From 46b4c104c2447d9081122696a43094d0cb987de3 Mon Sep 17 00:00:00 2001 From: Michael Pavone Date: Tue, 28 Apr 2015 19:04:36 -0700 Subject: Fix bug in map_native_address that was breaking some self-modifying code in Gunstar Heroes --- gen_x86.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'gen_x86.c') diff --git a/gen_x86.c b/gen_x86.c index 7531cd9..ef5fbe5 100644 --- a/gen_x86.c +++ b/gen_x86.c @@ -2135,9 +2135,15 @@ uint32_t x86_inst_size(code_ptr start) 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 { } -- cgit v1.2.3