diff --git a/disasm.c b/disasm.c index 05598839..49c3051a 100644 --- a/disasm.c +++ b/disasm.c @@ -406,18 +406,24 @@ static uint8_t *do_ea(uint8_t *data, int modrm, int asize, if (rm == 4) { /* process SIB */ + uint8_t vsib_hi = 0; scale = (sib >> 6) & 03; index = (sib >> 3) & 07; base = sib & 07; op->scale = 1 << scale; + if (segsize == 64) { + vsib_hi = (rex & REX_X ? 8 : 0) | + (evex[2] & EVEX_P2VP ? 0 : 16); + } + if (type == EA_XMMVSIB) - op->indexreg = nasm_rd_xmmreg[index | ((rex & REX_X) ? 8 : 0)]; + op->indexreg = nasm_rd_xmmreg[index | vsib_hi]; else if (type == EA_YMMVSIB) - op->indexreg = nasm_rd_ymmreg[index | ((rex & REX_X) ? 8 : 0)]; + op->indexreg = nasm_rd_ymmreg[index | vsib_hi]; else if (type == EA_ZMMVSIB) - op->indexreg = nasm_rd_zmmreg[index | ((rex & REX_X) ? 8 : 0)]; + op->indexreg = nasm_rd_zmmreg[index | vsib_hi]; else if (index == 4 && !(rex & REX_X)) op->indexreg = -1; /* ESP/RSP cannot be an index */ else if (a64) @@ -749,7 +755,9 @@ static int matches(const struct itemplate *t, uint8_t *data, return false; if (c == 0250) { - if ((prefix->vex_v != 0) || !(prefix->evex[2] & EVEX_P2VP)) + if ((prefix->vex_v != 0) || + (!(prefix->evex[2] & EVEX_P2VP) && + ((eat < EA_XMMVSIB) || (eat > EA_ZMMVSIB)))) return false; } else { opx->segment |= SEG_RMREG;