From 198f70589e3c0f0f50da646152443787e959228f Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 13 Nov 2015 00:47:08 +0000 Subject: MIPS: math-emu: Add IEEE Std 754-2008 ABS.fmt and NEG.fmt emulation Implement IEEE Std 754-2008 non-arithmetic ABS.fmt and NEG.fmt emulation wired to the state of the FCSR.ABS2008 bit. In the non-arithmetic mode the sign bit is altered according to the operation requested regardless of the datum encoded in the input operand, no other bits are changed, the resulting bit pattern is written to the output operand and no exception is ever signalled. Signed-off-by: Maciej W. Rozycki Cc: Andrew Morton Cc: Matthew Fortune Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/11476/ Signed-off-by: Ralf Baechle --- arch/mips/math-emu/sp_simple.c | 38 +++++++++++++++++++++++++------------- 1 file changed, 25 insertions(+), 13 deletions(-) (limited to 'arch/mips/math-emu/sp_simple.c') diff --git a/arch/mips/math-emu/sp_simple.c b/arch/mips/math-emu/sp_simple.c index c50e9451f2d2..756c9cf2dfd2 100644 --- a/arch/mips/math-emu/sp_simple.c +++ b/arch/mips/math-emu/sp_simple.c @@ -23,27 +23,39 @@ union ieee754sp ieee754sp_neg(union ieee754sp x) { - unsigned int oldrm; union ieee754sp y; - oldrm = ieee754_csr.rm; - ieee754_csr.rm = FPU_CSR_RD; - y = ieee754sp_sub(ieee754sp_zero(0), x); - ieee754_csr.rm = oldrm; + if (ieee754_csr.abs2008) { + y = x; + SPSIGN(y) = !SPSIGN(x); + } else { + unsigned int oldrm; + + oldrm = ieee754_csr.rm; + ieee754_csr.rm = FPU_CSR_RD; + y = ieee754sp_sub(ieee754sp_zero(0), x); + ieee754_csr.rm = oldrm; + } return y; } union ieee754sp ieee754sp_abs(union ieee754sp x) { - unsigned int oldrm; union ieee754sp y; - oldrm = ieee754_csr.rm; - ieee754_csr.rm = FPU_CSR_RD; - if (SPSIGN(x)) - y = ieee754sp_sub(ieee754sp_zero(0), x); - else - y = ieee754sp_add(ieee754sp_zero(0), x); - ieee754_csr.rm = oldrm; + if (ieee754_csr.abs2008) { + y = x; + SPSIGN(y) = 0; + } else { + unsigned int oldrm; + + oldrm = ieee754_csr.rm; + ieee754_csr.rm = FPU_CSR_RD; + if (SPSIGN(x)) + y = ieee754sp_sub(ieee754sp_zero(0), x); + else + y = ieee754sp_add(ieee754sp_zero(0), x); + ieee754_csr.rm = oldrm; + } return y; } -- cgit v1.2.3