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// Copyright 2013 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#if V8_TARGET_ARCH_ARM64
#include "src/arm64/assembler-arm64-inl.h"
#include "src/arm64/instructions-arm64.h"
namespace v8 {
namespace internal {
bool Instruction::IsLoad() const {
if (Mask(LoadStoreAnyFMask) != LoadStoreAnyFixed) {
return false;
}
if (Mask(LoadStorePairAnyFMask) == LoadStorePairAnyFixed) {
return Mask(LoadStorePairLBit) != 0;
} else {
LoadStoreOp op = static_cast<LoadStoreOp>(Mask(LoadStoreMask));
switch (op) {
case LDRB_w:
case LDRH_w:
case LDR_w:
case LDR_x:
case LDRSB_w:
case LDRSB_x:
case LDRSH_w:
case LDRSH_x:
case LDRSW_x:
case LDR_b:
case LDR_h:
case LDR_s:
case LDR_d:
case LDR_q:
return true;
default: return false;
}
}
}
bool Instruction::IsStore() const {
if (Mask(LoadStoreAnyFMask) != LoadStoreAnyFixed) {
return false;
}
if (Mask(LoadStorePairAnyFMask) == LoadStorePairAnyFixed) {
return Mask(LoadStorePairLBit) == 0;
} else {
LoadStoreOp op = static_cast<LoadStoreOp>(Mask(LoadStoreMask));
switch (op) {
case STRB_w:
case STRH_w:
case STR_w:
case STR_x:
case STR_b:
case STR_h:
case STR_s:
case STR_d:
case STR_q:
return true;
default: return false;
}
}
}
static uint64_t RotateRight(uint64_t value,
unsigned int rotate,
unsigned int width) {
DCHECK_LE(width, 64);
rotate &= 63;
return ((value & ((1ULL << rotate) - 1ULL)) << (width - rotate)) |
(value >> rotate);
}
static uint64_t RepeatBitsAcrossReg(unsigned reg_size,
uint64_t value,
unsigned width) {
DCHECK((width == 2) || (width == 4) || (width == 8) || (width == 16) ||
(width == 32));
DCHECK((reg_size == kWRegSizeInBits) || (reg_size == kXRegSizeInBits));
uint64_t result = value & ((1ULL << width) - 1ULL);
for (unsigned i = width; i < reg_size; i *= 2) {
result |= (result << i);
}
return result;
}
// Logical immediates can't encode zero, so a return value of zero is used to
// indicate a failure case. Specifically, where the constraints on imm_s are not
// met.
uint64_t Instruction::ImmLogical() {
unsigned reg_size = SixtyFourBits() ? kXRegSizeInBits : kWRegSizeInBits;
int32_t n = BitN();
int32_t imm_s = ImmSetBits();
int32_t imm_r = ImmRotate();
// An integer is constructed from the n, imm_s and imm_r bits according to
// the following table:
//
// N imms immr size S R
// 1 ssssss rrrrrr 64 UInt(ssssss) UInt(rrrrrr)
// 0 0sssss xrrrrr 32 UInt(sssss) UInt(rrrrr)
// 0 10ssss xxrrrr 16 UInt(ssss) UInt(rrrr)
// 0 110sss xxxrrr 8 UInt(sss) UInt(rrr)
// 0 1110ss xxxxrr 4 UInt(ss) UInt(rr)
// 0 11110s xxxxxr 2 UInt(s) UInt(r)
// (s bits must not be all set)
//
// A pattern is constructed of size bits, where the least significant S+1
// bits are set. The pattern is rotated right by R, and repeated across a
// 32 or 64-bit value, depending on destination register width.
//
if (n == 1) {
if (imm_s == 0x3F) {
return 0;
}
uint64_t bits = (1ULL << (imm_s + 1)) - 1;
return RotateRight(bits, imm_r, 64);
} else {
if ((imm_s >> 1) == 0x1F) {
return 0;
}
for (int width = 0x20; width >= 0x2; width >>= 1) {
if ((imm_s & width) == 0) {
int mask = width - 1;
if ((imm_s & mask) == mask) {
return 0;
}
uint64_t bits = (1ULL << ((imm_s & mask) + 1)) - 1;
return RepeatBitsAcrossReg(reg_size,
RotateRight(bits, imm_r & mask, width),
width);
}
}
}
UNREACHABLE();
}
uint32_t Instruction::ImmNEONabcdefgh() const {
return ImmNEONabc() << 5 | ImmNEONdefgh();
}
float Instruction::ImmFP32() { return Imm8ToFP32(ImmFP()); }
double Instruction::ImmFP64() { return Imm8ToFP64(ImmFP()); }
float Instruction::ImmNEONFP32() const { return Imm8ToFP32(ImmNEONabcdefgh()); }
double Instruction::ImmNEONFP64() const {
return Imm8ToFP64(ImmNEONabcdefgh());
}
unsigned CalcLSDataSize(LoadStoreOp op) {
DCHECK_EQ(static_cast<unsigned>(LSSize_offset + LSSize_width),
kInstrSize * 8);
unsigned size = static_cast<Instr>(op) >> LSSize_offset;
if ((op & LSVector_mask) != 0) {
// Vector register memory operations encode the access size in the "size"
// and "opc" fields.
if ((size == 0) && ((op & LSOpc_mask) >> LSOpc_offset) >= 2) {
size = kQRegSizeLog2;
}
}
return size;
}
unsigned CalcLSPairDataSize(LoadStorePairOp op) {
static_assert(kXRegSize == kDRegSize, "X and D registers must be same size.");
static_assert(kWRegSize == kSRegSize, "W and S registers must be same size.");
switch (op) {
case STP_q:
case LDP_q:
return kQRegSizeLog2;
case STP_x:
case LDP_x:
case STP_d:
case LDP_d:
return kXRegSizeLog2;
default:
return kWRegSizeLog2;
}
}
int64_t Instruction::ImmPCOffset() {
int64_t offset;
if (IsPCRelAddressing()) {
// PC-relative addressing. Only ADR is supported.
offset = ImmPCRel();
} else if (BranchType() != UnknownBranchType) {
// All PC-relative branches.
// Relative branch offsets are instruction-size-aligned.
offset = ImmBranch() << kInstrSizeLog2;
} else if (IsUnresolvedInternalReference()) {
// Internal references are always word-aligned.
offset = ImmUnresolvedInternalReference() << kInstrSizeLog2;
} else {
// Load literal (offset from PC).
DCHECK(IsLdrLiteral());
// The offset is always shifted by 2 bits, even for loads to 64-bits
// registers.
offset = ImmLLiteral() << kInstrSizeLog2;
}
return offset;
}
Instruction* Instruction::ImmPCOffsetTarget() {
return InstructionAtOffset(ImmPCOffset());
}
bool Instruction::IsValidImmPCOffset(ImmBranchType branch_type,
ptrdiff_t offset) {
return is_intn(offset, ImmBranchRangeBitwidth(branch_type));
}
bool Instruction::IsTargetInImmPCOffsetRange(Instruction* target) {
return IsValidImmPCOffset(BranchType(), DistanceTo(target));
}
void Instruction::SetImmPCOffsetTarget(const AssemblerOptions& options,
Instruction* target) {
if (IsPCRelAddressing()) {
SetPCRelImmTarget(options, target);
} else if (BranchType() != UnknownBranchType) {
SetBranchImmTarget(target);
} else if (IsUnresolvedInternalReference()) {
SetUnresolvedInternalReferenceImmTarget(options, target);
} else {
// Load literal (offset from PC).
SetImmLLiteral(target);
}
}
void Instruction::SetPCRelImmTarget(const AssemblerOptions& options,
Instruction* target) {
// ADRP is not supported, so 'this' must point to an ADR instruction.
DCHECK(IsAdr());
ptrdiff_t target_offset = DistanceTo(target);
Instr imm;
if (Instruction::IsValidPCRelOffset(target_offset)) {
imm = Assembler::ImmPCRelAddress(static_cast<int>(target_offset));
SetInstructionBits(Mask(~ImmPCRel_mask) | imm);
} else {
PatchingAssembler patcher(options, reinterpret_cast<byte*>(this),
PatchingAssembler::kAdrFarPatchableNInstrs);
patcher.PatchAdrFar(target_offset);
}
}
void Instruction::SetBranchImmTarget(Instruction* target) {
DCHECK(IsAligned(DistanceTo(target), kInstrSize));
DCHECK(
IsValidImmPCOffset(BranchType(), DistanceTo(target) >> kInstrSizeLog2));
int offset = static_cast<int>(DistanceTo(target) >> kInstrSizeLog2);
Instr branch_imm = 0;
uint32_t imm_mask = 0;
switch (BranchType()) {
case CondBranchType: {
branch_imm = Assembler::ImmCondBranch(offset);
imm_mask = ImmCondBranch_mask;
break;
}
case UncondBranchType: {
branch_imm = Assembler::ImmUncondBranch(offset);
imm_mask = ImmUncondBranch_mask;
break;
}
case CompareBranchType: {
branch_imm = Assembler::ImmCmpBranch(offset);
imm_mask = ImmCmpBranch_mask;
break;
}
case TestBranchType: {
branch_imm = Assembler::ImmTestBranch(offset);
imm_mask = ImmTestBranch_mask;
break;
}
default: UNREACHABLE();
}
SetInstructionBits(Mask(~imm_mask) | branch_imm);
}
void Instruction::SetUnresolvedInternalReferenceImmTarget(
const AssemblerOptions& options, Instruction* target) {
DCHECK(IsUnresolvedInternalReference());
DCHECK(IsAligned(DistanceTo(target), kInstrSize));
DCHECK(is_int32(DistanceTo(target) >> kInstrSizeLog2));
int32_t target_offset =
static_cast<int32_t>(DistanceTo(target) >> kInstrSizeLog2);
uint32_t high16 = unsigned_bitextract_32(31, 16, target_offset);
uint32_t low16 = unsigned_bitextract_32(15, 0, target_offset);
PatchingAssembler patcher(options, reinterpret_cast<byte*>(this), 2);
patcher.brk(high16);
patcher.brk(low16);
}
void Instruction::SetImmLLiteral(Instruction* source) {
DCHECK(IsLdrLiteral());
DCHECK(IsAligned(DistanceTo(source), kInstrSize));
DCHECK(Assembler::IsImmLLiteral(DistanceTo(source)));
Instr imm = Assembler::ImmLLiteral(
static_cast<int>(DistanceTo(source) >> kLoadLiteralScaleLog2));
Instr mask = ImmLLiteral_mask;
SetInstructionBits(Mask(~mask) | imm);
}
// TODO(jbramley): We can't put this inline in the class because things like
// xzr and Register are not defined in that header. Consider adding
// instructions-arm64-inl.h to work around this.
bool InstructionSequence::IsInlineData() const {
// Inline data is encoded as a single movz instruction which writes to xzr
// (x31).
return IsMovz() && SixtyFourBits() && (Rd() == kZeroRegCode);
// TODO(all): If we extend ::InlineData() to support bigger data, we need
// to update this method too.
}
// TODO(jbramley): We can't put this inline in the class because things like
// xzr and Register are not defined in that header. Consider adding
// instructions-arm64-inl.h to work around this.
uint64_t InstructionSequence::InlineData() const {
DCHECK(IsInlineData());
uint64_t payload = ImmMoveWide();
// TODO(all): If we extend ::InlineData() to support bigger data, we need
// to update this method too.
return payload;
}
NEONFormatDecoder::NEONFormatDecoder(const Instruction* instr) {
instrbits_ = instr->InstructionBits();
SetFormatMaps(IntegerFormatMap());
}
NEONFormatDecoder::NEONFormatDecoder(const Instruction* instr,
const NEONFormatMap* format) {
instrbits_ = instr->InstructionBits();
SetFormatMaps(format);
}
NEONFormatDecoder::NEONFormatDecoder(const Instruction* instr,
const NEONFormatMap* format0,
const NEONFormatMap* format1) {
instrbits_ = instr->InstructionBits();
SetFormatMaps(format0, format1);
}
NEONFormatDecoder::NEONFormatDecoder(const Instruction* instr,
const NEONFormatMap* format0,
const NEONFormatMap* format1,
const NEONFormatMap* format2) {
instrbits_ = instr->InstructionBits();
SetFormatMaps(format0, format1, format2);
}
void NEONFormatDecoder::SetFormatMaps(const NEONFormatMap* format0,
const NEONFormatMap* format1,
const NEONFormatMap* format2) {
DCHECK_NOT_NULL(format0);
formats_[0] = format0;
formats_[1] = (format1 == nullptr) ? formats_[0] : format1;
formats_[2] = (format2 == nullptr) ? formats_[1] : format2;
}
void NEONFormatDecoder::SetFormatMap(unsigned index,
const NEONFormatMap* format) {
DCHECK_LT(index, arraysize(formats_));
DCHECK_NOT_NULL(format);
formats_[index] = format;
}
const char* NEONFormatDecoder::SubstitutePlaceholders(const char* string) {
return Substitute(string, kPlaceholder, kPlaceholder, kPlaceholder);
}
const char* NEONFormatDecoder::Substitute(const char* string,
SubstitutionMode mode0,
SubstitutionMode mode1,
SubstitutionMode mode2) {
snprintf(form_buffer_, sizeof(form_buffer_), string, GetSubstitute(0, mode0),
GetSubstitute(1, mode1), GetSubstitute(2, mode2));
return form_buffer_;
}
const char* NEONFormatDecoder::Mnemonic(const char* mnemonic) {
if ((instrbits_ & NEON_Q) != 0) {
snprintf(mne_buffer_, sizeof(mne_buffer_), "%s2", mnemonic);
return mne_buffer_;
}
return mnemonic;
}
VectorFormat NEONFormatDecoder::GetVectorFormat(int format_index) {
return GetVectorFormat(formats_[format_index]);
}
VectorFormat NEONFormatDecoder::GetVectorFormat(
const NEONFormatMap* format_map) {
static const VectorFormat vform[] = {
kFormatUndefined, kFormat8B, kFormat16B, kFormat4H, kFormat8H,
kFormat2S, kFormat4S, kFormat1D, kFormat2D, kFormatB,
kFormatH, kFormatS, kFormatD};
DCHECK_LT(GetNEONFormat(format_map), arraysize(vform));
return vform[GetNEONFormat(format_map)];
}
const char* NEONFormatDecoder::GetSubstitute(int index, SubstitutionMode mode) {
if (mode == kFormat) {
return NEONFormatAsString(GetNEONFormat(formats_[index]));
}
DCHECK_EQ(mode, kPlaceholder);
return NEONFormatAsPlaceholder(GetNEONFormat(formats_[index]));
}
NEONFormat NEONFormatDecoder::GetNEONFormat(const NEONFormatMap* format_map) {
return format_map->map[PickBits(format_map->bits)];
}
const char* NEONFormatDecoder::NEONFormatAsString(NEONFormat format) {
static const char* formats[] = {"undefined", "8b", "16b", "4h", "8h",
"2s", "4s", "1d", "2d", "b",
"h", "s", "d"};
DCHECK_LT(format, arraysize(formats));
return formats[format];
}
const char* NEONFormatDecoder::NEONFormatAsPlaceholder(NEONFormat format) {
DCHECK((format == NF_B) || (format == NF_H) || (format == NF_S) ||
(format == NF_D) || (format == NF_UNDEF));
static const char* formats[] = {
"undefined", "undefined", "undefined", "undefined", "undefined",
"undefined", "undefined", "undefined", "undefined", "'B",
"'H", "'S", "'D"};
return formats[format];
}
uint8_t NEONFormatDecoder::PickBits(const uint8_t bits[]) {
uint8_t result = 0;
for (unsigned b = 0; b < kNEONFormatMaxBits; b++) {
if (bits[b] == 0) break;
result <<= 1;
result |= ((instrbits_ & (1 << bits[b])) == 0) ? 0 : 1;
}
return result;
}
} // namespace internal
} // namespace v8
#endif // V8_TARGET_ARCH_ARM64