target/i386: Return bool from disas_insn

Instead of returning the new pc, which is present in
DisasContext, return true if an insn was translated.
This is false when we detect a page crossing and must
undo the insn under translation.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20221001140935.465607-3-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 24 insertions, 22 deletions

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 16bf56d..3f3e79c 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -4707,7 +4707,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, int b)
 
 /* convert one instruction. s->base.is_jmp is set if the translation must
    be stopped. Return the next pc value */
-static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
+static bool disas_insn(DisasContext *s, CPUState *cpu)
 {
     CPUX86State *env = cpu->env_ptr;
     int b, prefixes;
@@ -4734,15 +4734,16 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
         break;
     case 1:
         gen_exception_gpf(s);
-        return s->pc;
+        return true;
     case 2:
         /* Restore state that may affect the next instruction. */
+        s->pc = s->base.pc_next;
         s->cc_op_dirty = orig_cc_op_dirty;
         s->cc_op = orig_cc_op;
         s->base.num_insns--;
         tcg_remove_ops_after(s->prev_insn_end);
         s->base.is_jmp = DISAS_TOO_MANY;
-        return s->base.pc_next;
+        return false;
     default:
         g_assert_not_reached();
     }
@@ -8644,13 +8645,13 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
     default:
         goto unknown_op;
     }
-    return s->pc;
+    return true;
  illegal_op:
     gen_illegal_opcode(s);
-    return s->pc;
+    return true;
  unknown_op:
     gen_unknown_opcode(env, s);
-    return s->pc;
+    return true;
 }
 
 void tcg_x86_init(void)
@@ -8815,7 +8816,6 @@ static void i386_tr_insn_start(DisasContextBase *dcbase, CPUState *cpu)
 static void i386_tr_translate_insn(DisasContextBase *dcbase, CPUState *cpu)
 {
     DisasContext *dc = container_of(dcbase, DisasContext, base);
-    target_ulong pc_next;
 
 #ifdef TARGET_VSYSCALL_PAGE
     /*
@@ -8828,21 +8828,23 @@ static void i386_tr_translate_insn(DisasContextBase *dcbase, CPUState *cpu)
     }
 #endif
 
-    pc_next = disas_insn(dc, cpu);
-    dc->base.pc_next = pc_next;
-
-    if (dc->base.is_jmp == DISAS_NEXT) {
-        if (dc->flags & (HF_TF_MASK | HF_INHIBIT_IRQ_MASK)) {
-            /*
-             * If single step mode, we generate only one instruction and
-             * generate an exception.
-             * If irq were inhibited with HF_INHIBIT_IRQ_MASK, we clear
-             * the flag and abort the translation to give the irqs a
-             * chance to happen.
-             */
-            dc->base.is_jmp = DISAS_TOO_MANY;
-        } else if (!is_same_page(&dc->base, pc_next)) {
-            dc->base.is_jmp = DISAS_TOO_MANY;
+    if (disas_insn(dc, cpu)) {
+        target_ulong pc_next = dc->pc;
+        dc->base.pc_next = pc_next;
+
+        if (dc->base.is_jmp == DISAS_NEXT) {
+            if (dc->flags & (HF_TF_MASK | HF_INHIBIT_IRQ_MASK)) {
+                /*
+                 * If single step mode, we generate only one instruction and
+                 * generate an exception.
+                 * If irq were inhibited with HF_INHIBIT_IRQ_MASK, we clear
+                 * the flag and abort the translation to give the irqs a
+                 * chance to happen.
+                 */
+                dc->base.is_jmp = DISAS_TOO_MANY;
+            } else if (!is_same_page(&dc->base, pc_next)) {
+                dc->base.is_jmp = DISAS_TOO_MANY;
+            }
         }
     }
 }