From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 19 Oct 2023 12:51:16 +0000 (+0200)
Subject: target/i386: do not decode string source/destination into decode->mem
X-Git-Tag: v9.0.0-rc0~125^2~34
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a71e0b246accc4dc11616580d7232fbf4b782dac;p=thirdparty%2Fqemu.git

target/i386: do not decode string source/destination into decode->mem

decode->mem is only used if one operand has has_ea == true.  String
operations will not use decode->mem and will load A0 on their own, because
they are the only case of two memory operands in a single instruction.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.c.inc
index d7a86d96c0c..99d18d2871e 100644
--- a/target/i386/tcg/decode-new.c.inc
+++ b/target/i386/tcg/decode-new.c.inc
@@ -1212,6 +1212,8 @@ static bool decode_op(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode,
     case X86_TYPE_None:  /* Implicit or absent */
     case X86_TYPE_A:  /* Implicit */
     case X86_TYPE_F:  /* EFLAGS/RFLAGS */
+    case X86_TYPE_X:  /* string source */
+    case X86_TYPE_Y:  /* string destination */
         break;
 
     case X86_TYPE_B:  /* VEX.vvvv selects a GPR */
@@ -1346,24 +1348,6 @@ static bool decode_op(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode,
         op->n = insn_get(env, s, op->ot) >> 4;
         break;
 
-    case X86_TYPE_X:  /* string source */
-        op->n = -1;
-        decode->mem = (AddressParts) {
-            .def_seg = R_DS,
-            .base = R_ESI,
-            .index = -1,
-        };
-        break;
-
-    case X86_TYPE_Y:  /* string destination */
-        op->n = -1;
-        decode->mem = (AddressParts) {
-            .def_seg = R_ES,
-            .base = R_EDI,
-            .index = -1,
-        };
-        break;
-
     case X86_TYPE_2op:
         *op = decode->op[0];
         break;