http://llvm.org/bugs/show_bug.cgi?id=20252
Bug ID: 20252
Summary: Incorrect disassembly of X86 INT opcode
Product: libraries
Version: trunk
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: Backend: X86
Assignee: [email protected]
Reporter: [email protected]
CC: [email protected]
Classification: Unclassified
The destination operand of x86 INT n opcode specifies an interrupt vector
number from 0 to 255, encoded as an 8-bit unsigned intermediate value. The X86
disassembler of LLVM treats the 8-bit value as a sign-extend value.
I think the following code:
static void translateImmediate(MCInst &mcInst, uint64_t immediate,
const OperandSpecifier &operand,
InternalInstruction &insn,
const MCDisassembler *Dis) {
...
case ENCODING_IB:
// Special case those X86 instructions that use the imm8 as a set of
// bits, bit count, etc. and are not sign-extend.
if (Opcode != X86::BLENDPSrri && Opcode != X86::BLENDPDrri &&
Opcode != X86::PBLENDWrri && Opcode != X86::MPSADBWrri &&
Opcode != X86::DPPSrri && Opcode != X86::DPPDrri &&
Opcode != X86::INSERTPSrr && Opcode != X86::VBLENDPSYrri &&
Opcode != X86::VBLENDPSYrmi && Opcode != X86::VBLENDPDYrri &&
Opcode != X86::VBLENDPDYrmi && Opcode != X86::VPBLENDWrri &&
Opcode != X86::VMPSADBWrri && Opcode != X86::VDPPSYrri &&
Opcode != X86::VDPPSYrmi && Opcode != X86::VDPPDrri &&
Opcode != X86::VINSERTPSrr)
...
}
should be changed to:
static void translateImmediate(MCInst &mcInst, uint64_t immediate,
const OperandSpecifier &operand,
InternalInstruction &insn,
const MCDisassembler *Dis) {
...
case ENCODING_IB:
// Special case those X86 instructions that use the imm8 as a set of
// bits, bit count, etc. and are not sign-extend.
if (Opcode != X86::BLENDPSrri && Opcode != X86::BLENDPDrri &&
Opcode != X86::PBLENDWrri && Opcode != X86::MPSADBWrri &&
Opcode != X86::DPPSrri && Opcode != X86::DPPDrri &&
Opcode != X86::INSERTPSrr && Opcode != X86::VBLENDPSYrri &&
Opcode != X86::VBLENDPSYrmi && Opcode != X86::VBLENDPDYrri &&
Opcode != X86::VBLENDPDYrmi && Opcode != X86::VPBLENDWrri &&
Opcode != X86::VMPSADBWrri && Opcode != X86::VDPPSYrri &&
Opcode != X86::VDPPSYrmi && Opcode != X86::VDPPDrri &&
Opcode != X86::VINSERTPSrr && Opcode !=X86::INT)
...
}
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
LLVMbugs mailing list
[email protected]
http://lists.cs.uiuc.edu/mailman/listinfo/llvmbugs
