diff options
author | Paul Mundt <lethal@linux-sh.org> | 2007-05-08 14:50:59 +0900 |
---|---|---|
committer | Paul Mundt <lethal@hera.kernel.org> | 2007-05-09 01:35:01 +0000 |
commit | bd0799977cb9b68aa6a39e9630aeea4778a58385 (patch) | |
tree | 125c0c923701c5b6f823a7b614c295e06370d46c /arch/sh/kernel/cpu/sh2a/opcode_helper.c | |
parent | 51c8b856f5edfa45d956721aa6d6ebaa15699062 (diff) | |
download | linux-stable-bd0799977cb9b68aa6a39e9630aeea4778a58385.tar.gz linux-stable-bd0799977cb9b68aa6a39e9630aeea4778a58385.tar.bz2 linux-stable-bd0799977cb9b68aa6a39e9630aeea4778a58385.zip |
sh: Support for SH-2A 32-bit opcodes.
SH-2A supports both 16 and 32-bit instructions, add a simple helper
for figuring out the instruction size in the places where there are
hardcoded 16-bit assumptions.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel/cpu/sh2a/opcode_helper.c')
-rw-r--r-- | arch/sh/kernel/cpu/sh2a/opcode_helper.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/sh2a/opcode_helper.c b/arch/sh/kernel/cpu/sh2a/opcode_helper.c new file mode 100644 index 000000000000..9704b7926d8b --- /dev/null +++ b/arch/sh/kernel/cpu/sh2a/opcode_helper.c @@ -0,0 +1,55 @@ +/* + * arch/sh/kernel/cpu/sh2a/opcode_helper.c + * + * Helper for the SH-2A 32-bit opcodes. + * + * Copyright (C) 2007 Paul Mundt + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#include <linux/kernel.h> +#include <asm/system.h> + +/* + * Instructions on SH are generally fixed at 16-bits, however, SH-2A + * introduces some 32-bit instructions. Since there are no real + * constraints on their use (and they can be mixed and matched), we need + * to check the instruction encoding to work out if it's a true 32-bit + * instruction or not. + * + * Presently, 32-bit opcodes have only slight variations in what the + * actual encoding looks like in the first-half of the instruction, which + * makes it fairly straightforward to differentiate from the 16-bit ones. + * + * First 16-bits of encoding Used by + * + * 0011nnnnmmmm0001 mov.b, mov.w, mov.l, fmov.d, + * fmov.s, movu.b, movu.w + * + * 0011nnnn0iii1001 bclr.b, bld.b, bset.b, bst.b, band.b, + * bandnot.b, bldnot.b, bor.b, bornot.b, + * bxor.b + * + * 0000nnnniiii0000 movi20 + * 0000nnnniiii0001 movi20s + */ +unsigned int instruction_size(unsigned int insn) +{ + /* Look for the common cases */ + switch ((insn & 0xf00f)) { + case 0x0000: /* movi20 */ + case 0x0001: /* movi20s */ + case 0x3001: /* 32-bit mov/fmov/movu variants */ + return 4; + } + + /* And the special cases.. */ + switch ((insn & 0xf08f)) { + case 0x3009: /* 32-bit b*.b bit operations */ + return 4; + } + + return 2; +} |