diff options
| author | Will Schmidt <will_schmidt@vnet.ibm.com> | 2006-08-30 13:11:38 -0500 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2006-09-13 18:39:52 +1000 |
| commit | c3412dcb75ff4d64b44bedc72761d5707d19edf7 (patch) | |
| tree | 3e893de720ce5aca6a3e6471cd6ef0fcbcb62281 | |
| parent | f50d4cfc98d70f919afb2924b1b53c36b2f4e62f (diff) | |
| download | linux-c3412dcb75ff4d64b44bedc72761d5707d19edf7.tar.gz | |
[POWERPC] Emulate power5 popcntb instruction
In an attempt to make it easier for a power5 optimized app to run on a
power4 or a 970 or random earlier machine, this provides emulation of
the popcntb instruction.
Signed-off-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
| -rw-r--r-- | arch/powerpc/kernel/traps.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index 9b352bd0a46011..d9f10f2fc372b2 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -598,6 +598,9 @@ static void parse_fpe(struct pt_regs *regs) #define INST_STSWI 0x7c0005aa #define INST_STSWX 0x7c00052a +#define INST_POPCNTB 0x7c0000f4 +#define INST_POPCNTB_MASK 0xfc0007fe + static int emulate_string_inst(struct pt_regs *regs, u32 instword) { u8 rT = (instword >> 21) & 0x1f; @@ -666,6 +669,23 @@ static int emulate_string_inst(struct pt_regs *regs, u32 instword) return 0; } +static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword) +{ + u32 ra,rs; + unsigned long tmp; + + ra = (instword >> 16) & 0x1f; + rs = (instword >> 21) & 0x1f; + + tmp = regs->gpr[rs]; + tmp = tmp - ((tmp >> 1) & 0x5555555555555555ULL); + tmp = (tmp & 0x3333333333333333ULL) + ((tmp >> 2) & 0x3333333333333333ULL); + tmp = (tmp + (tmp >> 4)) & 0x0f0f0f0f0f0f0f0fULL; + regs->gpr[ra] = tmp; + + return 0; +} + static int emulate_instruction(struct pt_regs *regs) { u32 instword; @@ -703,6 +723,11 @@ static int emulate_instruction(struct pt_regs *regs) if ((instword & INST_STRING_GEN_MASK) == INST_STRING) return emulate_string_inst(regs, instword); + /* Emulate the popcntb (Population Count Bytes) instruction. */ + if ((instword & INST_POPCNTB_MASK) == INST_POPCNTB) { + return emulate_popcntb_inst(regs, instword); + } + return -EINVAL; } |