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....@gmail.com>
---
v2:
- fixed opcode
- fixed mask typecasting
---
arch/powerpc/lib/sstep.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 33117f8..87d277f 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -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;
@@ -1049,6 +1065,10 @@ 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
*/
--
2.9.3
