[Qemu-devel] [RFC 14/30] target-i386: emulate LOCK'ed NOT using atomic helper

[Emilio G. Cota]

Signed-off-by: Emilio G. Cota <address@hidden>
---
 target-i386/translate.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/target-i386/translate.c b/target-i386/translate.c
index a9fa25a..fcccb1a 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -4784,11 +4784,19 @@ static target_ulong disas_insn(CPUX86State *env, 
DisasContext *s,
             set_cc_op(s, CC_OP_LOGICB + ot);
             break;
         case 2: /* not */
-            tcg_gen_not_tl(cpu_T0, cpu_T0);
-            if (mod != 3) {
-                gen_op_st_v(s, ot, cpu_T0, cpu_A0);
+            if (s->prefix & PREFIX_LOCK) {
+                if (mod == 3) {
+                    goto illegal_op;
+                }
+                tcg_gen_movi_tl(cpu_T0, ~0);
+                gen_atomic_xor_fetch(cpu_T0, cpu_A0, cpu_T0, ot);
             } else {
-                gen_op_mov_reg_v(ot, rm, cpu_T0);
+                tcg_gen_not_tl(cpu_T0, cpu_T0);
+                if (mod != 3) {
+                    gen_op_st_v(s, ot, cpu_T0, cpu_A0);
+                } else {
+                    gen_op_mov_reg_v(ot, rm, cpu_T0);
+                }
             }
             break;
         case 3: /* neg */
-- 
2.5.0