deps/v8/src/arm64/instructions-arm64.cc
// 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.
#include "src/v8.h"
#if V8_TARGET_ARCH_ARM64
#define ARM64_DEFINE_FP_STATICS
#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(LoadStoreOpMask));
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_s:
case LDR_d: 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(LoadStoreOpMask));
switch (op) {
case STRB_w:
case STRH_w:
case STR_w:
case STR_x:
case STR_s:
case STR_d: return true;
default: return false;
}
}
}
static uint64_t RotateRight(uint64_t value,
unsigned int rotate,
unsigned int width) {
DCHECK(width <= 64);
rotate &= 63;
return ((value & ((1UL << rotate) - 1UL)) << (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 & ((1UL << width) - 1UL);
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;
int64_t n = BitN();
int64_t imm_s = ImmSetBits();
int64_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 = (1UL << (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 = (1UL << ((imm_s & mask) + 1)) - 1;
return RepeatBitsAcrossReg(reg_size,
RotateRight(bits, imm_r & mask, width),
width);
}
}
}
UNREACHABLE();
return 0;
}
float Instruction::ImmFP32() {
// ImmFP: abcdefgh (8 bits)
// Single: aBbb.bbbc.defg.h000.0000.0000.0000.0000 (32 bits)
// where B is b ^ 1
uint32_t bits = ImmFP();
uint32_t bit7 = (bits >> 7) & 0x1;
uint32_t bit6 = (bits >> 6) & 0x1;
uint32_t bit5_to_0 = bits & 0x3f;
uint32_t result = (bit7 << 31) | ((32 - bit6) << 25) | (bit5_to_0 << 19);
return rawbits_to_float(result);
}
double Instruction::ImmFP64() {
// ImmFP: abcdefgh (8 bits)
// Double: aBbb.bbbb.bbcd.efgh.0000.0000.0000.0000
// 0000.0000.0000.0000.0000.0000.0000.0000 (64 bits)
// where B is b ^ 1
uint32_t bits = ImmFP();
uint64_t bit7 = (bits >> 7) & 0x1;
uint64_t bit6 = (bits >> 6) & 0x1;
uint64_t bit5_to_0 = bits & 0x3f;
uint64_t result = (bit7 << 63) | ((256 - bit6) << 54) | (bit5_to_0 << 48);
return rawbits_to_double(result);
}
LSDataSize CalcLSPairDataSize(LoadStorePairOp op) {
switch (op) {
case STP_x:
case LDP_x:
case STP_d:
case LDP_d: return LSDoubleWord;
default: return LSWord;
}
}
ptrdiff_t Instruction::ImmPCOffset() {
ptrdiff_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() << kInstructionSizeLog2;
} 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() << kInstructionSizeLog2;
}
return offset;
}
Instruction* Instruction::ImmPCOffsetTarget() {
return InstructionAtOffset(ImmPCOffset());
}
bool Instruction::IsValidImmPCOffset(ImmBranchType branch_type,
int32_t offset) {
return is_intn(offset, ImmBranchRangeBitwidth(branch_type));
}
bool Instruction::IsTargetInImmPCOffsetRange(Instruction* target) {
return IsValidImmPCOffset(BranchType(), DistanceTo(target));
}
void Instruction::SetImmPCOffsetTarget(Instruction* target) {
if (IsPCRelAddressing()) {
SetPCRelImmTarget(target);
} else if (BranchType() != UnknownBranchType) {
SetBranchImmTarget(target);
} else {
SetImmLLiteral(target);
}
}
void Instruction::SetPCRelImmTarget(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(target_offset);
SetInstructionBits(Mask(~ImmPCRel_mask) | imm);
} else {
PatchingAssembler patcher(this,
PatchingAssembler::kAdrFarPatchableNInstrs);
patcher.PatchAdrFar(target_offset);
}
}
void Instruction::SetBranchImmTarget(Instruction* target) {
DCHECK(IsAligned(DistanceTo(target), kInstructionSize));
Instr branch_imm = 0;
uint32_t imm_mask = 0;
ptrdiff_t offset = DistanceTo(target) >> kInstructionSizeLog2;
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::SetImmLLiteral(Instruction* source) {
DCHECK(IsAligned(DistanceTo(source), kInstructionSize));
ptrdiff_t offset = DistanceTo(source) >> kLoadLiteralScaleLog2;
Instr imm = Assembler::ImmLLiteral(offset);
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() == xzr.code());
// 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;
}
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_ARM64