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powerpc/lib/sstep: Add cmpb instruction emulation

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This patch adds emulation of the cmpb instruction, enabling xmon to
emulate this instruction.
Tested for correctness against the cmpb asm instruction on ppc64le.

Signed-off-by: Matt Brown <matthew.brown.dev@gmail.com>
Reviewed-by: Cyril Bur <cyrilbur@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Matt Brown 2017-07-31 10:58:22 +10:00 committed by Michael Ellerman
parent 93fc5ca9a0
commit 02c0f62a60
1 changed files with 20 additions and 0 deletions
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20
arch/powerpc/lib/sstep.c
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@ -596,6 +596,22 @@ static nokprobe_inline void do_cmp_unsigned(struct pt_regs *regs, unsigned long
regs->ccr = (regs->ccr & ~(0xf << shift)) | (crval << shift);
}
static nokprobe_inline void do_cmpb(struct pt_regs *regs, unsigned long v1,
unsigned long v2, int rd)
{
unsigned long long out_val, mask;
int i;
out_val = 0;
for (i = 0; i < 8; i++) {
mask = 0xffUL << (i * 8);
if ((v1 & mask) == (v2 & mask))
out_val |= mask;
}
regs->gpr[rd] = out_val;
}
static nokprobe_inline int trap_compare(long v1, long v2)
{
int ret = 0;
@ -1064,6 +1080,10 @@ int analyse_instr(struct instruction_op *op, struct pt_regs *regs,
do_cmp_unsigned(regs, val, val2, rd >> 2);
goto instr_done;
case 508: /* cmpb */
do_cmpb(regs, regs->gpr[rd], regs->gpr[rb], ra);
goto instr_done;
/*
* Arithmetic instructions
*/