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diff gen_x86.c @ 692:e11e68918691

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Fix bug in map_native_address that was breaking some self-modifying code in Gunstar Heroes
author Michael Pavone <pavone@retrodev.com>
date Tue, 28 Apr 2015 19:04:36 -0700
parents 74d636e85bf8
children cb1c005880e7
line wrap: on
line diff
--- a/gen_x86.c	Sat Mar 14 12:05:03 2015 -0700
+++ b/gen_x86.c	Tue Apr 28 19:04:36 2015 -0700
@@ -2135,9 +2135,15 @@
 	if (has_modrm(prefix, main_op)) {
 		uint8_t mod_rm = *(code++);
 		if (has_sib(mod_rm)) {
-			uint8_t sib = *(code++);
-		} else {
-
+			//sib takes up a byte, but can't add any additional ones beyond that
+			code++;
+		}
+		uint8_t mode = mod_rm & 0xC0;
+		uint8_t rm = mod_rm & 3;
+		if (mode == MODE_REG_DISPLACE8) {
+			code++;
+		} else if (mode == MODE_REG_DISPLACE32 || (mode == MODE_REG_INDIRECT && rm == RBP)) {
+			code += 4;
 		}
 	} else {
 	}