//===- ThumbDisassemblerCore.h - Thumb disassembler helpers -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file is part of the ARM Disassembler.
// It contains code for disassembling a Thumb instr. It is to be included by
// ARMDisassemblerCore.cpp because it contains the static DisassembleThumbFrm()
// function which acts as the dispatcher to disassemble a Thumb instruction.
//
//===----------------------------------------------------------------------===//
///////////////////////////////
// //
// Utility Functions //
// //
///////////////////////////////
// Utilities for 16-bit Thumb instructions.
/*
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
[ tRt ]
[ tRm ] [ tRn ] [ tRd ]
D [ Rm ] [ Rd ]
[ imm3]
[ imm5 ]
i [ imm5 ]
[ imm7 ]
[ imm8 ]
[ imm11 ]
[ cond ]
*/
// Extract tRt: Inst{10-8}.
static inline unsigned getT1tRt(uint32_t insn) {
return slice(insn, 10, 8);
}
// Extract tRm: Inst{8-6}.
static inline unsigned getT1tRm(uint32_t insn) {
return slice(insn, 8, 6);
}
// Extract tRn: Inst{5-3}.
static inline unsigned getT1tRn(uint32_t insn) {
return slice(insn, 5, 3);
}
// Extract tRd: Inst{2-0}.
static inline unsigned getT1tRd(uint32_t insn) {
return slice(insn, 2, 0);
}
// Extract [D:Rd]: Inst{7:2-0}.
static inline unsigned getT1Rd(uint32_t insn) {
return slice(insn, 7, 7) << 3 | slice(insn, 2, 0);
}
// Extract Rm: Inst{6-3}.
static inline unsigned getT1Rm(uint32_t insn) {
return slice(insn, 6, 3);
}
// Extract imm3: Inst{8-6}.
static inline unsigned getT1Imm3(uint32_t insn) {
return slice(insn, 8, 6);
}
// Extract imm5: Inst{10-6}.
static inline unsigned getT1Imm5(uint32_t insn) {
return slice(insn, 10, 6);
}
// Extract i:imm5: Inst{9:7-3}.
static inline unsigned getT1Imm6(uint32_t insn) {
return slice(insn, 9, 9) << 5 | slice(insn, 7, 3);
}
// Extract imm7: Inst{6-0}.
static inline unsigned getT1Imm7(uint32_t insn) {
return slice(insn, 6, 0);
}
// Extract imm8: Inst{7-0}.
static inline unsigned getT1Imm8(uint32_t insn) {
return slice(insn, 7, 0);
}
// Extract imm11: Inst{10-0}.
static inline unsigned getT1Imm11(uint32_t insn) {
return slice(insn, 10, 0);
}
// Extract cond: Inst{11-8}.
static inline unsigned getT1Cond(uint32_t insn) {
return slice(insn, 11, 8);
}
static inline bool IsGPR(unsigned RegClass) {
return RegClass == ARM::GPRRegClassID || RegClass == ARM::rGPRRegClassID;
}
// Utilities for 32-bit Thumb instructions.
static inline bool BadReg(uint32_t n) { return n == 13 || n == 15; }
// Extract imm4: Inst{19-16}.
static inline unsigned getImm4(uint32_t insn) {
return slice(insn, 19, 16);
}
// Extract imm3: Inst{14-12}.
static inline unsigned getImm3(uint32_t insn) {
return slice(insn, 14, 12);
}
// Extract imm8: Inst{7-0}.
static inline unsigned getImm8(uint32_t insn) {
return slice(insn, 7, 0);
}
// A8.6.61 LDRB (immediate, Thumb) and friends
// +/-: Inst{9}
// imm8: Inst{7-0}
static inline int decodeImm8(uint32_t insn) {
int Offset = getImm8(insn);
return slice(insn, 9, 9) ? Offset : -Offset;
}
// Extract imm12: Inst{11-0}.
static inline unsigned getImm12(uint32_t insn) {
return slice(insn, 11, 0);
}
// A8.6.63 LDRB (literal) and friends
// +/-: Inst{23}
// imm12: Inst{11-0}
static inline int decodeImm12(uint32_t insn) {
int Offset = getImm12(insn);
return slice(insn, 23, 23) ? Offset : -Offset;
}
// Extract imm2: Inst{7-6}.
static inline unsigned getImm2(uint32_t insn) {
return slice(insn, 7, 6);
}
// For BFI, BFC, t2SBFX, and t2UBFX.
// Extract lsb: Inst{14-12:7-6}.
static inline unsigned getLsb(uint32_t insn) {
return getImm3(insn) << 2 | getImm2(insn);
}
// For BFI and BFC.
// Extract msb: Inst{4-0}.
static inline unsigned getMsb(uint32_t insn) {
return slice(insn, 4, 0);
}
// For t2SBFX and t2UBFX.
// Extract widthminus1: Inst{4-0}.
static inline unsigned getWidthMinus1(uint32_t insn) {
return slice(insn, 4, 0);
}
// For t2ADDri12 and t2SUBri12.
// imm12 = i:imm3:imm8;
static inline unsigned getIImm3Imm8(uint32_t insn) {
return slice(insn, 26, 26) << 11 | getImm3(insn) << 8 | getImm8(insn);
}
// For t2MOVi16 and t2MOVTi16.
// imm16 = imm4:i:imm3:imm8;
static inline unsigned getImm16(uint32_t insn) {
return getImm4(insn) << 12 | slice(insn, 26, 26) << 11 |
getImm3(insn) << 8 | getImm8(insn);
}
// Inst{5-4} encodes the shift type.
static inline unsigned getShiftTypeBits(uint32_t insn) {
return slice(insn, 5, 4);
}
// Inst{14-12}:Inst{7-6} encodes the imm5 shift amount.
static inline unsigned getShiftAmtBits(uint32_t insn) {
return getImm3(insn) << 2 | getImm2(insn);
}
// A8.6.17 BFC
// Encoding T1 ARMv6T2, ARMv7
// LLVM-specific encoding for #<lsb> and #<width>
static inline bool getBitfieldInvMask(uint32_t insn, uint32_t &mask) {
uint32_t lsb = getImm3(insn) << 2 | getImm2(insn);
uint32_t msb = getMsb(insn);
uint32_t Val = 0;
if (msb < lsb) {
DEBUG(errs() << "Encoding error: msb < lsb\n");
return false;
}
for (uint32_t i = lsb; i <= msb; ++i)
Val |= (1 << i);
mask = ~Val;
return true;
}
// A8.4 Shifts applied to a register
// A8.4.1 Constant shifts
// A8.4.3 Pseudocode details of instruction-specified shifts and rotates
//
// decodeImmShift() returns the shift amount and the the shift opcode.
// Note that, as of Jan-06-2010, LLVM does not support rrx shifted operands yet.
static inline unsigned decodeImmShift(unsigned bits2, unsigned imm5,
ARM_AM::ShiftOpc &ShOp) {
assert(imm5 < 32 && "Invalid imm5 argument");
switch (bits2) {
default: assert(0 && "No such value");
case 0:
ShOp = (imm5 == 0 ? ARM_AM::no_shift : ARM_AM::lsl);
return imm5;
case 1:
ShOp = ARM_AM::lsr;
return (imm5 == 0 ? 32 : imm5);
case 2:
ShOp = ARM_AM::asr;
return (imm5 == 0 ? 32 : imm5);
case 3:
ShOp = (imm5 == 0 ? ARM_AM::rrx : ARM_AM::ror);
return (imm5 == 0 ? 1 : imm5);
}
}
// A6.3.2 Modified immediate constants in Thumb instructions
//
// ThumbExpandImm() returns the modified immediate constant given an imm12 for
// Thumb data-processing instructions with modified immediate.
// See also A6.3.1 Data-processing (modified immediate).
static inline unsigned ThumbExpandImm(unsigned imm12) {
assert(imm12 <= 0xFFF && "Invalid imm12 argument");
// If the leading two bits is 0b00, the modified immediate constant is
// obtained by splatting the low 8 bits into the first byte, every other byte,
// or every byte of a 32-bit value.
//
// Otherwise, a rotate right of '1':imm12<6:0> by the amount imm12<11:7> is
// performed.
if (slice(imm12, 11, 10) == 0) {
unsigned short control = slice(imm12, 9, 8);
unsigned imm8 = slice(imm12, 7, 0);
switch (control) {
default:
assert(0 && "No such value");
return 0;
case 0:
return imm8;
case 1:
return imm8 << 16 | imm8;
case 2:
return imm8 << 24 | imm8 << 8;
case 3:
return imm8 << 24 | imm8 << 16 | imm8 << 8 | imm8;
}
} else {
// A rotate is required.
unsigned Val = 1 << 7 | slice(imm12, 6, 0);
unsigned Amt = slice(imm12, 11, 7);
return ARM_AM::rotr32(Val, Amt);
}
}
static inline int decodeImm32_B_EncodingT3(uint32_t insn) {
bool S = slice(insn, 26, 26);
bool J1 = slice(insn, 13, 13);
bool J2 = slice(insn, 11, 11);
unsigned Imm21 = slice(insn, 21, 16) << 12 | slice(insn, 10, 0) << 1;
if (S) Imm21 |= 1 << 20;
if (J2) Imm21 |= 1 << 19;
if (J1) Imm21 |= 1 << 18;
return SignExtend32<21>(Imm21);
}
static inline int decodeImm32_B_EncodingT4(uint32_t insn) {
unsigned S = slice(insn, 26, 26);
bool I1 = slice(insn, 13, 13) == S;
bool I2 = slice(insn, 11, 11) == S;
unsigned Imm25 = slice(insn, 25, 16) << 12 | slice(insn, 10, 0) << 1;
if (S) Imm25 |= 1 << 24;
if (I1) Imm25 |= 1 << 23;
if (I2) Imm25 |= 1 << 22;
return SignExtend32<25>(Imm25);
}
static inline int decodeImm32_BL(uint32_t insn) {
unsigned S = slice(insn, 26, 26);
bool I1 = slice(insn, 13, 13) == S;
bool I2 = slice(insn, 11, 11) == S;
unsigned Imm25 = slice(insn, 25, 16) << 12 | slice(insn, 10, 0) << 1;
if (S) Imm25 |= 1 << 24;
if (I1) Imm25 |= 1 << 23;
if (I2) Imm25 |= 1 << 22;
return SignExtend32<25>(Imm25);
}
static inline int decodeImm32_BLX(uint32_t insn) {
unsigned S = slice(insn, 26, 26);
bool I1 = slice(insn, 13, 13) == S;
bool I2 = slice(insn, 11, 11) == S;
unsigned Imm25 = slice(insn, 25, 16) << 12 | slice(insn, 10, 1) << 2;
if (S) Imm25 |= 1 << 24;
if (I1) Imm25 |= 1 << 23;
if (I2) Imm25 |= 1 << 22;
return SignExtend32<25>(Imm25);
}
// See, for example, A8.6.221 SXTAB16.
static inline unsigned decodeRotate(uint32_t insn) {
unsigned rotate = slice(insn, 5, 4);
return rotate << 3;
}
///////////////////////////////////////////////
// //
// Thumb1 instruction disassembly functions. //
// //
///////////////////////////////////////////////
// See "Utilities for 16-bit Thumb instructions" for register naming convention.
// A6.2.1 Shift (immediate), add, subtract, move, and compare
//
// shift immediate: tRd CPSR tRn imm5
// add/sub register: tRd CPSR tRn tRm
// add/sub 3-bit immediate: tRd CPSR tRn imm3
// add/sub 8-bit immediate: tRt CPSR tRt(TIED_TO) imm8
// mov/cmp immediate: tRt [CPSR] imm8 (CPSR present for mov)
//
// Special case:
// tMOVSr: tRd tRn
static bool DisassembleThumb1General(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID
&& "Invalid arguments");
bool Imm3 = (Opcode == ARM::tADDi3 || Opcode == ARM::tSUBi3);
// Use Rt implies use imm8.
bool UseRt = (Opcode == ARM::tADDi8 || Opcode == ARM::tSUBi8 ||
Opcode == ARM::tMOVi8 || Opcode == ARM::tCMPi8);
// Add the destination operand.
MI.addOperand(MCOperand::CreateReg(
getRegisterEnum(B, ARM::tGPRRegClassID,
UseRt ? getT1tRt(insn) : getT1tRd(insn))));
++OpIdx;
// Check whether the next operand to be added is a CCR Register.
if (OpInfo[OpIdx].RegClass == ARM::CCRRegClassID) {
assert(OpInfo[OpIdx].isOptionalDef() && "Optional def operand expected");
MI.addOperand(MCOperand::CreateReg(B->InITBlock() ? 0 : ARM::CPSR));
++OpIdx;
}
// Check whether the next operand to be added is a Thumb1 Register.
assert(OpIdx < NumOps && "More operands expected");
if (OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID) {
// For UseRt, the reg operand is tied to the first reg operand.
MI.addOperand(MCOperand::CreateReg(
getRegisterEnum(B, ARM::tGPRRegClassID,
UseRt ? getT1tRt(insn) : getT1tRn(insn))));
++OpIdx;
}
// Special case for tMOVSr.
if (OpIdx == NumOps)
return true;
// The next available operand is either a reg operand or an imm operand.
if (OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID) {
// Three register operand instructions.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRm(insn))));
} else {
assert(OpInfo[OpIdx].RegClass < 0 &&
!OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()
&& "Pure imm operand expected");
unsigned Imm = 0;
if (UseRt)
Imm = getT1Imm8(insn);
else if (Imm3)
Imm = getT1Imm3(insn);
else {
Imm = getT1Imm5(insn);
ARM_AM::ShiftOpc ShOp = getShiftOpcForBits(slice(insn, 12, 11));
getImmShiftSE(ShOp, Imm);
}
MI.addOperand(MCOperand::CreateImm(Imm));
}
++OpIdx;
return true;
}
// A6.2.2 Data-processing
//
// tCMPr, tTST, tCMN: tRd tRn
// tMVN, tRSB: tRd CPSR tRn
// Others: tRd CPSR tRd(TIED_TO) tRn
static bool DisassembleThumb1DP(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
(OpInfo[1].RegClass == ARM::CCRRegClassID
|| OpInfo[1].RegClass == ARM::tGPRRegClassID)
&& "Invalid arguments");
// Add the destination operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRd(insn))));
++OpIdx;
// Check whether the next operand to be added is a CCR Register.
if (OpInfo[OpIdx].RegClass == ARM::CCRRegClassID) {
assert(OpInfo[OpIdx].isOptionalDef() && "Optional def operand expected");
MI.addOperand(MCOperand::CreateReg(B->InITBlock() ? 0 : ARM::CPSR));
++OpIdx;
}
// We have either { tRd(TIED_TO), tRn } or { tRn } remaining.
// Process the TIED_TO operand first.
assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID
&& "Thumb reg operand expected");
int Idx;
if ((Idx = MCID.getOperandConstraint(OpIdx, MCOI::TIED_TO)) != -1) {
// The reg operand is tied to the first reg operand.
MI.addOperand(MI.getOperand(Idx));
++OpIdx;
}
// Process possible next reg operand.
if (OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID) {
// Add tRn operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRn(insn))));
++OpIdx;
}
return true;
}
// A6.2.3 Special data instructions and branch and exchange
//
// tADDhirr: Rd Rd(TIED_TO) Rm
// tCMPhir: Rd Rm
// tMOVr, tMOVgpr2gpr, tMOVgpr2tgpr, tMOVtgpr2gpr: Rd|tRd Rm|tRn
// tBX: Rm
// tBX_RET: 0 operand
// tBX_RET_vararg: Rm
// tBLXr: Rm
// tBRIND: Rm
static bool DisassembleThumb1Special(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
// tBX_RET has 0 operand.
if (NumOps == 0)
return true;
// BX/BLX/tBRIND (indirect branch, i.e, mov pc, Rm) has 1 reg operand: Rm.
if (Opcode==ARM::tBLXr || Opcode==ARM::tBX || Opcode==ARM::tBRIND) {
if (Opcode == ARM::tBLXr) {
// Handling the two predicate operands before the reg operand.
if (!B->DoPredicateOperands(MI, Opcode, insn, NumOps))
return false;
NumOpsAdded += 2;
}
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
getT1Rm(insn))));
NumOpsAdded += 1;
if (Opcode == ARM::tBX) {
// Handling the two predicate operands after the reg operand.
if (!B->DoPredicateOperands(MI, Opcode, insn, NumOps))
return false;
NumOpsAdded += 2;
}
return true;
}
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
// Add the destination operand.
unsigned RegClass = OpInfo[OpIdx].RegClass;
MI.addOperand(MCOperand::CreateReg(
getRegisterEnum(B, RegClass,
IsGPR(RegClass) ? getT1Rd(insn)
: getT1tRd(insn))));
++OpIdx;
// We have either { Rd(TIED_TO), Rm } or { Rm|tRn } remaining.
// Process the TIED_TO operand first.
assert(OpIdx < NumOps && "More operands expected");
int Idx;
if ((Idx = MCID.getOperandConstraint(OpIdx, MCOI::TIED_TO)) != -1) {
// The reg operand is tied to the first reg operand.
MI.addOperand(MI.getOperand(Idx));
++OpIdx;
}
// The next reg operand is either Rm or tRn.
assert(OpIdx < NumOps && "More operands expected");
RegClass = OpInfo[OpIdx].RegClass;
MI.addOperand(MCOperand::CreateReg(
getRegisterEnum(B, RegClass,
IsGPR(RegClass) ? getT1Rm(insn)
: getT1tRn(insn))));
++OpIdx;
return true;
}
// A8.6.59 LDR (literal)
//
// tLDRpci: tRt imm8*4
static bool DisassembleThumb1LdPC(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
(OpInfo[1].RegClass < 0 &&
!OpInfo[1].isPredicate() &&
!OpInfo[1].isOptionalDef())
&& "Invalid arguments");
// Add the destination operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRt(insn))));
// And the (imm8 << 2) operand.
MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn) << 2));
NumOpsAdded = 2;
return true;
}
// Thumb specific addressing modes (see ARMInstrThumb.td):
//
// t_addrmode_rr := reg + reg
//
// t_addrmode_s4 := reg + reg
// reg + imm5 * 4
//
// t_addrmode_s2 := reg + reg
// reg + imm5 * 2
//
// t_addrmode_s1 := reg + reg
// reg + imm5
//
// t_addrmode_sp := sp + imm8 * 4
//
// A8.6.63 LDRB (literal)
// A8.6.79 LDRSB (literal)
// A8.6.75 LDRH (literal)
// A8.6.83 LDRSH (literal)
// A8.6.59 LDR (literal)
//
// These instrs calculate an address from the PC value and an immediate offset.
// Rd Rn=PC (+/-)imm12 (+ if Inst{23} == 0b1)
static bool DisassembleThumb2Ldpci(MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps >= 2 &&
OpInfo[0].RegClass == ARM::GPRRegClassID &&
OpInfo[1].RegClass < 0 &&
"Expect >= 2 operands, first as reg, and second as imm operand");
// Build the register operand, followed by the (+/-)imm12 immediate.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRd(insn))));
MI.addOperand(MCOperand::CreateImm(decodeImm12(insn)));
NumOpsAdded = 2;
return true;
}
// A6.2.4 Load/store single data item
//
// Load/Store Register (reg|imm): tRd tRn imm5|tRm
// Load Register Signed Byte|Halfword: tRd tRn tRm
static bool DisassembleThumb1LdSt(unsigned opA, MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
assert(NumOps >= 2
&& OpInfo[0].RegClass == ARM::tGPRRegClassID
&& OpInfo[1].RegClass == ARM::tGPRRegClassID
&& "Expect >= 2 operands and first two as thumb reg operands");
// Add the destination reg and the base reg.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRd(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRn(insn))));
OpIdx = 2;
// We have either { imm5 } or { tRm } remaining.
// Note that STR/LDR (register) should skip the imm5 offset operand for
// t_addrmode_s[1|2|4].
assert(OpIdx < NumOps && "More operands expected");
if (OpInfo[OpIdx].RegClass < 0 && !OpInfo[OpIdx].isPredicate() &&
!OpInfo[OpIdx].isOptionalDef()) {
// Table A6-5 16-bit Thumb Load/store instructions
// opA = 0b0101 for STR/LDR (register) and friends.
// Otherwise, we have STR/LDR (immediate) and friends.
assert(opA != 5 && "Immediate operand expected for this opcode");
MI.addOperand(MCOperand::CreateImm(getT1Imm5(insn)));
++OpIdx;
} else {
// The next reg operand is tRm, the offset.
assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass == ARM::tGPRRegClassID
&& "Thumb reg operand expected");
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRm(insn))));
++OpIdx;
}
return true;
}
// A6.2.4 Load/store single data item
//
// Load/Store Register SP relative: tRt ARM::SP imm8
static bool DisassembleThumb1LdStSP(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
assert((Opcode == ARM::tLDRspi || Opcode == ARM::tSTRspi)
&& "Unexpected opcode");
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps >= 3 &&
OpInfo[0].RegClass == ARM::tGPRRegClassID &&
OpInfo[1].RegClass == ARM::GPRRegClassID &&
(OpInfo[2].RegClass < 0 &&
!OpInfo[2].isPredicate() &&
!OpInfo[2].isOptionalDef())
&& "Invalid arguments");
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRt(insn))));
MI.addOperand(MCOperand::CreateReg(ARM::SP));
MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn)));
NumOpsAdded = 3;
return true;
}
// Table A6-1 16-bit Thumb instruction encoding
// A8.6.10 ADR
//
// tADDrPCi: tRt imm8
static bool DisassembleThumb1AddPCi(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
assert(Opcode == ARM::tADDrPCi && "Unexpected opcode");
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
(OpInfo[1].RegClass < 0 &&
!OpInfo[1].isPredicate() &&
!OpInfo[1].isOptionalDef())
&& "Invalid arguments");
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRt(insn))));
MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn)));
NumOpsAdded = 2;
return true;
}
// Table A6-1 16-bit Thumb instruction encoding
// A8.6.8 ADD (SP plus immediate)
//
// tADDrSPi: tRt ARM::SP imm8
static bool DisassembleThumb1AddSPi(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
assert(Opcode == ARM::tADDrSPi && "Unexpected opcode");
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps >= 3 &&
OpInfo[0].RegClass == ARM::tGPRRegClassID &&
OpInfo[1].RegClass == ARM::GPRRegClassID &&
(OpInfo[2].RegClass < 0 &&
!OpInfo[2].isPredicate() &&
!OpInfo[2].isOptionalDef())
&& "Invalid arguments");
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRt(insn))));
MI.addOperand(MCOperand::CreateReg(ARM::SP));
MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn)));
NumOpsAdded = 3;
return true;
}
// tPUSH, tPOP: Pred-Imm Pred-CCR register_list
//
// where register_list = low registers + [lr] for PUSH or
// low registers + [pc] for POP
//
// "low registers" is specified by Inst{7-0}
// lr|pc is specified by Inst{8}
static bool DisassembleThumb1PushPop(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
assert((Opcode == ARM::tPUSH || Opcode == ARM::tPOP) && "Unexpected opcode");
unsigned &OpIdx = NumOpsAdded;
// Handling the two predicate operands before the reglist.
if (B->DoPredicateOperands(MI, Opcode, insn, NumOps))
OpIdx += 2;
else {
DEBUG(errs() << "Expected predicate operands not found.\n");
return false;
}
unsigned RegListBits = slice(insn, 8, 8) << (Opcode == ARM::tPUSH ? 14 : 15)
| slice(insn, 7, 0);
// Fill the variadic part of reglist.
for (unsigned i = 0; i < 16; ++i) {
if ((RegListBits >> i) & 1) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
i)));
++OpIdx;
}
}
return true;
}
// A6.2.5 Miscellaneous 16-bit instructions
// Delegate to DisassembleThumb1PushPop() for tPUSH & tPOP.
//
// tADDspi, tSUBspi: ARM::SP ARM::SP(TIED_TO) imm7
// t2IT: firstcond=Inst{7-4} mask=Inst{3-0}
// tCBNZ, tCBZ: tRd imm6*2
// tBKPT: imm8
// tNOP, tSEV, tYIELD, tWFE, tWFI:
// no operand (except predicate pair)
// tSETENDBE, tSETENDLE, :
// no operand
// Others: tRd tRn
static bool DisassembleThumb1Misc(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
if (NumOps == 0)
return true;
if (Opcode == ARM::tPUSH || Opcode == ARM::tPOP)
return DisassembleThumb1PushPop(MI, Opcode, insn, NumOps, NumOpsAdded, B);
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
// Predicate operands are handled elsewhere.
if (NumOps == 2 &&
OpInfo[0].isPredicate() && OpInfo[1].isPredicate() &&
OpInfo[0].RegClass < 0 && OpInfo[1].RegClass == ARM::CCRRegClassID) {
return true;
}
if (Opcode == ARM::tADDspi || Opcode == ARM::tSUBspi) {
// Special case handling for tADDspi and tSUBspi.
// A8.6.8 ADD (SP plus immediate) & A8.6.215 SUB (SP minus immediate)
MI.addOperand(MCOperand::CreateReg(ARM::SP));
MI.addOperand(MCOperand::CreateReg(ARM::SP));
MI.addOperand(MCOperand::CreateImm(getT1Imm7(insn)));
NumOpsAdded = 3;
return true;
}
if (Opcode == ARM::t2IT) {
// Special case handling for If-Then.
// A8.6.50 IT
// Tag the (firstcond[0] bit << 4) along with mask.
// firstcond
MI.addOperand(MCOperand::CreateImm(slice(insn, 7, 4)));
// firstcond[0] and mask
MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0)));
NumOpsAdded = 2;
return true;
}
if (Opcode == ARM::tBKPT) {
MI.addOperand(MCOperand::CreateImm(getT1Imm8(insn))); // breakpoint value
NumOpsAdded = 1;
return true;
}
// CPS has a singleton $opt operand that contains the following information:
// The first op would be 0b10 as enable and 0b11 as disable in regular ARM,
// but in Thumb it's is 0 as enable and 1 as disable. So map it to ARM's
// default one. The second get the AIF flags from Inst{2-0}.
if (Opcode == ARM::tCPS) {
MI.addOperand(MCOperand::CreateImm(2 + slice(insn, 4, 4)));
MI.addOperand(MCOperand::CreateImm(slice(insn, 2, 0)));
NumOpsAdded = 2;
return true;
}
assert(NumOps >= 2 && OpInfo[0].RegClass == ARM::tGPRRegClassID &&
(OpInfo[1].RegClass < 0 || OpInfo[1].RegClass==ARM::tGPRRegClassID)
&& "Expect >=2 operands");
// Add the destination operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRd(insn))));
if (OpInfo[1].RegClass == ARM::tGPRRegClassID) {
// Two register instructions.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
getT1tRn(insn))));
} else {
// CBNZ, CBZ
assert((Opcode == ARM::tCBNZ || Opcode == ARM::tCBZ) &&"Unexpected opcode");
MI.addOperand(MCOperand::CreateImm(getT1Imm6(insn) * 2));
}
NumOpsAdded = 2;
return true;
}
// A8.6.53 LDM / LDMIA
// A8.6.189 STM / STMIA
//
// tLDMIA_UPD/tSTMIA_UPD: tRt tRt AM4ModeImm Pred-Imm Pred-CCR register_list
// tLDMIA: tRt AM4ModeImm Pred-Imm Pred-CCR register_list
static bool DisassembleThumb1LdStMul(bool Ld, MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps,
unsigned &NumOpsAdded, BO B) {
assert((Opcode == ARM::tLDMIA || Opcode == ARM::tSTMIA) &&
"Unexpected opcode");
unsigned tRt = getT1tRt(insn);
NumOpsAdded = 0;
// WB register, if necessary.
if (Opcode == ARM::tLDMIA_UPD || Opcode == ARM::tSTMIA_UPD) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
tRt)));
++NumOpsAdded;
}
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
tRt)));
++NumOpsAdded;
// Handling the two predicate operands before the reglist.
if (B->DoPredicateOperands(MI, Opcode, insn, NumOps)) {
NumOpsAdded += 2;
} else {
DEBUG(errs() << "Expected predicate operands not found.\n");
return false;
}
unsigned RegListBits = slice(insn, 7, 0);
if (BitCount(RegListBits) < 1) {
DEBUG(errs() << "if BitCount(registers) < 1 then UNPREDICTABLE\n");
return false;
}
// Fill the variadic part of reglist.
for (unsigned i = 0; i < 8; ++i)
if ((RegListBits >> i) & 1) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::tGPRRegClassID,
i)));
++NumOpsAdded;
}
return true;
}
static bool DisassembleThumb1LdMul(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
return DisassembleThumb1LdStMul(true, MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
static bool DisassembleThumb1StMul(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
return DisassembleThumb1LdStMul(false, MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
// A8.6.16 B Encoding T1
// cond = Inst{11-8} & imm8 = Inst{7-0}
// imm32 = SignExtend(imm8:'0', 32)
//
// tBcc: offset Pred-Imm Pred-CCR
// tSVC: imm8 Pred-Imm Pred-CCR
// tTRAP: 0 operand (early return)
static bool DisassembleThumb1CondBr(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO) {
if (Opcode == ARM::tTRAP)
return true;
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps == 3 && OpInfo[0].RegClass < 0 &&
OpInfo[1].isPredicate() && OpInfo[2].RegClass == ARM::CCRRegClassID
&& "Exactly 3 operands expected");
unsigned Imm8 = getT1Imm8(insn);
MI.addOperand(MCOperand::CreateImm(
Opcode == ARM::tBcc ? SignExtend32<9>(Imm8 << 1)
: (int)Imm8));
// Predicate operands by ARMBasicMCBuilder::TryPredicateAndSBitModifier().
// But note that for tBcc, if cond = '1110' then UNDEFINED.
if (Opcode == ARM::tBcc && slice(insn, 11, 8) == 14) {
DEBUG(errs() << "if cond = '1110' then UNDEFINED\n");
return false;
}
NumOpsAdded = 1;
return true;
}
// A8.6.16 B Encoding T2
// imm11 = Inst{10-0}
// imm32 = SignExtend(imm11:'0', 32)
//
// tB: offset
static bool DisassembleThumb1Br(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps == 1 && OpInfo[0].RegClass < 0 && "1 imm operand expected");
unsigned Imm11 = getT1Imm11(insn);
MI.addOperand(MCOperand::CreateImm(SignExtend32<12>(Imm11 << 1)));
NumOpsAdded = 1;
return true;
}
// See A6.2 16-bit Thumb instruction encoding for instruction classes
// corresponding to op.
//
// Table A6-1 16-bit Thumb instruction encoding (abridged)
// op Instruction or instruction class
// ------ --------------------------------------------------------------------
// 00xxxx Shift (immediate), add, subtract, move, and compare on page A6-7
// 010000 Data-processing on page A6-8
// 010001 Special data instructions and branch and exchange on page A6-9
// 01001x Load from Literal Pool, see LDR (literal) on page A8-122
// 0101xx Load/store single data item on page A6-10
// 011xxx
// 100xxx
// 10100x Generate PC-relative address, see ADR on page A8-32
// 10101x Generate SP-relative address, see ADD (SP plus immediate) on
// page A8-28
// 1011xx Miscellaneous 16-bit instructions on page A6-11
// 11000x Store multiple registers, see STM / STMIA / STMEA on page A8-374
// 11001x Load multiple registers, see LDM / LDMIA / LDMFD on page A8-110 a
// 1101xx Conditional branch, and Supervisor Call on page A6-13
// 11100x Unconditional Branch, see B on page A8-44
//
static bool DisassembleThumb1(uint16_t op, MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
unsigned op1 = slice(op, 5, 4);
unsigned op2 = slice(op, 3, 2);
unsigned op3 = slice(op, 1, 0);
unsigned opA = slice(op, 5, 2);
switch (op1) {
case 0:
// A6.2.1 Shift (immediate), add, subtract, move, and compare
return DisassembleThumb1General(MI, Opcode, insn, NumOps, NumOpsAdded, B);
case 1:
switch (op2) {
case 0:
switch (op3) {
case 0:
// A6.2.2 Data-processing
return DisassembleThumb1DP(MI, Opcode, insn, NumOps, NumOpsAdded, B);
case 1:
// A6.2.3 Special data instructions and branch and exchange
return DisassembleThumb1Special(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
default:
// A8.6.59 LDR (literal)
return DisassembleThumb1LdPC(MI, Opcode, insn, NumOps, NumOpsAdded, B);
}
break;
default:
// A6.2.4 Load/store single data item
return DisassembleThumb1LdSt(opA, MI, Opcode, insn, NumOps, NumOpsAdded,
B);
break;
}
break;
case 2:
switch (op2) {
case 0:
// A6.2.4 Load/store single data item
return DisassembleThumb1LdSt(opA, MI, Opcode, insn, NumOps, NumOpsAdded,
B);
case 1:
// A6.2.4 Load/store single data item
return DisassembleThumb1LdStSP(MI, Opcode, insn, NumOps, NumOpsAdded, B);
case 2:
if (op3 <= 1) {
// A8.6.10 ADR
return DisassembleThumb1AddPCi(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
} else {
// A8.6.8 ADD (SP plus immediate)
return DisassembleThumb1AddSPi(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
default:
// A6.2.5 Miscellaneous 16-bit instructions
return DisassembleThumb1Misc(MI, Opcode, insn, NumOps, NumOpsAdded, B);
}
break;
case 3:
switch (op2) {
case 0:
if (op3 <= 1) {
// A8.6.189 STM / STMIA / STMEA
return DisassembleThumb1StMul(MI, Opcode, insn, NumOps, NumOpsAdded, B);
} else {
// A8.6.53 LDM / LDMIA / LDMFD
return DisassembleThumb1LdMul(MI, Opcode, insn, NumOps, NumOpsAdded, B);
}
case 1:
// A6.2.6 Conditional branch, and Supervisor Call
return DisassembleThumb1CondBr(MI, Opcode, insn, NumOps, NumOpsAdded, B);
case 2:
// Unconditional Branch, see B on page A8-44
return DisassembleThumb1Br(MI, Opcode, insn, NumOps, NumOpsAdded, B);
default:
assert(0 && "Unreachable code");
break;
}
break;
default:
assert(0 && "Unreachable code");
break;
}
return false;
}
///////////////////////////////////////////////
// //
// Thumb2 instruction disassembly functions. //
// //
///////////////////////////////////////////////
///////////////////////////////////////////////////////////
// //
// Note: the register naming follows the ARM convention! //
// //
///////////////////////////////////////////////////////////
static inline bool Thumb2SRSOpcode(unsigned Opcode) {
switch (Opcode) {
default:
return false;
case ARM::t2SRSDBW: case ARM::t2SRSDB:
case ARM::t2SRSIAW: case ARM::t2SRSIA:
return true;
}
}
static inline bool Thumb2RFEOpcode(unsigned Opcode) {
switch (Opcode) {
default:
return false;
case ARM::t2RFEDBW: case ARM::t2RFEDB:
case ARM::t2RFEIAW: case ARM::t2RFEIA:
return true;
}
}
// t2SRS[IA|DB]W/t2SRS[IA|DB]: mode_imm = Inst{4-0}
static bool DisassembleThumb2SRS(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded) {
MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0)));
NumOpsAdded = 1;
return true;
}
// t2RFE[IA|DB]W/t2RFE[IA|DB]: Rn
static bool DisassembleThumb2RFE(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
unsigned Rn = decodeRn(insn);
if (Rn == 15) {
DEBUG(errs() << "if n == 15 then UNPREDICTABLE\n");
return false;
}
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B,ARM::GPRRegClassID,Rn)));
NumOpsAdded = 1;
return true;
}
static bool DisassembleThumb2LdStMul(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
if (Thumb2SRSOpcode(Opcode))
return DisassembleThumb2SRS(MI, Opcode, insn, NumOps, NumOpsAdded);
if (Thumb2RFEOpcode(Opcode))
return DisassembleThumb2RFE(MI, Opcode, insn, NumOps, NumOpsAdded, B);
assert((Opcode == ARM::t2LDMIA || Opcode == ARM::t2LDMIA_UPD ||
Opcode == ARM::t2LDMDB || Opcode == ARM::t2LDMDB_UPD ||
Opcode == ARM::t2STMIA || Opcode == ARM::t2STMIA_UPD ||
Opcode == ARM::t2STMDB || Opcode == ARM::t2STMDB_UPD)
&& "Unexpected opcode");
assert(NumOps >= 4 && "Thumb2 LdStMul expects NumOps >= 4");
NumOpsAdded = 0;
unsigned Base = getRegisterEnum(B, ARM::GPRRegClassID, decodeRn(insn));
// Writeback to base.
if (Opcode == ARM::t2LDMIA_UPD || Opcode == ARM::t2LDMDB_UPD ||
Opcode == ARM::t2STMIA_UPD || Opcode == ARM::t2STMDB_UPD) {
MI.addOperand(MCOperand::CreateReg(Base));
++NumOpsAdded;
}
MI.addOperand(MCOperand::CreateReg(Base));
++NumOpsAdded;
// Handling the two predicate operands before the reglist.
if (B->DoPredicateOperands(MI, Opcode, insn, NumOps)) {
NumOpsAdded += 2;
} else {
DEBUG(errs() << "Expected predicate operands not found.\n");
return false;
}
unsigned RegListBits = insn & ((1 << 16) - 1);
// Fill the variadic part of reglist.
for (unsigned i = 0; i < 16; ++i)
if ((RegListBits >> i) & 1) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
i)));
++NumOpsAdded;
}
return true;
}
// t2LDREX: Rd Rn
// t2LDREXD: Rd Rs Rn
// t2LDREXB, t2LDREXH: Rd Rn
// t2STREX: Rs Rd Rn
// t2STREXD: Rm Rd Rs Rn
// t2STREXB, t2STREXH: Rm Rd Rn
static bool DisassembleThumb2LdStEx(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
assert(NumOps >= 2
&& OpInfo[0].RegClass > 0
&& OpInfo[1].RegClass > 0
&& "Expect >=2 operands and first two as reg operands");
bool isStore = (ARM::t2STREX <= Opcode && Opcode <= ARM::t2STREXH);
bool isSW = (Opcode == ARM::t2LDREX || Opcode == ARM::t2STREX);
bool isDW = (Opcode == ARM::t2LDREXD || Opcode == ARM::t2STREXD);
unsigned Rt = decodeRd(insn);
unsigned Rt2 = decodeRs(insn); // But note that this is Rd for t2STREX.
unsigned Rd = decodeRm(insn);
unsigned Rn = decodeRn(insn);
// Some sanity checking first.
if (isStore) {
// if d == n || d == t then UNPREDICTABLE
// if d == n || d == t || d == t2 then UNPREDICTABLE
if (isDW) {
if (Rd == Rn || Rd == Rt || Rd == Rt2) {
DEBUG(errs() << "if d == n || d == t || d == t2 then UNPREDICTABLE\n");
return false;
}
} else {
if (isSW) {
if (Rt2 == Rn || Rt2 == Rt) {
DEBUG(errs() << "if d == n || d == t then UNPREDICTABLE\n");
return false;
}
} else {
if (Rd == Rn || Rd == Rt) {
DEBUG(errs() << "if d == n || d == t then UNPREDICTABLE\n");
return false;
}
}
}
} else {
// Load
// A8.6.71 LDREXD
// if t == t2 then UNPREDICTABLE
if (isDW && Rt == Rt2) {
DEBUG(errs() << "if t == t2 then UNPREDICTABLE\n");
return false;
}
}
// Add the destination operand for store.
if (isStore) {
MI.addOperand(MCOperand::CreateReg(
getRegisterEnum(B, OpInfo[OpIdx].RegClass,
isSW ? Rt2 : Rd)));
++OpIdx;
}
// Source operand for store and destination operand for load.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[OpIdx].RegClass,
Rt)));
++OpIdx;
// Thumb2 doubleword complication: with an extra source/destination operand.
if (isDW) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B,OpInfo[OpIdx].RegClass,
Rt2)));
++OpIdx;
}
// Finally add the pointer operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[OpIdx].RegClass,
Rn)));
++OpIdx;
return true;
}
// t2LDRDi8: Rd Rs Rn imm8s4 (offset mode)
// t2LDRDpci: Rd Rs imm8s4 (Not decoded, prefer the generic t2LDRDi8 version)
// t2STRDi8: Rd Rs Rn imm8s4 (offset mode)
//
// Ditto for t2LDRD_PRE, t2LDRD_POST, t2STRD_PRE, t2STRD_POST, which are for
// disassembly only and do not have a tied_to writeback base register operand.
static bool DisassembleThumb2LdStDual(MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
if (!OpInfo) return false;
assert(NumOps >= 4
&& OpInfo[0].RegClass > 0
&& OpInfo[0].RegClass == OpInfo[1].RegClass
&& OpInfo[2].RegClass > 0
&& OpInfo[3].RegClass < 0
&& "Expect >= 4 operands and first 3 as reg operands");
// Thumnb allows for specifying Rt and Rt2, unlike ARM (which has Rt2==Rt+1).
unsigned Rt = decodeRd(insn);
unsigned Rt2 = decodeRs(insn);
unsigned Rn = decodeRn(insn);
// Some sanity checking first.
// A8.6.67 LDRD (literal) has its W bit as (0).
if (Opcode == ARM::t2LDRDi8 || Opcode == ARM::t2LDRD_PRE || Opcode == ARM::t2LDRD_POST) {
if (Rn == 15 && slice(insn, 21, 21) != 0)
return false;
} else {
// For Dual Store, PC cannot be used as the base register.
if (Rn == 15) {
DEBUG(errs() << "if n == 15 then UNPREDICTABLE\n");
return false;
}
}
if (Rt == Rt2) {
DEBUG(errs() << "if t == t2 then UNPREDICTABLE\n");
return false;
}
if (Opcode != ARM::t2LDRDi8 && Opcode != ARM::t2STRDi8) {
if (Rn == Rt || Rn == Rt2) {
DEBUG(errs() << "if wback && (n == t || n == t2) then UNPREDICTABLE\n");
return false;
}
}
// Add the <Rt> <Rt2> operands.
unsigned RegClassPair = OpInfo[0].RegClass;
unsigned RegClassBase = OpInfo[2].RegClass;
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, RegClassPair,
decodeRd(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, RegClassPair,
decodeRs(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, RegClassBase,
decodeRn(insn))));
// Finally add (+/-)imm8*4, depending on the U bit.
int Offset = getImm8(insn) * 4;
if (getUBit(insn) == 0)
Offset = -Offset;
MI.addOperand(MCOperand::CreateImm(Offset));
NumOpsAdded = 4;
return true;
}
// t2TBB, t2TBH: Rn Rm Pred-Imm Pred-CCR
static bool DisassembleThumb2TB(MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
assert(NumOps >= 2 && "Expect >= 2 operands");
// The generic version of TBB/TBH needs a base register.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRn(insn))));
// Add the index register.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRm(insn))));
NumOpsAdded = 2;
return true;
}
static inline bool Thumb2ShiftOpcode(unsigned Opcode) {
switch (Opcode) {
default:
return false;
case ARM::t2MOVCClsl: case ARM::t2MOVCClsr:
case ARM::t2MOVCCasr: case ARM::t2MOVCCror:
case ARM::t2LSLri: case ARM::t2LSRri:
case ARM::t2ASRri: case ARM::t2RORri:
return true;
}
}
// A6.3.11 Data-processing (shifted register)
//
// Two register operands (Rn=0b1111 no 1st operand reg): Rs Rm
// Two register operands (Rs=0b1111 no dst operand reg): Rn Rm
// Three register operands: Rs Rn Rm
// Three register operands: (Rn=0b1111 Conditional Move) Rs Ro(TIED_TO) Rm
//
// Constant shifts t2_so_reg is a 2-operand unit corresponding to the Thumb2
// register with shift forms: (Rm, ConstantShiftSpecifier).
// Constant shift specifier: Imm = (ShOp | ShAmt<<3).
//
// There are special instructions, like t2MOVsra_flag and t2MOVsrl_flag, which
// only require two register operands: Rd, Rm in ARM Reference Manual terms, and
// nothing else, because the shift amount is already specified.
// Similar case holds for t2MOVrx, t2ADDrr, ..., etc.
static bool DisassembleThumb2DPSoReg(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
// Special case handling.
if (Opcode == ARM::t2BR_JT) {
assert(NumOps == 4
&& OpInfo[0].RegClass == ARM::GPRRegClassID
&& OpInfo[1].RegClass == ARM::GPRRegClassID
&& OpInfo[2].RegClass < 0
&& OpInfo[3].RegClass < 0
&& "Exactly 4 operands expect and first two as reg operands");
// Only need to populate the src reg operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRm(insn))));
MI.addOperand(MCOperand::CreateReg(0));
MI.addOperand(MCOperand::CreateImm(0));
MI.addOperand(MCOperand::CreateImm(0));
NumOpsAdded = 4;
return true;
}
OpIdx = 0;
assert(NumOps >= 2
&& (OpInfo[0].RegClass == ARM::GPRRegClassID ||
OpInfo[0].RegClass == ARM::rGPRRegClassID)
&& (OpInfo[1].RegClass == ARM::GPRRegClassID ||
OpInfo[1].RegClass == ARM::rGPRRegClassID)
&& "Expect >= 2 operands and first two as reg operands");
bool ThreeReg = (NumOps > 2 && (OpInfo[2].RegClass == ARM::GPRRegClassID ||
OpInfo[2].RegClass == ARM::rGPRRegClassID));
bool NoDstReg = (decodeRs(insn) == 0xF);
// Build the register operands, followed by the constant shift specifier.
MI.addOperand(MCOperand::CreateReg(
getRegisterEnum(B, OpInfo[0].RegClass,
NoDstReg ? decodeRn(insn) : decodeRs(insn))));
++OpIdx;
if (ThreeReg) {
int Idx;
if ((Idx = MCID.getOperandConstraint(OpIdx, MCOI::TIED_TO)) != -1) {
// Process tied_to operand constraint.
MI.addOperand(MI.getOperand(Idx));
++OpIdx;
} else if (!NoDstReg) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[1].RegClass,
decodeRn(insn))));
++OpIdx;
} else {
DEBUG(errs() << "Thumb2 encoding error: d==15 for three-reg operands.\n");
return false;
}
}
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[OpIdx].RegClass,
decodeRm(insn))));
++OpIdx;
if (NumOps == OpIdx)
return true;
if (OpInfo[OpIdx].RegClass < 0 && !OpInfo[OpIdx].isPredicate()
&& !OpInfo[OpIdx].isOptionalDef()) {
if (Thumb2ShiftOpcode(Opcode)) {
unsigned Imm = getShiftAmtBits(insn);
ARM_AM::ShiftOpc ShOp = getShiftOpcForBits(slice(insn, 5, 4));
getImmShiftSE(ShOp, Imm);
MI.addOperand(MCOperand::CreateImm(Imm));
} else {
// Build the constant shift specifier operand.
unsigned bits2 = getShiftTypeBits(insn);
unsigned imm5 = getShiftAmtBits(insn);
ARM_AM::ShiftOpc ShOp = ARM_AM::no_shift;
unsigned ShAmt = decodeImmShift(bits2, imm5, ShOp);
MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(ShOp, ShAmt)));
}
++OpIdx;
}
return true;
}
// A6.3.1 Data-processing (modified immediate)
//
// Two register operands: Rs Rn ModImm
// One register operands (Rs=0b1111 no explicit dest reg): Rn ModImm
// One register operands (Rn=0b1111 no explicit src reg): Rs ModImm -
// {t2MOVi, t2MVNi}
//
// ModImm = ThumbExpandImm(i:imm3:imm8)
static bool DisassembleThumb2DPModImm(MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
unsigned RdRegClassID = OpInfo[0].RegClass;
assert(NumOps >= 2 && (RdRegClassID == ARM::GPRRegClassID ||
RdRegClassID == ARM::rGPRRegClassID)
&& "Expect >= 2 operands and first one as reg operand");
unsigned RnRegClassID = OpInfo[1].RegClass;
bool TwoReg = (RnRegClassID == ARM::GPRRegClassID
|| RnRegClassID == ARM::rGPRRegClassID);
bool NoDstReg = (decodeRs(insn) == 0xF);
// Build the register operands, followed by the modified immediate.
MI.addOperand(MCOperand::CreateReg(
getRegisterEnum(B, RdRegClassID,
NoDstReg ? decodeRn(insn) : decodeRs(insn))));
++OpIdx;
if (TwoReg) {
if (NoDstReg) {
DEBUG(errs()<<"Thumb2 encoding error: d==15 for DPModImm 2-reg instr.\n");
return false;
}
int Idx;
if ((Idx = MCID.getOperandConstraint(OpIdx, MCOI::TIED_TO)) != -1) {
// The reg operand is tied to the first reg operand.
MI.addOperand(MI.getOperand(Idx));
} else {
// Add second reg operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, RnRegClassID,
decodeRn(insn))));
}
++OpIdx;
}
// The modified immediate operand should come next.
assert(OpIdx < NumOps && OpInfo[OpIdx].RegClass < 0 &&
!OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()
&& "Pure imm operand expected");
// i:imm3:imm8
// A6.3.2 Modified immediate constants in Thumb instructions
unsigned imm12 = getIImm3Imm8(insn);
MI.addOperand(MCOperand::CreateImm(ThumbExpandImm(imm12)));
++OpIdx;
return true;
}
static inline bool Thumb2SaturateOpcode(unsigned Opcode) {
switch (Opcode) {
case ARM::t2SSAT: case ARM::t2SSAT16:
case ARM::t2USAT: case ARM::t2USAT16:
return true;
default:
return false;
}
}
/// DisassembleThumb2Sat - Disassemble Thumb2 saturate instructions:
/// o t2SSAT, t2USAT: Rs sat_pos Rn shamt
/// o t2SSAT16, t2USAT16: Rs sat_pos Rn
static bool DisassembleThumb2Sat(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned &NumOpsAdded, BO B) {
const MCInstrDesc &MCID = ARMInsts[Opcode];
NumOpsAdded = MCID.getNumOperands() - 2; // ignore predicate operands
// Disassemble the register def.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRs(insn))));
unsigned Pos = slice(insn, 4, 0);
if (Opcode == ARM::t2SSAT || Opcode == ARM::t2SSAT16)
Pos += 1;
MI.addOperand(MCOperand::CreateImm(Pos));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRn(insn))));
if (NumOpsAdded == 4) {
ARM_AM::ShiftOpc Opc = (slice(insn, 21, 21) != 0 ?
ARM_AM::asr : ARM_AM::lsl);
// Inst{14-12:7-6} encodes the imm5 shift amount.
unsigned ShAmt = slice(insn, 14, 12) << 2 | slice(insn, 7, 6);
if (ShAmt == 0) {
if (Opc == ARM_AM::asr)
ShAmt = 32;
else
Opc = ARM_AM::no_shift;
}
MI.addOperand(MCOperand::CreateImm(ARM_AM::getSORegOpc(Opc, ShAmt)));
}
return true;
}
// A6.3.3 Data-processing (plain binary immediate)
//
// o t2ADDri12, t2SUBri12: Rs Rn imm12
// o t2LEApcrel (ADR): Rs imm12
// o t2BFC (BFC): Rs Ro(TIED_TO) bf_inv_mask_imm
// o t2BFI (BFI): Rs Ro(TIED_TO) Rn bf_inv_mask_imm
// o t2MOVi16: Rs imm16
// o t2MOVTi16: Rs imm16
// o t2SBFX (SBFX): Rs Rn lsb width
// o t2UBFX (UBFX): Rs Rn lsb width
// o t2BFI (BFI): Rs Rn lsb width
static bool DisassembleThumb2DPBinImm(MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
unsigned RdRegClassID = OpInfo[0].RegClass;
assert(NumOps >= 2 && (RdRegClassID == ARM::GPRRegClassID ||
RdRegClassID == ARM::rGPRRegClassID)
&& "Expect >= 2 operands and first one as reg operand");
unsigned RnRegClassID = OpInfo[1].RegClass;
bool TwoReg = (RnRegClassID == ARM::GPRRegClassID
|| RnRegClassID == ARM::rGPRRegClassID);
// Build the register operand(s), followed by the immediate(s).
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, RdRegClassID,
decodeRs(insn))));
++OpIdx;
if (TwoReg) {
assert(NumOps >= 3 && "Expect >= 3 operands");
int Idx;
if ((Idx = MCID.getOperandConstraint(OpIdx, MCOI::TIED_TO)) != -1) {
// Process tied_to operand constraint.
MI.addOperand(MI.getOperand(Idx));
} else {
// Add src reg operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, RnRegClassID,
decodeRn(insn))));
}
++OpIdx;
}
if (Opcode == ARM::t2BFI) {
// Add val reg operand.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, RnRegClassID,
decodeRn(insn))));
++OpIdx;
}
assert(OpInfo[OpIdx].RegClass < 0 && !OpInfo[OpIdx].isPredicate()
&& !OpInfo[OpIdx].isOptionalDef()
&& "Pure imm operand expected");
// Pre-increment OpIdx.
++OpIdx;
if (Opcode == ARM::t2ADDri12 || Opcode == ARM::t2SUBri12
|| Opcode == ARM::t2LEApcrel)
MI.addOperand(MCOperand::CreateImm(getIImm3Imm8(insn)));
else if (Opcode == ARM::t2MOVi16 || Opcode == ARM::t2MOVTi16) {
if (!B->tryAddingSymbolicOperand(getImm16(insn), 4, MI))
MI.addOperand(MCOperand::CreateImm(getImm16(insn)));
} else if (Opcode == ARM::t2BFC || Opcode == ARM::t2BFI) {
uint32_t mask = 0;
if (getBitfieldInvMask(insn, mask))
MI.addOperand(MCOperand::CreateImm(mask));
else
return false;
} else {
// Handle the case of: lsb width
assert((Opcode == ARM::t2SBFX || Opcode == ARM::t2UBFX)
&& "Unexpected opcode");
MI.addOperand(MCOperand::CreateImm(getLsb(insn)));
MI.addOperand(MCOperand::CreateImm(getWidthMinus1(insn) + 1));
++OpIdx;
}
return true;
}
// A6.3.4 Table A6-15 Miscellaneous control instructions
// A8.6.41 DMB
// A8.6.42 DSB
// A8.6.49 ISB
static inline bool t2MiscCtrlInstr(uint32_t insn) {
if (slice(insn, 31, 20) == 0xf3b && slice(insn, 15, 14) == 2 &&
slice(insn, 12, 12) == 0)
return true;
return false;
}
// A6.3.4 Branches and miscellaneous control
//
// A8.6.16 B
// Branches: t2B, t2Bcc -> imm operand
//
// Branches: t2TPsoft -> no operand
//
// A8.6.23 BL, BLX (immediate)
// Branches (defined in ARMInstrThumb.td): tBL, tBLXi -> imm operand
//
// A8.6.26
// t2BXJ -> Rn
//
// Miscellaneous control:
// -> no operand (except pred-imm pred-ccr for CLREX, memory barrier variants)
//
// Hint: t2NOP, t2YIELD, t2WFE, t2WFI, t2SEV
// -> no operand (except pred-imm pred-ccr)
//
// t2DBG -> imm4 = Inst{3-0}
//
// t2MRS/t2MRSsys -> Rs
// t2MSR/t2MSRsys -> Rn mask=Inst{11-8}
// t2SMC -> imm4 = Inst{19-16}
static bool DisassembleThumb2BrMiscCtrl(MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
if (NumOps == 0)
return true;
if (Opcode == ARM::t2DMB || Opcode == ARM::t2DSB) {
// Inst{3-0} encodes the memory barrier option for the variants.
unsigned opt = slice(insn, 3, 0);
switch (opt) {
case ARM_MB::SY: case ARM_MB::ST:
case ARM_MB::ISH: case ARM_MB::ISHST:
case ARM_MB::NSH: case ARM_MB::NSHST:
case ARM_MB::OSH: case ARM_MB::OSHST:
MI.addOperand(MCOperand::CreateImm(opt));
NumOpsAdded = 1;
return true;
default:
return false;
}
}
if (t2MiscCtrlInstr(insn))
return true;
switch (Opcode) {
case ARM::t2CLREX:
case ARM::t2NOP:
case ARM::t2YIELD:
case ARM::t2WFE:
case ARM::t2WFI:
case ARM::t2SEV:
return true;
default:
break;
}
// FIXME: To enable correct asm parsing and disasm of CPS we need 3 different
// opcodes which match the same real instruction. This is needed since there's
// no current handling of optional arguments. Fix here when a better handling
// of optional arguments is implemented.
if (Opcode == ARM::t2CPS3p) {
MI.addOperand(MCOperand::CreateImm(slice(insn, 10, 9))); // imod
MI.addOperand(MCOperand::CreateImm(slice(insn, 7, 5))); // iflags
MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0))); // mode
NumOpsAdded = 3;
return true;
}
if (Opcode == ARM::t2CPS2p) {
MI.addOperand(MCOperand::CreateImm(slice(insn, 10, 9))); // imod
MI.addOperand(MCOperand::CreateImm(slice(insn, 7, 5))); // iflags
NumOpsAdded = 2;
return true;
}
if (Opcode == ARM::t2CPS1p) {
MI.addOperand(MCOperand::CreateImm(slice(insn, 4, 0))); // mode
NumOpsAdded = 1;
return true;
}
// DBG has its option specified in Inst{3-0}.
if (Opcode == ARM::t2DBG) {
MI.addOperand(MCOperand::CreateImm(slice(insn, 3, 0)));
NumOpsAdded = 1;
return true;
}
// MRS and MRSsys take one GPR reg Rs.
if (Opcode == ARM::t2MRS || Opcode == ARM::t2MRSsys) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRs(insn))));
NumOpsAdded = 1;
return true;
}
// BXJ takes one GPR reg Rn.
if (Opcode == ARM::t2BXJ) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRn(insn))));
NumOpsAdded = 1;
return true;
}
// MSR take a mask, followed by one GPR reg Rn. The mask contains the R Bit in
// bit 4, and the special register fields in bits 3-0.
if (Opcode == ARM::t2MSR) {
MI.addOperand(MCOperand::CreateImm(slice(insn, 20, 20) << 4 /* R Bit */ |
slice(insn, 11, 8) /* Special Reg */));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRn(insn))));
NumOpsAdded = 2;
return true;
}
// SMC take imm4.
if (Opcode == ARM::t2SMC) {
MI.addOperand(MCOperand::CreateImm(slice(insn, 19, 16)));
NumOpsAdded = 1;
return true;
}
// Some instructions have predicate operands first before the immediate.
if (Opcode == ARM::tBLXi || Opcode == ARM::tBL) {
// Handling the two predicate operands before the imm operand.
if (B->DoPredicateOperands(MI, Opcode, insn, NumOps))
NumOpsAdded += 2;
else {
DEBUG(errs() << "Expected predicate operands not found.\n");
return false;
}
}
// Add the imm operand.
int Offset = 0;
switch (Opcode) {
default:
assert(0 && "Unexpected opcode");
return false;
case ARM::t2B:
Offset = decodeImm32_B_EncodingT4(insn);
break;
case ARM::t2Bcc:
Offset = decodeImm32_B_EncodingT3(insn);
break;
case ARM::tBL:
Offset = decodeImm32_BL(insn);
break;
case ARM::tBLXi:
Offset = decodeImm32_BLX(insn);
break;
}
if (!B->tryAddingSymbolicOperand(Offset + B->getBuilderAddress() + 4, 4, MI))
MI.addOperand(MCOperand::CreateImm(Offset));
// This is an increment as some predicate operands may have been added first.
NumOpsAdded += 1;
return true;
}
static inline bool Thumb2PreloadOpcode(unsigned Opcode) {
switch (Opcode) {
default:
return false;
case ARM::t2PLDi12: case ARM::t2PLDi8:
case ARM::t2PLDs:
case ARM::t2PLDWi12: case ARM::t2PLDWi8:
case ARM::t2PLDWs:
case ARM::t2PLIi12: case ARM::t2PLIi8:
case ARM::t2PLIs:
return true;
}
}
static bool DisassembleThumb2PreLoad(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
// Preload Data/Instruction requires either 2 or 3 operands.
// t2PLDi12, t2PLDi8, t2PLDpci: Rn [+/-]imm12/imm8
// t2PLDr: Rn Rm
// t2PLDs: Rn Rm imm2=Inst{5-4}
// Same pattern applies for t2PLDW* and t2PLI*.
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
assert(NumOps >= 2 &&
OpInfo[0].RegClass == ARM::GPRRegClassID &&
"Expect >= 2 operands and first one as reg operand");
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRn(insn))));
++OpIdx;
if (OpInfo[OpIdx].RegClass == ARM::rGPRRegClassID) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::GPRRegClassID,
decodeRm(insn))));
} else {
assert(OpInfo[OpIdx].RegClass < 0 && !OpInfo[OpIdx].isPredicate()
&& !OpInfo[OpIdx].isOptionalDef()
&& "Pure imm operand expected");
int Offset = 0;
if (Opcode == ARM::t2PLDi8 || Opcode == ARM::t2PLDWi8 ||
Opcode == ARM::t2PLIi8) {
// A8.6.117 Encoding T2: add = FALSE
unsigned Imm8 = getImm8(insn);
Offset = -1 * Imm8;
} else {
// The i12 forms. See, for example, A8.6.117 Encoding T1.
// Note that currently t2PLDi12 also handles the previously named t2PLDpci
// opcode, that's why we use decodeImm12(insn) which returns +/- imm12.
Offset = decodeImm12(insn);
}
MI.addOperand(MCOperand::CreateImm(Offset));
}
++OpIdx;
if (OpIdx < NumOps && OpInfo[OpIdx].RegClass < 0 &&
!OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
// Fills in the shift amount for t2PLDs, t2PLDWs, t2PLIs.
MI.addOperand(MCOperand::CreateImm(slice(insn, 5, 4)));
++OpIdx;
}
return true;
}
static bool BadRegsThumb2LdSt(unsigned Opcode, uint32_t insn, bool Load,
unsigned R0, unsigned R1, unsigned R2, bool UseRm, bool WB) {
// Inst{22-21} encodes the data item transferred for load/store.
// For single word, it is encoded as ob10.
bool Word = (slice(insn, 22, 21) == 2);
bool Half = (slice(insn, 22, 21) == 1);
bool Byte = (slice(insn, 22, 21) == 0);
if (UseRm && BadReg(R2)) {
DEBUG(errs() << "if BadReg(m) then UNPREDICTABLE\n");
return true;
}
if (Load) {
if (!Word && R0 == 13) {
DEBUG(errs() << "if t == 13 then UNPREDICTABLE\n");
return true;
}
if (Byte) {
if (WB && R0 == 15 && slice(insn, 10, 8) == 3) {
// A8.6.78 LDRSB (immediate) Encoding T2 (errata markup 8.0)
DEBUG(errs() << "if t == 15 && PUW == '011' then UNPREDICTABLE\n");
return true;
}
}
// A6.3.8 Load halfword, memory hints
if (Half) {
if (WB) {
if (R0 == R1) {
// A8.6.82 LDRSH (immediate) Encoding T2
DEBUG(errs() << "if WB && n == t then UNPREDICTABLE\n");
return true;
}
if (R0 == 15 && slice(insn, 10, 8) == 3) {
// A8.6.82 LDRSH (immediate) Encoding T2 (errata markup 8.0)
DEBUG(errs() << "if t == 15 && PUW == '011' then UNPREDICTABLE\n");
return true;
}
} else {
if (Opcode == ARM::t2LDRHi8 || Opcode == ARM::t2LDRSHi8) {
if (R0 == 15 && slice(insn, 10, 8) == 4) {
// A8.6.82 LDRSH (immediate) Encoding T2
DEBUG(errs() << "if Rt == '1111' and PUW == '100' then SEE"
<< " \"Unallocated memory hints\"\n");
return true;
}
} else {
if (R0 == 15) {
// A8.6.82 LDRSH (immediate) Encoding T1
DEBUG(errs() << "if Rt == '1111' then SEE"
<< " \"Unallocated memory hints\"\n");
return true;
}
}
}
}
} else {
if (WB && R0 == R1) {
DEBUG(errs() << "if wback && n == t then UNPREDICTABLE\n");
return true;
}
if ((WB && R0 == 15) || (!WB && R1 == 15)) {
DEBUG(errs() << "if Rn == '1111' then UNDEFINED\n");
return true;
}
if (Word) {
if ((WB && R1 == 15) || (!WB && R0 == 15)) {
DEBUG(errs() << "if t == 15 then UNPREDICTABLE\n");
return true;
}
} else {
if ((WB && BadReg(R1)) || (!WB && BadReg(R0))) {
DEBUG(errs() << "if BadReg(t) then UNPREDICTABLE\n");
return true;
}
}
}
return false;
}
// A6.3.10 Store single data item
// A6.3.9 Load byte, memory hints
// A6.3.8 Load halfword, memory hints
// A6.3.7 Load word
//
// For example,
//
// t2LDRi12: Rd Rn (+)imm12
// t2LDRi8: Rd Rn (+/-)imm8 (+ if Inst{9} == 0b1)
// t2LDRs: Rd Rn Rm ConstantShiftSpecifier (see also
// DisassembleThumb2DPSoReg)
// t2LDR_POST: Rd Rn Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
// t2LDR_PRE: Rd Rn Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
//
// t2STRi12: Rd Rn (+)imm12
// t2STRi8: Rd Rn (+/-)imm8 (+ if Inst{9} == 0b1)
// t2STRs: Rd Rn Rm ConstantShiftSpecifier (see also
// DisassembleThumb2DPSoReg)
// t2STR_POST: Rn Rd Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
// t2STR_PRE: Rn Rd Rn(TIED_TO) (+/-)imm8 (+ if Inst{9} == 0b1)
//
// Note that for indexed modes, the Rn(TIED_TO) operand needs to be populated
// correctly, as LLVM AsmPrinter depends on it. For indexed stores, the first
// operand is Rn; for all the other instructions, Rd is the first operand.
//
// Delegates to DisassembleThumb2PreLoad() for preload data/instruction.
// Delegates to DisassembleThumb2Ldpci() for load * literal operations.
static bool DisassembleThumb2LdSt(bool Load, MCInst &MI, unsigned Opcode,
uint32_t insn, unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
unsigned Rn = decodeRn(insn);
if (Thumb2PreloadOpcode(Opcode))
return DisassembleThumb2PreLoad(MI, Opcode, insn, NumOps, NumOpsAdded, B);
// See, for example, A6.3.7 Load word: Table A6-18 Load word.
if (Load && Rn == 15)
return DisassembleThumb2Ldpci(MI, Opcode, insn, NumOps, NumOpsAdded, B);
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
assert(NumOps >= 3 &&
OpInfo[0].RegClass > 0 &&
OpInfo[1].RegClass > 0 &&
"Expect >= 3 operands and first two as reg operands");
bool ThreeReg = (OpInfo[2].RegClass > 0);
bool TIED_TO = ThreeReg && MCID.getOperandConstraint(2, MCOI::TIED_TO) != -1;
bool Imm12 = !ThreeReg && slice(insn, 23, 23) == 1; // ARMInstrThumb2.td
// Build the register operands, followed by the immediate.
unsigned R0 = 0, R1 = 0, R2 = 0;
unsigned Rd = decodeRd(insn);
int Imm = 0;
if (!Load && TIED_TO) {
R0 = Rn;
R1 = Rd;
} else {
R0 = Rd;
R1 = Rn;
}
if (ThreeReg) {
if (TIED_TO) {
R2 = Rn;
Imm = decodeImm8(insn);
} else {
R2 = decodeRm(insn);
// See, for example, A8.6.64 LDRB (register).
// And ARMAsmPrinter::printT2AddrModeSoRegOperand().
// LSL is the default shift opc, and LLVM does not expect it to be encoded
// as part of the immediate operand.
// Imm = ARM_AM::getSORegOpc(ARM_AM::lsl, slice(insn, 5, 4));
Imm = slice(insn, 5, 4);
}
} else {
if (Imm12)
Imm = getImm12(insn);
else
Imm = decodeImm8(insn);
}
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[OpIdx].RegClass,
R0)));
++OpIdx;
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[OpIdx].RegClass,
R1)));
++OpIdx;
if (ThreeReg) {
// This could be an offset register or a TIED_TO register.
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B,OpInfo[OpIdx].RegClass,
R2)));
++OpIdx;
}
if (BadRegsThumb2LdSt(Opcode, insn, Load, R0, R1, R2, ThreeReg & !TIED_TO,
TIED_TO))
return false;
assert(OpInfo[OpIdx].RegClass < 0 && !OpInfo[OpIdx].isPredicate()
&& !OpInfo[OpIdx].isOptionalDef()
&& "Pure imm operand expected");
MI.addOperand(MCOperand::CreateImm(Imm));
++OpIdx;
return true;
}
// A6.3.12 Data-processing (register)
//
// Two register operands [rotate]: Rs Rm [rotation(= (rotate:'000'))]
// Three register operands only: Rs Rn Rm
// Three register operands [rotate]: Rs Rn Rm [rotation(= (rotate:'000'))]
//
// Parallel addition and subtraction 32-bit Thumb instructions: Rs Rn Rm
//
// Miscellaneous operations: Rs [Rn] Rm
static bool DisassembleThumb2DPReg(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCInstrDesc &MCID = ARMInsts[Opcode];
const MCOperandInfo *OpInfo = MCID.OpInfo;
unsigned &OpIdx = NumOpsAdded;
OpIdx = 0;
assert(NumOps >= 2 &&
OpInfo[0].RegClass > 0 &&
OpInfo[1].RegClass > 0 &&
"Expect >= 2 operands and first two as reg operands");
// Build the register operands, followed by the optional rotation amount.
bool ThreeReg = NumOps > 2 && OpInfo[2].RegClass > 0;
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[OpIdx].RegClass,
decodeRs(insn))));
++OpIdx;
if (ThreeReg) {
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B,OpInfo[OpIdx].RegClass,
decodeRn(insn))));
++OpIdx;
}
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, OpInfo[OpIdx].RegClass,
decodeRm(insn))));
++OpIdx;
if (OpIdx < NumOps && OpInfo[OpIdx].RegClass < 0
&& !OpInfo[OpIdx].isPredicate() && !OpInfo[OpIdx].isOptionalDef()) {
// Add the rotation amount immediate.
MI.addOperand(MCOperand::CreateImm(decodeRotate(insn)));
++OpIdx;
}
return true;
}
// A6.3.16 Multiply, multiply accumulate, and absolute difference
//
// t2MLA, t2MLS, t2SMMLA, t2SMMLS: Rs Rn Rm Ra=Inst{15-12}
// t2MUL, t2SMMUL: Rs Rn Rm
// t2SMLA[BB|BT|TB|TT|WB|WT]: Rs Rn Rm Ra=Inst{15-12}
// t2SMUL[BB|BT|TB|TT|WB|WT]: Rs Rn Rm
//
// Dual halfword multiply: t2SMUAD[X], t2SMUSD[X], t2SMLAD[X], t2SMLSD[X]:
// Rs Rn Rm Ra=Inst{15-12}
//
// Unsigned Sum of Absolute Differences [and Accumulate]
// Rs Rn Rm [Ra=Inst{15-12}]
static bool DisassembleThumb2Mul(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
assert(NumOps >= 3 &&
OpInfo[0].RegClass == ARM::rGPRRegClassID &&
OpInfo[1].RegClass == ARM::rGPRRegClassID &&
OpInfo[2].RegClass == ARM::rGPRRegClassID &&
"Expect >= 3 operands and first three as reg operands");
// Build the register operands.
bool FourReg = NumOps > 3 && OpInfo[3].RegClass == ARM::rGPRRegClassID;
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRs(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRn(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRm(insn))));
if (FourReg)
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRd(insn))));
NumOpsAdded = FourReg ? 4 : 3;
return true;
}
// A6.3.17 Long multiply, long multiply accumulate, and divide
//
// t2SMULL, t2UMULL, t2SMLAL, t2UMLAL, t2UMAAL: RdLo RdHi Rn Rm
// where RdLo = Inst{15-12} and RdHi = Inst{11-8}
//
// Halfword multiple accumulate long: t2SMLAL<x><y>: RdLo RdHi Rn Rm
// where RdLo = Inst{15-12} and RdHi = Inst{11-8}
//
// Dual halfword multiple: t2SMLALD[X], t2SMLSLD[X]: RdLo RdHi Rn Rm
// where RdLo = Inst{15-12} and RdHi = Inst{11-8}
//
// Signed/Unsigned divide: t2SDIV, t2UDIV: Rs Rn Rm
static bool DisassembleThumb2LongMul(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO B) {
const MCOperandInfo *OpInfo = ARMInsts[Opcode].OpInfo;
assert(NumOps >= 3 &&
OpInfo[0].RegClass == ARM::rGPRRegClassID &&
OpInfo[1].RegClass == ARM::rGPRRegClassID &&
OpInfo[2].RegClass == ARM::rGPRRegClassID &&
"Expect >= 3 operands and first three as reg operands");
bool FourReg = NumOps > 3 && OpInfo[3].RegClass == ARM::rGPRRegClassID;
// Build the register operands.
if (FourReg)
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRd(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRs(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRn(insn))));
MI.addOperand(MCOperand::CreateReg(getRegisterEnum(B, ARM::rGPRRegClassID,
decodeRm(insn))));
if (FourReg)
NumOpsAdded = 4;
else
NumOpsAdded = 3;
return true;
}
// See A6.3 32-bit Thumb instruction encoding for instruction classes
// corresponding to (op1, op2, op).
//
// Table A6-9 32-bit Thumb instruction encoding
// op1 op2 op Instruction class, see
// --- ------- -- -----------------------------------------------------------
// 01 00xx0xx - Load/store multiple on page A6-23
// 00xx1xx - Load/store dual, load/store exclusive, table branch on
// page A6-24
// 01xxxxx - Data-processing (shifted register) on page A6-31
// 1xxxxxx - Coprocessor instructions on page A6-40
// 10 x0xxxxx 0 Data-processing (modified immediate) on page A6-15
// x1xxxxx 0 Data-processing (plain binary immediate) on page A6-19
// - 1 Branches and miscellaneous control on page A6-20
// 11 000xxx0 - Store single data item on page A6-30
// 001xxx0 - Advanced SIMD element or structure load/store instructions
// on page A7-27
// 00xx001 - Load byte, memory hints on page A6-28
// 00xx011 - Load halfword, memory hints on page A6-26
// 00xx101 - Load word on page A6-25
// 00xx111 - UNDEFINED
// 010xxxx - Data-processing (register) on page A6-33
// 0110xxx - Multiply, multiply accumulate, and absolute difference on
// page A6-38
// 0111xxx - Long multiply, long multiply accumulate, and divide on
// page A6-39
// 1xxxxxx - Coprocessor instructions on page A6-40
//
static bool DisassembleThumb2(uint16_t op1, uint16_t op2, uint16_t op,
MCInst &MI, unsigned Opcode, uint32_t insn, unsigned short NumOps,
unsigned &NumOpsAdded, BO B) {
switch (op1) {
case 1:
if (slice(op2, 6, 5) == 0) {
if (slice(op2, 2, 2) == 0) {
// Load/store multiple.
return DisassembleThumb2LdStMul(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
// Load/store dual, load/store exclusive, table branch, otherwise.
assert(slice(op2, 2, 2) == 1 && "Thumb2 encoding error!");
if ((ARM::t2LDREX <= Opcode && Opcode <= ARM::t2LDREXH) ||
(ARM::t2STREX <= Opcode && Opcode <= ARM::t2STREXH)) {
// Load/store exclusive.
return DisassembleThumb2LdStEx(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
if (Opcode == ARM::t2LDRDi8 ||
Opcode == ARM::t2LDRD_PRE || Opcode == ARM::t2LDRD_POST ||
Opcode == ARM::t2STRDi8 ||
Opcode == ARM::t2STRD_PRE || Opcode == ARM::t2STRD_POST) {
// Load/store dual.
return DisassembleThumb2LdStDual(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
if (Opcode == ARM::t2TBB || Opcode == ARM::t2TBH) {
// Table branch.
return DisassembleThumb2TB(MI, Opcode, insn, NumOps, NumOpsAdded, B);
}
} else if (slice(op2, 6, 5) == 1) {
// Data-processing (shifted register).
return DisassembleThumb2DPSoReg(MI, Opcode, insn, NumOps, NumOpsAdded, B);
}
// FIXME: A6.3.18 Coprocessor instructions
// But see ThumbDisassembler::getInstruction().
break;
case 2:
if (op == 0) {
if (slice(op2, 5, 5) == 0)
// Data-processing (modified immediate)
return DisassembleThumb2DPModImm(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
if (Thumb2SaturateOpcode(Opcode))
return DisassembleThumb2Sat(MI, Opcode, insn, NumOpsAdded, B);
// Data-processing (plain binary immediate)
return DisassembleThumb2DPBinImm(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
// Branches and miscellaneous control on page A6-20.
return DisassembleThumb2BrMiscCtrl(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
case 3:
switch (slice(op2, 6, 5)) {
case 0:
// Load/store instructions...
if (slice(op2, 0, 0) == 0) {
if (slice(op2, 4, 4) == 0) {
// Store single data item on page A6-30
return DisassembleThumb2LdSt(false, MI,Opcode,insn,NumOps,NumOpsAdded,
B);
} else {
// FIXME: Advanced SIMD element or structure load/store instructions.
// But see ThumbDisassembler::getInstruction().
;
}
} else {
// Table A6-9 32-bit Thumb instruction encoding: Load byte|halfword|word
return DisassembleThumb2LdSt(true, MI, Opcode, insn, NumOps,
NumOpsAdded, B);
}
break;
case 1:
if (slice(op2, 4, 4) == 0) {
// A6.3.12 Data-processing (register)
return DisassembleThumb2DPReg(MI, Opcode, insn, NumOps, NumOpsAdded, B);
} else if (slice(op2, 3, 3) == 0) {
// A6.3.16 Multiply, multiply accumulate, and absolute difference
return DisassembleThumb2Mul(MI, Opcode, insn, NumOps, NumOpsAdded, B);
} else {
// A6.3.17 Long multiply, long multiply accumulate, and divide
return DisassembleThumb2LongMul(MI, Opcode, insn, NumOps, NumOpsAdded,
B);
}
break;
default:
// FIXME: A6.3.18 Coprocessor instructions
// But see ThumbDisassembler::getInstruction().
;
break;
}
break;
default:
assert(0 && "Thumb2 encoding error!");
break;
}
return false;
}
static bool DisassembleThumbFrm(MCInst &MI, unsigned Opcode, uint32_t insn,
unsigned short NumOps, unsigned &NumOpsAdded, BO Builder) {
uint16_t HalfWord = slice(insn, 31, 16);
if (HalfWord == 0) {
// A6.2 16-bit Thumb instruction encoding
// op = bits[15:10]
uint16_t op = slice(insn, 15, 10);
return DisassembleThumb1(op, MI, Opcode, insn, NumOps, NumOpsAdded,
Builder);
}
unsigned bits15_11 = slice(HalfWord, 15, 11);
// A6.1 Thumb instruction set encoding
if (!(bits15_11 == 0x1D || bits15_11 == 0x1E || bits15_11 == 0x1F)) {
assert("Bits[15:11] first halfword of Thumb2 instruction is out of range");
return false;
}
// A6.3 32-bit Thumb instruction encoding
uint16_t op1 = slice(HalfWord, 12, 11);
uint16_t op2 = slice(HalfWord, 10, 4);
uint16_t op = slice(insn, 15, 15);
return DisassembleThumb2(op1, op2, op, MI, Opcode, insn, NumOps, NumOpsAdded,
Builder);
}