From f8e2d3f8eaedf4947a36ad1cff104471eff1225b Mon Sep 17 00:00:00 2001
From: clc5q <clc5q@git.zephyr-software.com>
Date: Wed, 5 Mar 2008 02:16:22 +0000
Subject: [PATCH] Handle DEFs/USEs due to REP/REPNE prefixes.
---
SMPInstr.cpp | 29 ++++++++++++++++++++++++++---
1 file changed, 26 insertions(+), 3 deletions(-)
diff --git a/SMPInstr.cpp b/SMPInstr.cpp
index b47df897..5e006be9 100644
--- a/SMPInstr.cpp
+++ b/SMPInstr.cpp
@@ -582,11 +582,34 @@ void SMPInstr::MDFixupDefUseLists(void) {
} // end if (o_phrase or o_displ operand)
} // end for (all operands)
- // Next, handle repeat prefices in the instructions.
+ // Next, handle repeat prefices in the instructions. The Intel REPE/REPZ prefix
+ // is just the text printed for SCAS/CMPS instructions that have a REP prefix.
+ // Only two distinct prefix codes are actually defined: REP and REPNE/REPNZ, and
+ // REPNE/REPNZ only applies to SCAS and CMPS instructions.
bool HasRepPrefix = (0 != (this->SMPcmd.auxpref & aux_rep));
bool HasRepnePrefix = (0 != (this->SMPcmd.auxpref & aux_repne));
if (HasRepPrefix && HasRepnePrefix)
msg("REP and REPNE both present at %x %s\n", this->GetAddr(), this->GetDisasm());
+ if (HasRepPrefix || HasRepnePrefix) {
+ // All repeating instructions use ECX as the countdown register.
+ op_t BaseOpnd;
+ BaseOpnd.type = o_reg; // Change type and reg fields
+ BaseOpnd.reg = R_cx;
+ BaseOpnd.hasSIB = 0;
+ BaseOpnd.clr_showed();
+ this->Defs.SetRef(BaseOpnd);
+ this->Uses.SetRef(BaseOpnd);
+ }
+ if (!this->DefsFlags && ((this->SMPcmd.itype == NN_cmps) || (this->SMPcmd.itype == NN_scas))) {
+ // REPE and REPNE define the flags in addition to ECX.
+ op_t BaseOpnd;
+ BaseOpnd.type = o_reg; // Change type and reg fields
+ BaseOpnd.reg = X86_FLAGS_REG;
+ BaseOpnd.hasSIB = 0;
+ BaseOpnd.clr_showed();
+ this->Defs.SetRef(BaseOpnd);
+ this->DefsFlags = true;
+ }
// Now, handle special instruction categories that have implicit operands.
if (NN_cmpxchg == this->SMPcmd.itype) {
@@ -640,11 +663,11 @@ void SMPInstr::MDFixupDefUseLists(void) {
if (this->type == COND_BRANCH) {
assert(SMPUsesFlags[this->SMPcmd.itype]);
}
- if (SMPDefsFlags[this->SMPcmd.itype]) {
+ if (!this->DefsFlags && SMPDefsFlags[this->SMPcmd.itype]) {
this->MDAddRegDef(X86_FLAGS_REG, false);
this->DefsFlags = true;
}
- if (SMPUsesFlags[this->SMPcmd.itype]) {
+ if (!this->UsesFlags && SMPUsesFlags[this->SMPcmd.itype]) {
this->MDAddRegUse(X86_FLAGS_REG, false);
this->UsesFlags = true;
}
--
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