diff --git a/target-i386/translate.c b/target-i386/translate.c
index 1988dae..d056842 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -7465,8 +7465,12 @@ static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
             gen_exception(s, EXCP0D_GPF, pc_start - s->cs_base);
         } else {
             modrm = ldub_code(s->pc++);
-            if ((modrm & 0xc0) != 0xc0)
-                goto illegal_op;
+            /* Ignore the mod bits (assume (modrm&0xc0)==0xc0).
+             * The 80386 reference manual says the bits are
+             * always 1, and doesn't say what happens if they aren't.
+             * But testing shows that the bits are just assumed to be
+             * 1s.
+             */
             rm = (modrm & 7) | REX_B(s);
             reg = ((modrm >> 3) & 7) | rex_r;
             if (CODE64(s))
@@ -7507,8 +7511,12 @@ static target_ulong disas_insn(DisasContext *s, target_ulong pc_start)
             gen_exception(s, EXCP0D_GPF, pc_start - s->cs_base);
         } else {
             modrm = ldub_code(s->pc++);
-            if ((modrm & 0xc0) != 0xc0)
-                goto illegal_op;
+            /* Ignore the mod bits (assume (modrm&0xc0)==0xc0).
+             * The 80386 reference manual says the bits are
+             * always 1, and doesn't say what happens if they aren't.
+             * But testing shows that the bits are just assumed to be
+             * 1s.
+             */
             rm = (modrm & 7) | REX_B(s);
             reg = ((modrm >> 3) & 7) | rex_r;
             if (CODE64(s))