpy_exponent; + result_exponent = add_exponent; + } else { + /* also setup exponents used in rest of routine */ + diff_exponent = mpy_exponent - add_exponent; + result_exponent = mpy_exponent; + } + /* Invariant: left is not smaller than right. */ + + /* + * Special case alignment of operands that would force alignment + * beyond the extent of the extension. A further optimization + * could special case this but only reduces the path length for + * this infrequent case. + */ + if (diff_exponent > SGLEXT_THRESHOLD) { + diff_exponent = SGLEXT_THRESHOLD; + } + + /* Align right operand by shifting it to the right */ + Sglext_clear_sign(rightp1); + Sglext_right_align(rightp1,rightp2,/*shifted by*/diff_exponent); + + /* Treat sum and difference of the operands separately. */ + if ((int)save < 0) { + /* + * Difference of the two operands. Overflow can occur if the + * multiply overflowed. A borrow can occur out of the hidden + * bit and force a post normalization phase. + */ + Sglext_subtract(tmpresp1,tmpresp2, rightp1,rightp2, + resultp1,resultp2); + sign_save = Sgl_signextendedsign(resultp1); + if (Sgl_iszero_hidden(resultp1)) { + /* Handle normalization */ + /* A straight foward algorithm would now shift the + * result and extension left until the hidden bit + * becomes one. Not all of the extension bits need + * participate in the shift. Only the two most + * significant bits (round and guard) are needed. + * If only a single shift is needed then the guard + * bit becomes a significant low order bit and the + * extension must participate in the rounding. + * If more than a single shift is needed, then all + * bits to the right of the guard bit are zeros, + * and the guard bit may or may not be zero. */ + Sglext_leftshiftby1(resultp1,resultp2); + + /* Need to check for a zero result. The sign and + * exponent fields have already been zeroed. The more + * efficient test of the full object can be used. + */ + if (Sglext_iszero(resultp1,resultp2)) { + /* Must have been "x-x" or "x+(-x)". */ + if (Is_rounding_mode(ROUNDMINUS)) + Sgl_setone_sign(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + result_exponent--; + + /* Look to see if normalization is finished. */ + if (Sgl_isone_hidden(resultp1)) { + /* No further normalization is needed */ + goto round; + } + + /* Discover first one bit to determine shift amount. + * Use a modified binary search. We have already + * shifted the result one position right and still + * not found a one so the remainder of the extension + * must be zero and simplifies rounding. */ + /* Scan bytes */ + while (Sgl_iszero_hiddenhigh7mantissa(resultp1)) { + Sglext_leftshiftby8(resultp1,resultp2); + result_exponent -= 8; + } + /* Now narrow it down to the nibble */ + if (Sgl_iszero_hiddenhigh3mantissa(resultp1)) { + /* The lower nibble contains the + * normalizing one */ + Sglext_leftshiftby4(resultp1,resultp2); + result_exponent -= 4; + } + /* Select case where first bit is set (already + * normalized) otherwise select the proper shift. */ + jumpsize = Sgl_hiddenhigh3mantissa(resultp1); + if (jumpsize <= 7) switch(jumpsize) { + case 1: + Sglext_leftshiftby3(resultp1,resultp2); + result_exponent -= 3; + break; + case 2: + case 3: + Sglext_leftshiftby2(resultp1,resultp2); + result_exponent -= 2; + break; + case 4: + case 5: + case 6: + case 7: + Sglext_leftshiftby1(resultp1,resultp2); + result_exponent -= 1; + break; + } + } /* end if (hidden...)... */ + /* Fall through and round */ + } /* end if (save < 0)... */ + else { + /* Add magnitudes */ + Sglext_addition(tmpresp1,tmpresp2, + rightp1,rightp2, /*to*/resultp1,resultp2); + sign_save = Sgl_signextendedsign(resultp1); + if (Sgl_isone_hiddenoverflow(resultp1)) { + /* Prenormalization required. */ + Sglext_arithrightshiftby1(resultp1,resultp2); + result_exponent++; + } /* end if hiddenoverflow... */ + } /* end else ...add magnitudes... */ + + /* Round the result. If the extension and lower two words are + * all zeros, then the result is exact. Otherwise round in the + * correct direction. Underflow is possible. If a postnormalization + * is necessary, then the mantissa is all zeros so no shift is needed. + */ + round: + if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { + Sglext_denormalize(resultp1,resultp2,result_exponent,is_tiny); + } + Sgl_set_sign(resultp1,/*using*/sign_save); + if (Sglext_isnotzero_mantissap2(resultp2)) { + inexact = TRUE; + switch(Rounding_mode()) { + case ROUNDNEAREST: /* The default. */ + if (Sglext_isone_highp2(resultp2)) { + /* at least 1/2 ulp */ + if (Sglext_isnotzero_low31p2(resultp2) || + Sglext_isone_lowp1(resultp1)) { + /* either exactly half way and odd or + * more than 1/2ulp */ + Sgl_increment(resultp1); + } + } + break; + + case ROUNDPLUS: + if (Sgl_iszero_sign(resultp1)) { + /* Round up positive results */ + Sgl_increment(resultp1); + } + break; + + case ROUNDMINUS: + if (Sgl_isone_sign(resultp1)) { + /* Round down negative results */ + Sgl_increment(resultp1); + } + + case ROUNDZERO:; + /* truncate is simple */ + } /* end switch... */ + if (Sgl_isone_hiddenoverflow(resultp1)) result_exponent++; + } + if (result_exponent >= SGL_INFINITY_EXPONENT) { + /* Overflow */ + if (Is_overflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Sgl_setwrapped_exponent(resultp1,result_exponent,ovfl); + Sgl_copytoptr(resultp1,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_OVERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return (OPC_2E_OVERFLOWEXCEPTION); + } + inexact = TRUE; + Set_overflowflag(); + Sgl_setoverflow(resultp1); + } else if (result_exponent <= 0) { /* underflow case */ + if (Is_underflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Sgl_setwrapped_exponent(resultp1,result_exponent,unfl); + Sgl_copytoptr(resultp1,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_UNDERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(OPC_2E_UNDERFLOWEXCEPTION); + } + else if (inexact && is_tiny) Set_underflowflag(); + } + else Sgl_set_exponent(resultp1,result_exponent); + Sgl_copytoptr(resultp1,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(NOEXCEPTION); +} + +/* + * Single Floating-point Multiply Negate Fused Add + */ + +sgl_fmpynfadd(src1ptr,src2ptr,src3ptr,status,dstptr) + +sgl_floating_point *src1ptr, *src2ptr, *src3ptr, *dstptr; +unsigned int *status; +{ + unsigned int opnd1, opnd2, opnd3; + register unsigned int tmpresp1, tmpresp2; + unsigned int rightp1, rightp2; + unsigned int resultp1, resultp2 = 0; + register int mpy_exponent, add_exponent, count; + boolean inexact = FALSE, is_tiny = FALSE; + + unsigned int signlessleft1, signlessright1, save; + register int result_exponent, diff_exponent; + int sign_save, jumpsize; + + Sgl_copyfromptr(src1ptr,opnd1); + Sgl_copyfromptr(src2ptr,opnd2); + Sgl_copyfromptr(src3ptr,opnd3); + + /* + * set sign bit of result of multiply + */ + if (Sgl_sign(opnd1) ^ Sgl_sign(opnd2)) + Sgl_setzero(resultp1); + else + Sgl_setnegativezero(resultp1); + + /* + * Generate multiply exponent + */ + mpy_exponent = Sgl_exponent(opnd1) + Sgl_exponent(opnd2) - SGL_BIAS; + + /* + * check first operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(opnd1)) { + if (Sgl_iszero_mantissa(opnd1)) { + if (Sgl_isnotnan(opnd2) && Sgl_isnotnan(opnd3)) { + if (Sgl_iszero_exponentmantissa(opnd2)) { + /* + * invalid since operands are infinity + * and zero + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Sgl_isinfinity(opnd3) && + (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Sgl_setinfinity_exponentmantissa(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(opnd1)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd1); + } + /* + * is second operand a signaling NaN? + */ + else if (Sgl_is_signalingnan(opnd2)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd2); + Sgl_copytoptr(opnd2,dstptr); + return(NOEXCEPTION); + } + /* + * is third operand a signaling NaN? + */ + else if (Sgl_is_signalingnan(opnd3)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd3); + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Sgl_copytoptr(opnd1,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check second operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(opnd2)) { + if (Sgl_iszero_mantissa(opnd2)) { + if (Sgl_isnotnan(opnd3)) { + if (Sgl_iszero_exponentmantissa(opnd1)) { + /* + * invalid since multiply operands are + * zero & infinity + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(opnd2); + Sgl_copytoptr(opnd2,dstptr); + return(NOEXCEPTION); + } + + /* + * Check third operand for infinity with a + * sign opposite of the multiply result + */ + if (Sgl_isinfinity(opnd3) && + (Sgl_sign(resultp1) ^ Sgl_sign(opnd3))) { + /* + * invalid since attempting a magnitude + * subtraction of infinities + */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + Set_invalidflag(); + Sgl_makequietnan(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + + /* + * return infinity + */ + Sgl_setinfinity_exponentmantissa(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + } + else { + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(opnd2)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd2); + } + /* + * is third operand a signaling NaN? + */ + else if (Sgl_is_signalingnan(opnd3)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd3); + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* + * return quiet NaN + */ + Sgl_copytoptr(opnd2,dstptr); + return(NOEXCEPTION); + } + } + + /* + * check third operand for NaN's or infinity + */ + if (Sgl_isinfinity_exponent(opnd3)) { + if (Sgl_iszero_mantissa(opnd3)) { + /* return infinity */ + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } else { + /* + * is NaN; signaling or quiet? + */ + if (Sgl_isone_signaling(opnd3)) { + /* trap if INVALIDTRAP enabled */ + if (Is_invalidtrap_enabled()) + return(OPC_2E_INVALIDEXCEPTION); + /* make NaN quiet */ + Set_invalidflag(); + Sgl_set_quiet(opnd3); + } + /* + * return quiet NaN + */ + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + } + + /* + * Generate multiply mantissa + */ + if (Sgl_isnotzero_exponent(opnd1)) { + /* set hidden bit */ + Sgl_clear_signexponent_set_hidden(opnd1); + } + else { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd1)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Sgl_iszero_exponentmantissa(opnd3)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Sgl_or_signs(opnd3,resultp1); + } else { + Sgl_and_signs(opnd3,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Sgl_iszero_exponent(opnd3) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Sgl_signextendedsign(opnd3); + result_exponent = 0; + Sgl_leftshiftby1(opnd3); + Sgl_normalize(opnd3,result_exponent); + Sgl_set_sign(opnd3,/*using*/sign_save); + Sgl_setwrapped_exponent(opnd3,result_exponent, + unfl); + Sgl_copytoptr(opnd3,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* is denormalized, adjust exponent */ + Sgl_clear_signexponent(opnd1); + Sgl_leftshiftby1(opnd1); + Sgl_normalize(opnd1,mpy_exponent); + } + /* opnd2 needs to have hidden bit set with msb in hidden bit */ + if (Sgl_isnotzero_exponent(opnd2)) { + Sgl_clear_signexponent_set_hidden(opnd2); + } + else { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd2)) { + /* + * Perform the add opnd3 with zero here. + */ + if (Sgl_iszero_exponentmantissa(opnd3)) { + if (Is_rounding_mode(ROUNDMINUS)) { + Sgl_or_signs(opnd3,resultp1); + } else { + Sgl_and_signs(opnd3,resultp1); + } + } + /* + * Now let's check for trapped underflow case. + */ + else if (Sgl_iszero_exponent(opnd3) && + Is_underflowtrap_enabled()) { + /* need to normalize results mantissa */ + sign_save = Sgl_signextendedsign(opnd3); + result_exponent = 0; + Sgl_leftshiftby1(opnd3); + Sgl_normalize(opnd3,result_exponent); + Sgl_set_sign(opnd3,/*using*/sign_save); + Sgl_setwrapped_exponent(opnd3,result_exponent, + unfl); + Sgl_copytoptr(opnd3,dstptr); + /* inexact = FALSE */ + return(OPC_2E_UNDERFLOWEXCEPTION); + } + Sgl_copytoptr(opnd3,dstptr); + return(NOEXCEPTION); + } + /* is denormalized; want to normalize */ + Sgl_clear_signexponent(opnd2); + Sgl_leftshiftby1(opnd2); + Sgl_normalize(opnd2,mpy_exponent); + } + + /* Multiply the first two source mantissas together */ + + /* + * The intermediate result will be kept in tmpres, + * which needs enough room for 106 bits of mantissa, + * so lets call it a Double extended. + */ + Sglext_setzero(tmpresp1,tmpresp2); + + /* + * Four bits at a time are inspected in each loop, and a + * simple shift and add multiply algorithm is used. + */ + for (count = SGL_P-1; count >= 0; count -= 4) { + Sglext_rightshiftby4(tmpresp1,tmpresp2); + if (Sbit28(opnd1)) { + /* Twoword_add should be an ADD followed by 2 ADDC's */ + Twoword_add(tmpresp1, tmpresp2, opnd2<<3, 0); + } + if (Sbit29(opnd1)) { + Twoword_add(tmpresp1, tmpresp2, opnd2<<2, 0); + } + if (Sbit30(opnd1)) { + Twoword_add(tmpresp1, tmpresp2, opnd2<<1, 0); + } + if (Sbit31(opnd1)) { + Twoword_add(tmpresp1, tmpresp2, opnd2, 0); + } + Sgl_rightshiftby4(opnd1); + } + if (Is_sexthiddenoverflow(tmpresp1)) { + /* result mantissa >= 2 (mantissa overflow) */ + mpy_exponent++; + Sglext_rightshiftby4(tmpresp1,tmpresp2); + } else { + Sglext_rightshiftby3(tmpresp1,tmpresp2); + } + + /* + * Restore the sign of the mpy result which was saved in resultp1. + * The exponent will continue to be kept in mpy_exponent. + */ + Sglext_set_sign(tmpresp1,Sgl_sign(resultp1)); + + /* + * No rounding is required, since the result of the multiply + * is exact in the extended format. + */ + + /* + * Now we are ready to perform the add portion of the operation. + * + * The exponents need to be kept as integers for now, since the + * multiply result might not fit into the exponent field. We + * can't overflow or underflow because of this yet, since the + * add could bring the final result back into range. + */ + add_exponent = Sgl_exponent(opnd3); + + /* + * Check for denormalized or zero add operand. + */ + if (add_exponent == 0) { + /* check for zero */ + if (Sgl_iszero_mantissa(opnd3)) { + /* right is zero */ + /* Left can't be zero and must be result. + * + * The final result is now in tmpres and mpy_exponent, + * and needs to be rounded and squeezed back into + * double precision format from double extended. + */ + result_exponent = mpy_exponent; + Sglext_copy(tmpresp1,tmpresp2,resultp1,resultp2); + sign_save = Sgl_signextendedsign(resultp1);/*save sign*/ + goto round; + } + + /* + * Neither are zeroes. + * Adjust exponent and normalize add operand. + */ + sign_save = Sgl_signextendedsign(opnd3); /* save sign */ + Sgl_clear_signexponent(opnd3); + Sgl_leftshiftby1(opnd3); + Sgl_normalize(opnd3,add_exponent); + Sgl_set_sign(opnd3,sign_save); /* restore sign */ + } else { + Sgl_clear_exponent_set_hidden(opnd3); + } + /* + * Copy opnd3 to the double extended variable called right. + */ + Sgl_copyto_sglext(opnd3,rightp1,rightp2); + + /* + * A zero "save" helps discover equal operands (for later), + * and is used in swapping operands (if needed). + */ + Sglext_xortointp1(tmpresp1,rightp1,/*to*/save); + + /* + * Compare magnitude of operands. + */ + Sglext_copytoint_exponentmantissa(tmpresp1,signlessleft1); + Sglext_copytoint_exponentmantissa(rightp1,signlessright1); + if (mpy_exponent < add_exponent || mpy_exponent == add_exponent && + Sglext_ismagnitudeless(signlessleft1,signlessright1)) { + /* + * Set the left operand to the larger one by XOR swap. + * First finish the first word "save". + */ + Sglext_xorfromintp1(save,rightp1,/*to*/rightp1); + Sglext_xorfromintp1(save,tmpresp1,/*to*/tmpresp1); + Sglext_swap_lower(tmpresp2,rightp2); + /* also setup exponents used in rest of routine */ + diff_exponent = add_exponent - mpy_exponent; + result_exponent = add_exponent; + } else { + /* also setup exponents used in rest of routine */ + diff_exponent = mpy_exponent - add_exponent; + result_exponent = mpy_exponent; + } + /* Invariant: left is not smaller than right. */ + + /* + * Special case alignment of operands that would force alignment + * beyond the extent of the extension. A further optimization + * could special case this but only reduces the path length for + * this infrequent case. + */ + if (diff_exponent > SGLEXT_THRESHOLD) { + diff_exponent = SGLEXT_THRESHOLD; + } + + /* Align right operand by shifting it to the right */ + Sglext_clear_sign(rightp1); + Sglext_right_align(rightp1,rightp2,/*shifted by*/diff_exponent); + + /* Treat sum and difference of the operands separately. */ + if ((int)save < 0) { + /* + * Difference of the two operands. Overflow can occur if the + * multiply overflowed. A borrow can occur out of the hidden + * bit and force a post normalization phase. + */ + Sglext_subtract(tmpresp1,tmpresp2, rightp1,rightp2, + resultp1,resultp2); + sign_save = Sgl_signextendedsign(resultp1); + if (Sgl_iszero_hidden(resultp1)) { + /* Handle normalization */ + /* A straight foward algorithm would now shift the + * result and extension left until the hidden bit + * becomes one. Not all of the extension bits need + * participate in the shift. Only the two most + * significant bits (round and guard) are needed. + * If only a single shift is needed then the guard + * bit becomes a significant low order bit and the + * extension must participate in the rounding. + * If more than a single shift is needed, then all + * bits to the right of the guard bit are zeros, + * and the guard bit may or may not be zero. */ + Sglext_leftshiftby1(resultp1,resultp2); + + /* Need to check for a zero result. The sign and + * exponent fields have already been zeroed. The more + * efficient test of the full object can be used. + */ + if (Sglext_iszero(resultp1,resultp2)) { + /* Must have been "x-x" or "x+(-x)". */ + if (Is_rounding_mode(ROUNDMINUS)) + Sgl_setone_sign(resultp1); + Sgl_copytoptr(resultp1,dstptr); + return(NOEXCEPTION); + } + result_exponent--; + + /* Look to see if normalization is finished. */ + if (Sgl_isone_hidden(resultp1)) { + /* No further normalization is needed */ + goto round; + } + + /* Discover first one bit to determine shift amount. + * Use a modified binary search. We have already + * shifted the result one position right and still + * not found a one so the remainder of the extension + * must be zero and simplifies rounding. */ + /* Scan bytes */ + while (Sgl_iszero_hiddenhigh7mantissa(resultp1)) { + Sglext_leftshiftby8(resultp1,resultp2); + result_exponent -= 8; + } + /* Now narrow it down to the nibble */ + if (Sgl_iszero_hiddenhigh3mantissa(resultp1)) { + /* The lower nibble contains the + * normalizing one */ + Sglext_leftshiftby4(resultp1,resultp2); + result_exponent -= 4; + } + /* Select case where first bit is set (already + * normalized) otherwise select the proper shift. */ + jumpsize = Sgl_hiddenhigh3mantissa(resultp1); + if (jumpsize <= 7) switch(jumpsize) { + case 1: + Sglext_leftshiftby3(resultp1,resultp2); + result_exponent -= 3; + break; + case 2: + case 3: + Sglext_leftshiftby2(resultp1,resultp2); + result_exponent -= 2; + break; + case 4: + case 5: + case 6: + case 7: + Sglext_leftshiftby1(resultp1,resultp2); + result_exponent -= 1; + break; + } + } /* end if (hidden...)... */ + /* Fall through and round */ + } /* end if (save < 0)... */ + else { + /* Add magnitudes */ + Sglext_addition(tmpresp1,tmpresp2, + rightp1,rightp2, /*to*/resultp1,resultp2); + sign_save = Sgl_signextendedsign(resultp1); + if (Sgl_isone_hiddenoverflow(resultp1)) { + /* Prenormalization required. */ + Sglext_arithrightshiftby1(resultp1,resultp2); + result_exponent++; + } /* end if hiddenoverflow... */ + } /* end else ...add magnitudes... */ + + /* Round the result. If the extension and lower two words are + * all zeros, then the result is exact. Otherwise round in the + * correct direction. Underflow is possible. If a postnormalization + * is necessary, then the mantissa is all zeros so no shift is needed. + */ + round: + if (result_exponent <= 0 && !Is_underflowtrap_enabled()) { + Sglext_denormalize(resultp1,resultp2,result_exponent,is_tiny); + } + Sgl_set_sign(resultp1,/*using*/sign_save); + if (Sglext_isnotzero_mantissap2(resultp2)) { + inexact = TRUE; + switch(Rounding_mode()) { + case ROUNDNEAREST: /* The default. */ + if (Sglext_isone_highp2(resultp2)) { + /* at least 1/2 ulp */ + if (Sglext_isnotzero_low31p2(resultp2) || + Sglext_isone_lowp1(resultp1)) { + /* either exactly half way and odd or + * more than 1/2ulp */ + Sgl_increment(resultp1); + } + } + break; + + case ROUNDPLUS: + if (Sgl_iszero_sign(resultp1)) { + /* Round up positive results */ + Sgl_increment(resultp1); + } + break; + + case ROUNDMINUS: + if (Sgl_isone_sign(resultp1)) { + /* Round down negative results */ + Sgl_increment(resultp1); + } + + case ROUNDZERO:; + /* truncate is simple */ + } /* end switch... */ + if (Sgl_isone_hiddenoverflow(resultp1)) result_exponent++; + } + if (result_exponent >= SGL_INFINITY_EXPONENT) { + /* Overflow */ + if (Is_overflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Sgl_setwrapped_exponent(resultp1,result_exponent,ovfl); + Sgl_copytoptr(resultp1,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_OVERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return (OPC_2E_OVERFLOWEXCEPTION); + } + inexact = TRUE; + Set_overflowflag(); + Sgl_setoverflow(resultp1); + } else if (result_exponent <= 0) { /* underflow case */ + if (Is_underflowtrap_enabled()) { + /* + * Adjust bias of result + */ + Sgl_setwrapped_exponent(resultp1,result_exponent,unfl); + Sgl_copytoptr(resultp1,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) + return (OPC_2E_UNDERFLOWEXCEPTION | + OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(OPC_2E_UNDERFLOWEXCEPTION); + } + else if (inexact && is_tiny) Set_underflowflag(); + } + else Sgl_set_exponent(resultp1,result_exponent); + Sgl_copytoptr(resultp1,dstptr); + if (inexact) + if (Is_inexacttrap_enabled()) return(OPC_2E_INEXACTEXCEPTION); + else Set_inexactflag(); + return(NOEXCEPTION); +} + |