target-i386: emulate LOCK'ed OP instructions using atomic helpers

[rth: Eliminate some unnecessary temporaries.]
Signed-off-by: NEmilio G. Cota <cota@braap.org>
Message-Id: <1467054136-10430-13-git-send-email-cota@braap.org>
Signed-off-by: NRichard Henderson <rth@twiddle.net>

target-i386/translate.c

@@ -1257,55 +1257,95 @@ static void gen_op(DisasContext *s1, int op, TCGMemOp ot, int d)
 {
     if (d != OR_TMP0) {
         gen_op_mov_v_reg(ot, cpu_T0, d);
-    } else {
+    } else if (!(s1->prefix & PREFIX_LOCK)) {
         gen_op_ld_v(s1, ot, cpu_T0, cpu_A0);
     }
     switch(op) {
     case OP_ADCL:
         gen_compute_eflags_c(s1, cpu_tmp4);
-        tcg_gen_add_tl(cpu_T0, cpu_T0, cpu_T1);
-        tcg_gen_add_tl(cpu_T0, cpu_T0, cpu_tmp4);
-        gen_op_st_rm_T0_A0(s1, ot, d);
+        if (s1->prefix & PREFIX_LOCK) {
+            tcg_gen_add_tl(cpu_T0, cpu_tmp4, cpu_T1);
+            tcg_gen_atomic_add_fetch_tl(cpu_T0, cpu_A0, cpu_T0,
+                                        s1->mem_index, ot | MO_LE);
+        } else {
+            tcg_gen_add_tl(cpu_T0, cpu_T0, cpu_T1);
+            tcg_gen_add_tl(cpu_T0, cpu_T0, cpu_tmp4);
+            gen_op_st_rm_T0_A0(s1, ot, d);
+        }
         gen_op_update3_cc(cpu_tmp4);
         set_cc_op(s1, CC_OP_ADCB + ot);
         break;
     case OP_SBBL:
         gen_compute_eflags_c(s1, cpu_tmp4);
-        tcg_gen_sub_tl(cpu_T0, cpu_T0, cpu_T1);
-        tcg_gen_sub_tl(cpu_T0, cpu_T0, cpu_tmp4);
-        gen_op_st_rm_T0_A0(s1, ot, d);
+        if (s1->prefix & PREFIX_LOCK) {
+            tcg_gen_add_tl(cpu_T0, cpu_T1, cpu_tmp4);
+            tcg_gen_neg_tl(cpu_T0, cpu_T0);
+            tcg_gen_atomic_add_fetch_tl(cpu_T0, cpu_A0, cpu_T0,
+                                        s1->mem_index, ot | MO_LE);
+        } else {
+            tcg_gen_sub_tl(cpu_T0, cpu_T0, cpu_T1);
+            tcg_gen_sub_tl(cpu_T0, cpu_T0, cpu_tmp4);
+            gen_op_st_rm_T0_A0(s1, ot, d);
+        }
         gen_op_update3_cc(cpu_tmp4);
         set_cc_op(s1, CC_OP_SBBB + ot);
         break;
     case OP_ADDL:
-        tcg_gen_add_tl(cpu_T0, cpu_T0, cpu_T1);
-        gen_op_st_rm_T0_A0(s1, ot, d);
+        if (s1->prefix & PREFIX_LOCK) {
+            tcg_gen_atomic_add_fetch_tl(cpu_T0, cpu_A0, cpu_T1,
+                                        s1->mem_index, ot | MO_LE);
+        } else {
+            tcg_gen_add_tl(cpu_T0, cpu_T0, cpu_T1);
+            gen_op_st_rm_T0_A0(s1, ot, d);
+        }
         gen_op_update2_cc();
         set_cc_op(s1, CC_OP_ADDB + ot);
         break;
     case OP_SUBL:
-        tcg_gen_mov_tl(cpu_cc_srcT, cpu_T0);
-        tcg_gen_sub_tl(cpu_T0, cpu_T0, cpu_T1);
-        gen_op_st_rm_T0_A0(s1, ot, d);
+        if (s1->prefix & PREFIX_LOCK) {
+            tcg_gen_neg_tl(cpu_T0, cpu_T1);
+            tcg_gen_atomic_fetch_add_tl(cpu_cc_srcT, cpu_A0, cpu_T0,
+                                        s1->mem_index, ot | MO_LE);
+            tcg_gen_sub_tl(cpu_T0, cpu_cc_srcT, cpu_T1);
+        } else {
+            tcg_gen_mov_tl(cpu_cc_srcT, cpu_T0);
+            tcg_gen_sub_tl(cpu_T0, cpu_T0, cpu_T1);
+            gen_op_st_rm_T0_A0(s1, ot, d);
+        }
         gen_op_update2_cc();
         set_cc_op(s1, CC_OP_SUBB + ot);
         break;
     default:
     case OP_ANDL:
-        tcg_gen_and_tl(cpu_T0, cpu_T0, cpu_T1);
-        gen_op_st_rm_T0_A0(s1, ot, d);
+        if (s1->prefix & PREFIX_LOCK) {
+            tcg_gen_atomic_and_fetch_tl(cpu_T0, cpu_A0, cpu_T1,
+                                        s1->mem_index, ot | MO_LE);
+        } else {
+            tcg_gen_and_tl(cpu_T0, cpu_T0, cpu_T1);
+            gen_op_st_rm_T0_A0(s1, ot, d);
+        }
         gen_op_update1_cc();
         set_cc_op(s1, CC_OP_LOGICB + ot);
         break;
     case OP_ORL:
-        tcg_gen_or_tl(cpu_T0, cpu_T0, cpu_T1);
-        gen_op_st_rm_T0_A0(s1, ot, d);
+        if (s1->prefix & PREFIX_LOCK) {
+            tcg_gen_atomic_or_fetch_tl(cpu_T0, cpu_A0, cpu_T1,
+                                       s1->mem_index, ot | MO_LE);
+        } else {
+            tcg_gen_or_tl(cpu_T0, cpu_T0, cpu_T1);
+            gen_op_st_rm_T0_A0(s1, ot, d);
+        }
         gen_op_update1_cc();
         set_cc_op(s1, CC_OP_LOGICB + ot);
         break;
     case OP_XORL:
-        tcg_gen_xor_tl(cpu_T0, cpu_T0, cpu_T1);
-        gen_op_st_rm_T0_A0(s1, ot, d);
+        if (s1->prefix & PREFIX_LOCK) {
+            tcg_gen_atomic_xor_fetch_tl(cpu_T0, cpu_A0, cpu_T1,
+                                        s1->mem_index, ot | MO_LE);
+        } else {
+            tcg_gen_xor_tl(cpu_T0, cpu_T0, cpu_T1);
+            gen_op_st_rm_T0_A0(s1, ot, d);
+        }
         gen_op_update1_cc();
         set_cc_op(s1, CC_OP_LOGICB + ot);
         break;