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target/i386: tcg: high bits SSE cmp operation must be ignored

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High bits in the immediate operand of SSE comparisons are ignored, they
do not result in an undefined opcode exception.  This is mentioned
explicitly in the Intel documentation.

Reported-by: sonicadvance1@gmail.com
Closes: https://gitlab.com/qemu-project/qemu/-/issues/184
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2022-03-24 09:08:39 +01:00
parent 98a02bc449
commit de65b39a51
1 changed files with 2 additions and 4 deletions
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6
target/i386/tcg/translate.c
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@ -4509,10 +4509,8 @@ static void gen_sse(CPUX86State *env, DisasContext *s, int b,
sse_fn_ppi(s->ptr0, s->ptr1, tcg_const_i32(val));
break;
case 0xc2:
/* compare insns */
val = x86_ldub_code(env, s);
if (val >= 8)
goto unknown_op;
/* compare insns, bits 7:3 (7:5 for AVX) are ignored */
val = x86_ldub_code(env, s) & 7;
sse_fn_epp = sse_op_table4[val][b1];
tcg_gen_addi_ptr(s->ptr0, cpu_env, op1_offset);