From 8bb4226f07b1e9ee79f3429a1495eaa694b13334 Mon Sep 17 00:00:00 2001 From: Michael Smith Date: Fri, 6 Sep 2024 21:55:42 +0100 Subject: Fix more broken x86 cases Thanks Evan Lin for reporting. --- src/x86.c | 3 ++- src/x86.h | 4 ++-- test/x86.test.c | 42 +++++++++++++++++++++++------------------- 3 files changed, 27 insertions(+), 22 deletions(-) diff --git a/src/x86.c b/src/x86.c index 7a5d00e..e0431d6 100644 --- a/src/x86.c +++ b/src/x86.c @@ -1,5 +1,5 @@ /* - * Copyright © 2023 Michael Smith + * Copyright © 2024 Michael Smith * * Permission to use, copy, modify, and/or distribute this software for any * purpose with or without fee is hereby granted, provided that the above @@ -25,6 +25,7 @@ static int mrmsib(const uchar *p, int addrlen) { // But it's confusingly-written enough that the code I wrote before didn't // work, so with any luck nobody will need to refer to it again and this is // actually correct now. Fingers crossed. + if ((*p & 0xC6) == 0x06) return 3; // special case for disp16 if (addrlen == 4 || *p & 0xC0) { int sib = addrlen == 4 && *p < 0xC0 && (*p & 7) == 4; switch (*p & 0xC0) { diff --git a/src/x86.h b/src/x86.h index a62c0ee..52e4f9b 100644 --- a/src/x86.h +++ b/src/x86.h @@ -143,8 +143,6 @@ X(X86_XORALI, 0x34) \ X(X86_CMPALI, 0x3C) \ X(X86_PUSHI8, 0x6A) \ - X(X86_MOVALII, 0xA0) /* From offset (indirect) */ \ - X(X86_MOVIIAL, 0xA2) /* To offset (indirect) */ \ X(X86_TESTALI, 0xA8) \ X(X86_JO, 0x70) \ X(X86_JNO, 0x71) \ @@ -190,7 +188,9 @@ X(X86_XOREAXI, 0x35) \ X(X86_CMPEAXI, 0x3D) \ X(X86_PUSHIW, 0x68) \ + X(X86_MOVALII, 0xA0) /* From offset (indirect) */ \ X(X86_MOVEAXII, 0xA1) /* From offset (indirect) */ \ + X(X86_MOVIIAL, 0xA2) /* To offset (indirect) */ \ X(X86_MOVIIEAX, 0xA3) /* To offset (indirect) */ \ X(X86_TESTEAXI, 0xA9) \ X(X86_MOVEAXI, 0xB8) \ diff --git a/test/x86.test.c b/test/x86.test.c index ab0a679..c0c825a 100644 --- a/test/x86.test.c +++ b/test/x86.test.c @@ -5,25 +5,15 @@ #include "../src/x86.c" #include "../src/intdefs.h" +#include "../src/ppmagic.h" + TEST("The \"crazy\" instructions should be given correct lengths\n") { - const uchar test8[] = { - 0xF6, 0x05, 0x12, 0x34, 0x56, 0x78, 0x12 - }; - const uchar test16[] = { - 0x66, 0xF7, 0x05, 0x12, 0x34, 0x56, 0x78, 0x12, 0x34 - }; - const uchar test32[] = { - 0xF7, 0x05, 0x12, 0x34, 0x56, 0x78, 0x12, 0x34, 0x56, 0x78 - }; - const uchar not8[] = { - 0xF6, 0x15, 0x12, 0x34, 0x56, 0x78 - }; - const uchar not16[] = { - 0x66, 0xF7, 0x15, 0x12, 0x34, 0x56, 0x78 - }; - const uchar not32[] = { - 0xF7, 0x15, 0x12, 0x34, 0x56, 0x78 - }; + const uchar test8[] = HEXBYTES(F6, 05, 12, 34, 56, 78, 12); + const uchar test16[] = HEXBYTES(66, F7, 05, 12, 34, 56, 78, 12, 34); + const uchar test32[] = HEXBYTES(F7, 05, 12, 34, 56, 78, 12, 34, 56, 78); + const uchar not8[] = HEXBYTES(F6, 15, 12, 34, 56, 78); + const uchar not16[] = HEXBYTES(66, F7, 15, 12, 34, 56, 78); + const uchar not32[] = HEXBYTES(F7, 15, 12, 34, 56, 78); if (x86_len(test8) != 7) return false; if (x86_len(test16) != 9) return false; if (x86_len(test32) != 10) return false; @@ -34,8 +24,22 @@ TEST("The \"crazy\" instructions should be given correct lengths\n") { } TEST("SIB bytes should be decoded correctly") { - const uchar fstp[] = {0xD9, 0x1C, 0x24}; // old buggy case, for regressions + const uchar fstp[] = HEXBYTES(D9, 1C, 24); // old buggy case for regressions return x86_len(fstp) == 3; } +TEST("mov AL, moff8 instructions should be decoded correctly") { + // more fixed buggy cases for regressions + const uchar mov_moff8_al[] = HEXBYTES(A2, DA, 78, B4, 0D); + const uchar mov_al_moff8[] = HEXBYTES(A0, 28, DF, 5C, 66); + if (x86_len(mov_moff8_al) != 5) return false; + if (x86_len(mov_al_moff8) != 5) return false; + return true; +} + +TEST("fiadd [off16] instructions should be decoded correctly") { + const uchar fiadd_off16[] = HEXBYTES(67, DA, 06, DF, 11); + return x86_len(fiadd_off16) == 5; +} + // vi: sw=4 ts=4 noet tw=80 cc=80 -- cgit v1.2.3