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[PATCH] target/i386: tcg: high bits SSE cmp operation must be ignored
From: |
Paolo Bonzini |
Subject: |
[PATCH] target/i386: tcg: high bits SSE cmp operation must be ignored |
Date: |
Thu, 24 Mar 2022 09:08:47 +0100 |
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>
---
target/i386/tcg/translate.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 2a94d33742..c393913fe0 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -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);
--
2.35.1
- [PATCH] target/i386: tcg: high bits SSE cmp operation must be ignored,
Paolo Bonzini <=