Google Git
Sign in
android / platform / external / vixl / l-preview / . / src / a64 / macro-assembler-a64.cc
blob: dcf06c6d714b80450762830a85f96836fa710ef4 [file] [log] [blame]
// Copyright 2013, ARM Limited
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// * Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// * Neither the name of ARM Limited nor the names of its contributors may be
// used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include "a64/macro-assembler-a64.h"
namespace vixl {
LiteralPool::LiteralPool(Assembler* assm)
: assm_(assm), first_use_(-1), monitor_(0) {
}
LiteralPool::~LiteralPool() {
VIXL_ASSERT(IsEmpty());
VIXL_ASSERT(!IsBlocked());
}
void LiteralPool::Reset() {
std::vector<RawLiteral*>::iterator it, end;
for (it = entries_.begin(), end = entries_.end(); it != end; ++it) {
delete *it;
}
entries_.clear();
first_use_ = -1;
monitor_ = 0;
}
size_t LiteralPool::Size() const {
size_t size = 0;
std::vector<RawLiteral*>::const_iterator it, end;
for (it = entries_.begin(), end = entries_.end(); it != end; ++it) {
size += (*it)->size();
}
// account for the pool header.
return size + kInstructionSize;
}
void LiteralPool::Release() {
if (--monitor_ == 0) {
// Has the literal pool been blocked for too long?
VIXL_ASSERT(assm_->CursorOffset() < MaxCursorOffset());
}
}
void LiteralPool::CheckEmitFor(size_t amount, EmitOption option) {
if (IsEmpty() || IsBlocked()) return;
ptrdiff_t distance = assm_->CursorOffset() + amount - first_use_;
if (distance >= kRecommendedLiteralPoolRange) {
Emit(option);
}
}
void LiteralPool::Emit(EmitOption option) {
// There is an issue if we are asked to emit a blocked or empty pool.
VIXL_ASSERT(!IsBlocked());
VIXL_ASSERT(!IsEmpty());
size_t pool_size = Size();
size_t emit_size = pool_size;
if (option == kBranchRequired) emit_size += kInstructionSize;
Label end_of_pool;
CodeBufferCheckScope guard(assm_,
emit_size,
CodeBufferCheckScope::kCheck,
CodeBufferCheckScope::kExactSize);
if (option == kBranchRequired) assm_->b(&end_of_pool);
// Marker indicating the size of the literal pool in 32-bit words.
VIXL_ASSERT((pool_size % kWRegSizeInBytes) == 0);
assm_->ldr(xzr, pool_size / kWRegSizeInBytes);
// Now populate the literal pool.
std::vector<RawLiteral*>::iterator it, end;
for (it = entries_.begin(), end = entries_.end(); it != end; ++it) {
VIXL_ASSERT((*it)->IsUsed());
assm_->place(*it);
delete *it;
}
if (option == kBranchRequired) assm_->bind(&end_of_pool);
entries_.clear();
first_use_ = -1;
}
ptrdiff_t LiteralPool::NextCheckOffset() {
if (IsEmpty()) {
return assm_->CursorOffset() + kRecommendedLiteralPoolRange;
}
VIXL_ASSERT(
((assm_->CursorOffset() - first_use_) < kRecommendedLiteralPoolRange) ||
IsBlocked());
return first_use_ + kRecommendedLiteralPoolRange;
}
EmissionCheckScope::EmissionCheckScope(MacroAssembler* masm, size_t size) {
masm->EnsureEmitFor(size);
#ifdef DEBUG
masm_ = masm;
masm->Bind(&start_);
size_ = size;
masm->AcquireBuffer();
#endif
}
EmissionCheckScope::~EmissionCheckScope() {
#ifdef DEBUG
masm_->ReleaseBuffer();
VIXL_ASSERT(masm_->SizeOfCodeGeneratedSince(&start_) <= size_);
#endif
}
MacroAssembler::MacroAssembler(size_t capacity,
PositionIndependentCodeOption pic)
: Assembler(capacity, pic),
#ifdef DEBUG
allow_macro_instructions_(true),
#endif
sp_(sp),
tmp_list_(ip0, ip1),
fptmp_list_(d31),
literal_pool_(this) {
checkpoint_ = NextCheckOffset();
}
MacroAssembler::MacroAssembler(byte * buffer,
size_t capacity,
PositionIndependentCodeOption pic)
: Assembler(buffer, capacity, pic),
#ifdef DEBUG
allow_macro_instructions_(true),
#endif
sp_(sp),
tmp_list_(ip0, ip1),
fptmp_list_(d31),
literal_pool_(this) {
checkpoint_ = NextCheckOffset();
}
MacroAssembler::~MacroAssembler() {
}
void MacroAssembler::Reset() {
Assembler::Reset();
VIXL_ASSERT(!literal_pool_.IsBlocked());
literal_pool_.Reset();
checkpoint_ = NextCheckOffset();
}
void MacroAssembler::FinalizeCode() {
if (!literal_pool_.IsEmpty()) literal_pool_.Emit();
Assembler::FinalizeCode();
}
void MacroAssembler::B(Label* label, BranchType type, Register reg, int bit) {
VIXL_ASSERT((reg.Is(NoReg) || (type >= kBranchTypeFirstUsingReg)) &&
((bit == -1) || (type >= kBranchTypeFirstUsingBit)));
if (kBranchTypeFirstCondition <= type && type <= kBranchTypeLastCondition) {
B(static_cast<Condition>(type), label);
} else {
switch (type) {
case always: B(label); break;
case never: break;
case reg_zero: Cbz(reg, label); break;
case reg_not_zero: Cbnz(reg, label); break;
case reg_bit_clear: Tbz(reg, bit, label); break;
case reg_bit_set: Tbnz(reg, bit, label); break;
default:
VIXL_UNREACHABLE();
}
}
}
void MacroAssembler::And(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, AND);
}
void MacroAssembler::Ands(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, ANDS);
}
void MacroAssembler::Tst(const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
Ands(AppropriateZeroRegFor(rn), rn, operand);
}
void MacroAssembler::Bic(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, BIC);
}
void MacroAssembler::Bics(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, BICS);
}
void MacroAssembler::Orr(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, ORR);
}
void MacroAssembler::Orn(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, ORN);
}
void MacroAssembler::Eor(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, EOR);
}
void MacroAssembler::Eon(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
LogicalMacro(rd, rn, operand, EON);
}
void MacroAssembler::LogicalMacro(const Register& rd,
const Register& rn,
const Operand& operand,
LogicalOp op) {
// The worst case for size is logical immediate to sp:
// * up to 4 instructions to materialise the constant
// * 1 instruction to do the operation
// * 1 instruction to move to sp
MacroEmissionCheckScope guard(this);
UseScratchRegisterScope temps(this);
if (operand.IsImmediate()) {
int64_t immediate = operand.immediate();
unsigned reg_size = rd.size();
// If the operation is NOT, invert the operation and immediate.
if ((op & NOT) == NOT) {
op = static_cast<LogicalOp>(op & ~NOT);
immediate = ~immediate;
}
// Ignore the top 32 bits of an immediate if we're moving to a W register.
if (rd.Is32Bits()) {
// Check that the top 32 bits are consistent.
VIXL_ASSERT(((immediate >> kWRegSize) == 0) ||
((immediate >> kWRegSize) == -1));
immediate &= kWRegMask;
}
VIXL_ASSERT(rd.Is64Bits() || is_uint32(immediate));
// Special cases for all set or all clear immediates.
if (immediate == 0) {
switch (op) {
case AND:
Mov(rd, 0);
return;
case ORR: // Fall through.
case EOR:
Mov(rd, rn);
return;
case ANDS: // Fall through.
case BICS:
break;
default:
VIXL_UNREACHABLE();
}
} else if ((rd.Is64Bits() && (immediate == -1)) ||
(rd.Is32Bits() && (immediate == 0xffffffff))) {
switch (op) {
case AND:
Mov(rd, rn);
return;
case ORR:
Mov(rd, immediate);
return;
case EOR:
Mvn(rd, rn);
return;
case ANDS: // Fall through.
case BICS:
break;
default:
VIXL_UNREACHABLE();
}
}
unsigned n, imm_s, imm_r;
if (IsImmLogical(immediate, reg_size, &n, &imm_s, &imm_r)) {
// Immediate can be encoded in the instruction.
LogicalImmediate(rd, rn, n, imm_s, imm_r, op);
} else {
// Immediate can't be encoded: synthesize using move immediate.
Register temp = temps.AcquireSameSizeAs(rn);
Operand imm_operand = MoveImmediateForShiftedOp(temp, immediate);
if (rd.Is(sp)) {
// If rd is the stack pointer we cannot use it as the destination
// register so we use the temp register as an intermediate again.
Logical(temp, rn, imm_operand, op);
Mov(sp, temp);
} else {
Logical(rd, rn, imm_operand, op);
}
}
} else if (operand.IsExtendedRegister()) {
VIXL_ASSERT(operand.reg().size() <= rd.size());
// Add/sub extended supports shift <= 4. We want to support exactly the
// same modes here.
VIXL_ASSERT(operand.shift_amount() <= 4);
VIXL_ASSERT(operand.reg().Is64Bits() ||
((operand.extend() != UXTX) && (operand.extend() != SXTX)));
temps.Exclude(operand.reg());
Register temp = temps.AcquireSameSizeAs(rn);
EmitExtendShift(temp, operand.reg(), operand.extend(),
operand.shift_amount());
Logical(rd, rn, Operand(temp), op);
} else {
// The operand can be encoded in the instruction.
VIXL_ASSERT(operand.IsShiftedRegister());
Logical(rd, rn, operand, op);
}
}
void MacroAssembler::Mov(const Register& rd,
const Operand& operand,
DiscardMoveMode discard_mode) {
VIXL_ASSERT(allow_macro_instructions_);
// The worst case for size is mov immediate with up to 4 instructions.
MacroEmissionCheckScope guard(this);
if (operand.IsImmediate()) {
// Call the macro assembler for generic immediates.
Mov(rd, operand.immediate());
} else if (operand.IsShiftedRegister() && (operand.shift_amount() != 0)) {
// Emit a shift instruction if moving a shifted register. This operation
// could also be achieved using an orr instruction (like orn used by Mvn),
// but using a shift instruction makes the disassembly clearer.
EmitShift(rd, operand.reg(), operand.shift(), operand.shift_amount());
} else if (operand.IsExtendedRegister()) {
// Emit an extend instruction if moving an extended register. This handles
// extend with post-shift operations, too.
EmitExtendShift(rd, operand.reg(), operand.extend(),
operand.shift_amount());
} else {
// Otherwise, emit a register move only if the registers are distinct, or
// if they are not X registers.
//
// Note that mov(w0, w0) is not a no-op because it clears the top word of
// x0. A flag is provided (kDiscardForSameWReg) if a move between the same W
// registers is not required to clear the top word of the X register. In
// this case, the instruction is discarded.
//
// If the sp is an operand, add #0 is emitted, otherwise, orr #0.
if (!rd.Is(operand.reg()) || (rd.Is32Bits() &&
(discard_mode == kDontDiscardForSameWReg))) {
mov(rd, operand.reg());
}
}
}
void MacroAssembler::Mvn(const Register& rd, const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
// The worst case for size is mvn immediate with up to 4 instructions.
MacroEmissionCheckScope guard(this);
if (operand.IsImmediate()) {
// Call the macro assembler for generic immediates.
Mvn(rd, operand.immediate());
} else if (operand.IsExtendedRegister()) {
UseScratchRegisterScope temps(this);
temps.Exclude(operand.reg());
// Emit two instructions for the extend case. This differs from Mov, as
// the extend and invert can't be achieved in one instruction.
Register temp = temps.AcquireSameSizeAs(rd);
EmitExtendShift(temp, operand.reg(), operand.extend(),
operand.shift_amount());
mvn(rd, Operand(temp));
} else {
// Otherwise, register and shifted register cases can be handled by the
// assembler directly, using orn.
mvn(rd, operand);
}
}
void MacroAssembler::Mov(const Register& rd, uint64_t imm) {
VIXL_ASSERT(allow_macro_instructions_);
VIXL_ASSERT(is_uint32(imm) || is_int32(imm) || rd.Is64Bits());
// The worst case for size is mov 64-bit immediate to sp:
// * up to 4 instructions to materialise the constant
// * 1 instruction to move to sp
MacroEmissionCheckScope guard(this);
// Immediates on Aarch64 can be produced using an initial value, and zero to
// three move keep operations.
//
// Initial values can be generated with:
// 1. 64-bit move zero (movz).
// 2. 32-bit move inverted (movn).
// 3. 64-bit move inverted.
// 4. 32-bit orr immediate.
// 5. 64-bit orr immediate.
// Move-keep may then be used to modify each of the 16-bit half words.
//
// The code below supports all five initial value generators, and
// applying move-keep operations to move-zero and move-inverted initial
// values.
// Try to move the immediate in one instruction, and if that fails, switch to
// using multiple instructions.
if (!TryOneInstrMoveImmediate(rd, imm)) {
unsigned reg_size = rd.size();
// Generic immediate case. Imm will be represented by
// [imm3, imm2, imm1, imm0], where each imm is 16 bits.
// A move-zero or move-inverted is generated for the first non-zero or
// non-0xffff immX, and a move-keep for subsequent non-zero immX.
uint64_t ignored_halfword = 0;
bool invert_move = false;
// If the number of 0xffff halfwords is greater than the number of 0x0000
// halfwords, it's more efficient to use move-inverted.
if (CountClearHalfWords(~imm, reg_size) >
CountClearHalfWords(imm, reg_size)) {
ignored_halfword = 0xffff;
invert_move = true;
}
// Mov instructions can't move values into the stack pointer, so set up a
// temporary register, if needed.
UseScratchRegisterScope temps(this);
Register temp = rd.IsSP() ? temps.AcquireSameSizeAs(rd) : rd;
// Iterate through the halfwords. Use movn/movz for the first non-ignored
// halfword, and movk for subsequent halfwords.
VIXL_ASSERT((reg_size % 16) == 0);
bool first_mov_done = false;
for (unsigned i = 0; i < (temp.size() / 16); i++) {
uint64_t imm16 = (imm >> (16 * i)) & 0xffff;
if (imm16 != ignored_halfword) {
if (!first_mov_done) {
if (invert_move) {
movn(temp, ~imm16 & 0xffff, 16 * i);
} else {
movz(temp, imm16, 16 * i);
}
first_mov_done = true;
} else {
// Construct a wider constant.
movk(temp, imm16, 16 * i);
}
}
}
VIXL_ASSERT(first_mov_done);
// Move the temporary if the original destination register was the stack
// pointer.
if (rd.IsSP()) {
mov(rd, temp);
}
}
}
unsigned MacroAssembler::CountClearHalfWords(uint64_t imm, unsigned reg_size) {
VIXL_ASSERT((reg_size % 8) == 0);
int count = 0;
for (unsigned i = 0; i < (reg_size / 16); i++) {
if ((imm & 0xffff) == 0) {
count++;
}
imm >>= 16;
}
return count;
}
// The movz instruction can generate immediates containing an arbitrary 16-bit
// value, with remaining bits clear, eg. 0x00001234, 0x0000123400000000.
bool MacroAssembler::IsImmMovz(uint64_t imm, unsigned reg_size) {
VIXL_ASSERT((reg_size == kXRegSize) || (reg_size == kWRegSize));
return CountClearHalfWords(imm, reg_size) >= ((reg_size / 16) - 1);
}
// The movn instruction can generate immediates containing an arbitrary 16-bit
// value, with remaining bits set, eg. 0xffff1234, 0xffff1234ffffffff.
bool MacroAssembler::IsImmMovn(uint64_t imm, unsigned reg_size) {
return IsImmMovz(~imm, reg_size);
}
void MacroAssembler::Ccmp(const Register& rn,
const Operand& operand,
StatusFlags nzcv,
Condition cond) {
VIXL_ASSERT(allow_macro_instructions_);
if (operand.IsImmediate() && (operand.immediate() < 0)) {
ConditionalCompareMacro(rn, -operand.immediate(), nzcv, cond, CCMN);
} else {
ConditionalCompareMacro(rn, operand, nzcv, cond, CCMP);
}
}
void MacroAssembler::Ccmn(const Register& rn,
const Operand& operand,
StatusFlags nzcv,
Condition cond) {
VIXL_ASSERT(allow_macro_instructions_);
if (operand.IsImmediate() && (operand.immediate() < 0)) {
ConditionalCompareMacro(rn, -operand.immediate(), nzcv, cond, CCMP);
} else {
ConditionalCompareMacro(rn, operand, nzcv, cond, CCMN);
}
}
void MacroAssembler::ConditionalCompareMacro(const Register& rn,
const Operand& operand,
StatusFlags nzcv,
Condition cond,
ConditionalCompareOp op) {
VIXL_ASSERT((cond != al) && (cond != nv));
// The worst case for size is ccmp immediate:
// * up to 4 instructions to materialise the constant
// * 1 instruction for ccmp
MacroEmissionCheckScope guard(this);
if ((operand.IsShiftedRegister() && (operand.shift_amount() == 0)) ||
(operand.IsImmediate() && IsImmConditionalCompare(operand.immediate()))) {
// The immediate can be encoded in the instruction, or the operand is an
// unshifted register: call the assembler.
ConditionalCompare(rn, operand, nzcv, cond, op);
} else {
UseScratchRegisterScope temps(this);
// The operand isn't directly supported by the instruction: perform the
// operation on a temporary register.
Register temp = temps.AcquireSameSizeAs(rn);
Mov(temp, operand);
ConditionalCompare(rn, temp, nzcv, cond, op);
}
}
void MacroAssembler::Csel(const Register& rd,
const Register& rn,
const Operand& operand,
Condition cond) {
VIXL_ASSERT(allow_macro_instructions_);
VIXL_ASSERT(!rd.IsZero());
VIXL_ASSERT(!rn.IsZero());
VIXL_ASSERT((cond != al) && (cond != nv));
// The worst case for size is csel immediate:
// * up to 4 instructions to materialise the constant
// * 1 instruction for csel
MacroEmissionCheckScope guard(this);
if (operand.IsImmediate()) {
// Immediate argument. Handle special cases of 0, 1 and -1 using zero
// register.
int64_t imm = operand.immediate();
Register zr = AppropriateZeroRegFor(rn);
if (imm == 0) {
csel(rd, rn, zr, cond);
} else if (imm == 1) {
csinc(rd, rn, zr, cond);
} else if (imm == -1) {
csinv(rd, rn, zr, cond);
} else {
UseScratchRegisterScope temps(this);
Register temp = temps.AcquireSameSizeAs(rn);
Mov(temp, operand.immediate());
csel(rd, rn, temp, cond);
}
} else if (operand.IsShiftedRegister() && (operand.shift_amount() == 0)) {
// Unshifted register argument.
csel(rd, rn, operand.reg(), cond);
} else {
// All other arguments.
UseScratchRegisterScope temps(this);
Register temp = temps.AcquireSameSizeAs(rn);
Mov(temp, operand);
csel(rd, rn, temp, cond);
}
}
void MacroAssembler::Add(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
if (operand.IsImmediate() && (operand.immediate() < 0) &&
IsImmAddSub(-operand.immediate())) {
AddSubMacro(rd, rn, -operand.immediate(), LeaveFlags, SUB);
} else {
AddSubMacro(rd, rn, operand, LeaveFlags, ADD);
}
}
void MacroAssembler::Adds(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
if (operand.IsImmediate() && (operand.immediate() < 0) &&
IsImmAddSub(-operand.immediate())) {
AddSubMacro(rd, rn, -operand.immediate(), SetFlags, SUB);
} else {
AddSubMacro(rd, rn, operand, SetFlags, ADD);
}
}
void MacroAssembler::Sub(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
if (operand.IsImmediate() && (operand.immediate() < 0) &&
IsImmAddSub(-operand.immediate())) {
AddSubMacro(rd, rn, -operand.immediate(), LeaveFlags, ADD);
} else {
AddSubMacro(rd, rn, operand, LeaveFlags, SUB);
}
}
void MacroAssembler::Subs(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
if (operand.IsImmediate() && (operand.immediate() < 0) &&
IsImmAddSub(-operand.immediate())) {
AddSubMacro(rd, rn, -operand.immediate(), SetFlags, ADD);
} else {
AddSubMacro(rd, rn, operand, SetFlags, SUB);
}
}
void MacroAssembler::Cmn(const Register& rn, const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
Adds(AppropriateZeroRegFor(rn), rn, operand);
}
void MacroAssembler::Cmp(const Register& rn, const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
Subs(AppropriateZeroRegFor(rn), rn, operand);
}
void MacroAssembler::Fcmp(const FPRegister& fn, double value) {
VIXL_ASSERT(allow_macro_instructions_);
// The worst case for size is:
// * 1 to materialise the constant, using literal pool if necessary
// * 1 instruction for fcmp
MacroEmissionCheckScope guard(this);
if (value != 0.0) {
UseScratchRegisterScope temps(this);
FPRegister tmp = temps.AcquireSameSizeAs(fn);
Fmov(tmp, value);
fcmp(fn, tmp);
} else {
fcmp(fn, value);
}
}
void MacroAssembler::Fmov(FPRegister fd, double imm) {
VIXL_ASSERT(allow_macro_instructions_);
// Floating point immediates are loaded through the literal pool.
MacroEmissionCheckScope guard(this);
if (fd.Is32Bits()) {
Fmov(fd, static_cast<float>(imm));
return;
}
VIXL_ASSERT(fd.Is64Bits());
if (IsImmFP64(imm)) {
fmov(fd, imm);
} else if ((imm == 0.0) && (copysign(1.0, imm) == 1.0)) {
fmov(fd, xzr);
} else {
RawLiteral* literal = literal_pool_.Add(imm);
ldr(fd, literal);
}
}
void MacroAssembler::Fmov(FPRegister fd, float imm) {
VIXL_ASSERT(allow_macro_instructions_);
// Floating point immediates are loaded through the literal pool.
MacroEmissionCheckScope guard(this);
if (fd.Is64Bits()) {
Fmov(fd, static_cast<double>(imm));
return;
}
VIXL_ASSERT(fd.Is32Bits());
if (IsImmFP32(imm)) {
fmov(fd, imm);
} else if ((imm == 0.0) && (copysign(1.0, imm) == 1.0)) {
fmov(fd, wzr);
} else {
RawLiteral* literal = literal_pool_.Add(imm);
ldr(fd, literal);
}
}
void MacroAssembler::Neg(const Register& rd,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
if (operand.IsImmediate()) {
Mov(rd, -operand.immediate());
} else {
Sub(rd, AppropriateZeroRegFor(rd), operand);
}
}
void MacroAssembler::Negs(const Register& rd,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
Subs(rd, AppropriateZeroRegFor(rd), operand);
}
bool MacroAssembler::TryOneInstrMoveImmediate(const Register& dst,
int64_t imm) {
unsigned n, imm_s, imm_r;
int reg_size = dst.size();
if (IsImmMovz(imm, reg_size) && !dst.IsSP()) {
// Immediate can be represented in a move zero instruction. Movz can't write
// to the stack pointer.
movz(dst, imm);
return true;
} else if (IsImmMovn(imm, reg_size) && !dst.IsSP()) {
// Immediate can be represented in a move negative instruction. Movn can't
// write to the stack pointer.
movn(dst, dst.Is64Bits() ? ~imm : (~imm & kWRegMask));
return true;
} else if (IsImmLogical(imm, reg_size, &n, &imm_s, &imm_r)) {
// Immediate can be represented in a logical orr instruction.
VIXL_ASSERT(!dst.IsZero());
LogicalImmediate(dst, AppropriateZeroRegFor(dst), n, imm_s, imm_r, ORR);
return true;
}
return false;
}
Operand MacroAssembler::MoveImmediateForShiftedOp(const Register& dst,
int64_t imm) {
int reg_size = dst.size();
// Encode the immediate in a single move instruction, if possible.
if (TryOneInstrMoveImmediate(dst, imm)) {
// The move was successful; nothing to do here.
} else {
// Pre-shift the immediate to the least-significant bits of the register.
int shift_low = CountTrailingZeros(imm, reg_size);
int64_t imm_low = imm >> shift_low;
// Pre-shift the immediate to the most-significant bits of the register,
// inserting set bits in the least-significant bits.
int shift_high = CountLeadingZeros(imm, reg_size);
int64_t imm_high = (imm << shift_high) | ((1 << shift_high) - 1);
if (TryOneInstrMoveImmediate(dst, imm_low)) {
// The new immediate has been moved into the destination's low bits:
// return a new leftward-shifting operand.
return Operand(dst, LSL, shift_low);
} else if (TryOneInstrMoveImmediate(dst, imm_high)) {
// The new immediate has been moved into the destination's high bits:
// return a new rightward-shifting operand.
return Operand(dst, LSR, shift_high);
} else {
Mov(dst, imm);
}
}
return Operand(dst);
}
void MacroAssembler::AddSubMacro(const Register& rd,
const Register& rn,
const Operand& operand,
FlagsUpdate S,
AddSubOp op) {
// Worst case is add/sub immediate:
// * up to 4 instructions to materialise the constant
// * 1 instruction for add/sub
MacroEmissionCheckScope guard(this);
if (operand.IsZero() && rd.Is(rn) && rd.Is64Bits() && rn.Is64Bits() &&
(S == LeaveFlags)) {
// The instruction would be a nop. Avoid generating useless code.
return;
}
if ((operand.IsImmediate() && !IsImmAddSub(operand.immediate())) ||
(rn.IsZero() && !operand.IsShiftedRegister()) ||
(operand.IsShiftedRegister() && (operand.shift() == ROR))) {
UseScratchRegisterScope temps(this);
Register temp = temps.AcquireSameSizeAs(rn);
if (operand.IsImmediate()) {
Operand imm_operand =
MoveImmediateForShiftedOp(temp, operand.immediate());
AddSub(rd, rn, imm_operand, S, op);
} else {
Mov(temp, operand);
AddSub(rd, rn, temp, S, op);
}
} else {
AddSub(rd, rn, operand, S, op);
}
}
void MacroAssembler::Adc(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
AddSubWithCarryMacro(rd, rn, operand, LeaveFlags, ADC);
}
void MacroAssembler::Adcs(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
AddSubWithCarryMacro(rd, rn, operand, SetFlags, ADC);
}
void MacroAssembler::Sbc(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
AddSubWithCarryMacro(rd, rn, operand, LeaveFlags, SBC);
}
void MacroAssembler::Sbcs(const Register& rd,
const Register& rn,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
AddSubWithCarryMacro(rd, rn, operand, SetFlags, SBC);
}
void MacroAssembler::Ngc(const Register& rd,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
Register zr = AppropriateZeroRegFor(rd);
Sbc(rd, zr, operand);
}
void MacroAssembler::Ngcs(const Register& rd,
const Operand& operand) {
VIXL_ASSERT(allow_macro_instructions_);
Register zr = AppropriateZeroRegFor(rd);
Sbcs(rd, zr, operand);
}
void MacroAssembler::AddSubWithCarryMacro(const Register& rd,
const Register& rn,
const Operand& operand,
FlagsUpdate S,
AddSubWithCarryOp op) {
VIXL_ASSERT(rd.size() == rn.size());
// Worst case is addc/subc immediate:
// * up to 4 instructions to materialise the constant
// * 1 instruction for add/sub
MacroEmissionCheckScope guard(this);
UseScratchRegisterScope temps(this);
if (operand.IsImmediate() ||
(operand.IsShiftedRegister() && (operand.shift() == ROR))) {
// Add/sub with carry (immediate or ROR shifted register.)
Register temp = temps.AcquireSameSizeAs(rn);
Mov(temp, operand);
AddSubWithCarry(rd, rn, Operand(temp), S, op);
} else if (operand.IsShiftedRegister() && (operand.shift_amount() != 0)) {
// Add/sub with carry (shifted register).
VIXL_ASSERT(operand.reg().size() == rd.size());
VIXL_ASSERT(operand.shift() != ROR);
VIXL_ASSERT(is_uintn(rd.size() == kXRegSize ? kXRegSizeLog2 : kWRegSizeLog2,
operand.shift_amount()));
temps.Exclude(operand.reg());
Register temp = temps.AcquireSameSizeAs(rn);
EmitShift(temp, operand.reg(), operand.shift(), operand.shift_amount());
AddSubWithCarry(rd, rn, Operand(temp), S, op);
} else if (operand.IsExtendedRegister()) {
// Add/sub with carry (extended register).
VIXL_ASSERT(operand.reg().size() <= rd.size());
// Add/sub extended supports a shift <= 4. We want to support exactly the
// same modes.
VIXL_ASSERT(operand.shift_amount() <= 4);
VIXL_ASSERT(operand.reg().Is64Bits() ||
((operand.extend() != UXTX) && (operand.extend() != SXTX)));
temps.Exclude(operand.reg());
Register temp = temps.AcquireSameSizeAs(rn);
EmitExtendShift(temp, operand.reg(), operand.extend(),
operand.shift_amount());
AddSubWithCarry(rd, rn, Operand(temp), S, op);
} else {
// The addressing mode is directly supported by the instruction.
AddSubWithCarry(rd, rn, operand, S, op);
}
}
#define DEFINE_FUNCTION(FN, REGTYPE, REG, OP) \
void MacroAssembler::FN(const REGTYPE REG, const MemOperand& addr) { \
VIXL_ASSERT(allow_macro_instructions_); \
LoadStoreMacro(REG, addr, OP); \
}
LS_MACRO_LIST(DEFINE_FUNCTION)
#undef DEFINE_FUNCTION
void MacroAssembler::LoadStoreMacro(const CPURegister& rt,
const MemOperand& addr,
LoadStoreOp op) {
// Worst case is ldr/str pre/post index:
// * 1 instruction for ldr/str
// * up to 4 instructions to materialise the constant
// * 1 instruction to update the base
MacroEmissionCheckScope guard(this);
int64_t offset = addr.offset();
LSDataSize size = CalcLSDataSize(op);
// Check if an immediate offset fits in the immediate field of the
// appropriate instruction. If not, emit two instructions to perform
// the operation.
if (addr.IsImmediateOffset() && !IsImmLSScaled(offset, size) &&
!IsImmLSUnscaled(offset)) {
// Immediate offset that can't be encoded using unsigned or unscaled
// addressing modes.
UseScratchRegisterScope temps(this);
Register temp = temps.AcquireSameSizeAs(addr.base());
Mov(temp, addr.offset());
LoadStore(rt, MemOperand(addr.base(), temp), op);
} else if (addr.IsPostIndex() && !IsImmLSUnscaled(offset)) {
// Post-index beyond unscaled addressing range.
LoadStore(rt, MemOperand(addr.base()), op);
Add(addr.base(), addr.base(), Operand(offset));
} else if (addr.IsPreIndex() && !IsImmLSUnscaled(offset)) {
// Pre-index beyond unscaled addressing range.
Add(addr.base(), addr.base(), Operand(offset));
LoadStore(rt, MemOperand(addr.base()), op);
} else {
// Encodable in one load/store instruction.
LoadStore(rt, addr, op);
}
}
#define DEFINE_FUNCTION(FN, REGTYPE, REG, REG2, OP) \
void MacroAssembler::FN(const REGTYPE REG, \
const REGTYPE REG2, \
const MemOperand& addr) { \
VIXL_ASSERT(allow_macro_instructions_); \
LoadStorePairMacro(REG, REG2, addr, OP); \
}
LSPAIR_MACRO_LIST(DEFINE_FUNCTION)
#undef DEFINE_FUNCTION
void MacroAssembler::LoadStorePairMacro(const CPURegister& rt,
const CPURegister& rt2,
const MemOperand& addr,
LoadStorePairOp op) {
// TODO(all): Should we support register offset for load-store-pair?
VIXL_ASSERT(!addr.IsRegisterOffset());
// Worst case is ldp/stp immediate:
// * 1 instruction for ldp/stp
// * up to 4 instructions to materialise the constant
// * 1 instruction to update the base
MacroEmissionCheckScope guard(this);
int64_t offset = addr.offset();
LSDataSize size = CalcLSPairDataSize(op);
// Check if the offset fits in the immediate field of the appropriate
// instruction. If not, emit two instructions to perform the operation.
if (IsImmLSPair(offset, size)) {
// Encodable in one load/store pair instruction.
LoadStorePair(rt, rt2, addr, op);
} else {
Register base = addr.base();
if (addr.IsImmediateOffset()) {
UseScratchRegisterScope temps(this);
Register temp = temps.AcquireSameSizeAs(base);
Add(temp, base, offset);
LoadStorePair(rt, rt2, MemOperand(temp), op);
} else if (addr.IsPostIndex()) {
LoadStorePair(rt, rt2, MemOperand(base), op);
Add(base, base, offset);
} else {
VIXL_ASSERT(addr.IsPreIndex());
Add(base, base, offset);
LoadStorePair(rt, rt2, MemOperand(base), op);
}
}
}
void MacroAssembler::Push(const CPURegister& src0, const CPURegister& src1,
const CPURegister& src2, const CPURegister& src3) {
VIXL_ASSERT(allow_macro_instructions_);
VIXL_ASSERT(AreSameSizeAndType(src0, src1, src2, src3));
VIXL_ASSERT(src0.IsValid());
int count = 1 + src1.IsValid() + src2.IsValid() + src3.IsValid();
int size = src0.SizeInBytes();
PrepareForPush(count, size);
PushHelper(count, size, src0, src1, src2, src3);
}
void MacroAssembler::Pop(const CPURegister& dst0, const CPURegister& dst1,
const CPURegister& dst2, const CPURegister& dst3) {
// It is not valid to pop into the same register more than once in one
// instruction, not even into the zero register.
VIXL_ASSERT(allow_macro_instructions_);
VIXL_ASSERT(!AreAliased(dst0, dst1, dst2, dst3));
VIXL_ASSERT(AreSameSizeAndType(dst0, dst1, dst2, dst3));
VIXL_ASSERT(dst0.IsValid());
int count = 1 + dst1.IsValid() + dst2.IsValid() + dst3.IsValid();
int size = dst0.SizeInBytes();
PrepareForPop(count, size);
PopHelper(count, size, dst0, dst1, dst2, dst3);
}
void MacroAssembler::PushCPURegList(CPURegList registers) {
int size = registers.RegisterSizeInBytes();
PrepareForPush(registers.Count(), size);
// Push up to four registers at a time because if the current stack pointer is
// sp and reg_size is 32, registers must be pushed in blocks of four in order
// to maintain the 16-byte alignment for sp.
VIXL_ASSERT(allow_macro_instructions_);
while (!registers.IsEmpty()) {
int count_before = registers.Count();
const CPURegister& src0 = registers.PopHighestIndex();
const CPURegister& src1 = registers.PopHighestIndex();
const CPURegister& src2 = registers.PopHighestIndex();
const CPURegister& src3 = registers.PopHighestIndex();
int count = count_before - registers.Count();
PushHelper(count, size, src0, src1, src2, src3);
}
}
void MacroAssembler::PopCPURegList(CPURegList registers) {
int size = registers.RegisterSizeInBytes();
PrepareForPop(registers.Count(), size);
// Pop up to four registers at a time because if the current stack pointer is
// sp and reg_size is 32, registers must be pushed in blocks of four in order
// to maintain the 16-byte alignment for sp.
VIXL_ASSERT(allow_macro_instructions_);
while (!registers.IsEmpty()) {
int count_before = registers.Count();
const CPURegister& dst0 = registers.PopLowestIndex();
const CPURegister& dst1 = registers.PopLowestIndex();
const CPURegister& dst2 = registers.PopLowestIndex();
const CPURegister& dst3 = registers.PopLowestIndex();
int count = count_before - registers.Count();
PopHelper(count, size, dst0, dst1, dst2, dst3);
}
}
void MacroAssembler::PushMultipleTimes(int count, Register src) {
VIXL_ASSERT(allow_macro_instructions_);
int size = src.SizeInBytes();
PrepareForPush(count, size);
// Push up to four registers at a time if possible because if the current
// stack pointer is sp and the register size is 32, registers must be pushed
// in blocks of four in order to maintain the 16-byte alignment for sp.
while (count >= 4) {
PushHelper(4, size, src, src, src, src);
count -= 4;
}
if (count >= 2) {
PushHelper(2, size, src, src, NoReg, NoReg);
count -= 2;
}
if (count == 1) {
PushHelper(1, size, src, NoReg, NoReg, NoReg);
count -= 1;
}
VIXL_ASSERT(count == 0);
}
void MacroAssembler::PushHelper(int count, int size,
const CPURegister& src0,
const CPURegister& src1,
const CPURegister& src2,
const CPURegister& src3) {
// Ensure that we don't unintentionally modify scratch or debug registers.
// Worst case for size is 2 stp.
InstructionAccurateScope scope(this, 2,
InstructionAccurateScope::kMaximumSize);
VIXL_ASSERT(AreSameSizeAndType(src0, src1, src2, src3));
VIXL_ASSERT(size == src0.SizeInBytes());
// When pushing multiple registers, the store order is chosen such that
// Push(a, b) is equivalent to Push(a) followed by Push(b).
switch (count) {
case 1:
VIXL_ASSERT(src1.IsNone() && src2.IsNone() && src3.IsNone());
str(src0, MemOperand(StackPointer(), -1 * size, PreIndex));
break;
case 2:
VIXL_ASSERT(src2.IsNone() && src3.IsNone());
stp(src1, src0, MemOperand(StackPointer(), -2 * size, PreIndex));
break;
case 3:
VIXL_ASSERT(src3.IsNone());
stp(src2, src1, MemOperand(StackPointer(), -3 * size, PreIndex));
str(src0, MemOperand(StackPointer(), 2 * size));
break;
case 4:
// Skip over 4 * size, then fill in the gap. This allows four W registers
// to be pushed using sp, whilst maintaining 16-byte alignment for sp at
// all times.
stp(src3, src2, MemOperand(StackPointer(), -4 * size, PreIndex));
stp(src1, src0, MemOperand(StackPointer(), 2 * size));
break;
default:
VIXL_UNREACHABLE();
}
}
void MacroAssembler::PopHelper(int count, int size,
const CPURegister& dst0,
const CPURegister& dst1,
const CPURegister& dst2,
const CPURegister& dst3) {
// Ensure that we don't unintentionally modify scratch or debug registers.
// Worst case for size is 2 ldp.
InstructionAccurateScope scope(this, 2,
InstructionAccurateScope::kMaximumSize);
VIXL_ASSERT(AreSameSizeAndType(dst0, dst1, dst2, dst3));
VIXL_ASSERT(size == dst0.SizeInBytes());
// When popping multiple registers, the load order is chosen such that
// Pop(a, b) is equivalent to Pop(a) followed by Pop(b).
switch (count) {
case 1:
VIXL_ASSERT(dst1.IsNone() && dst2.IsNone() && dst3.IsNone());
ldr(dst0, MemOperand(StackPointer(), 1 * size, PostIndex));
break;
case 2:
VIXL_ASSERT(dst2.IsNone() && dst3.IsNone());
ldp(dst0, dst1, MemOperand(StackPointer(), 2 * size, PostIndex));
break;
case 3:
VIXL_ASSERT(dst3.IsNone());
ldr(dst2, MemOperand(StackPointer(), 2 * size));
ldp(dst0, dst1, MemOperand(StackPointer(), 3 * size, PostIndex));
break;
case 4:
// Load the higher addresses first, then load the lower addresses and skip
// the whole block in the second instruction. This allows four W registers
// to be popped using sp, whilst maintaining 16-byte alignment for sp at
// all times.
ldp(dst2, dst3, MemOperand(StackPointer(), 2 * size));
ldp(dst0, dst1, MemOperand(StackPointer(), 4 * size, PostIndex));
break;
default:
VIXL_UNREACHABLE();
}
}
void MacroAssembler::PrepareForPush(int count, int size) {
if (sp.Is(StackPointer())) {
// If the current stack pointer is sp, then it must be aligned to 16 bytes
// on entry and the total size of the specified registers must also be a
// multiple of 16 bytes.
VIXL_ASSERT((count * size) % 16 == 0);
} else {
// Even if the current stack pointer is not the system stack pointer (sp),
// the system stack pointer will still be modified in order to comply with
// ABI rules about accessing memory below the system stack pointer.
BumpSystemStackPointer(count * size);
}
}
void MacroAssembler::PrepareForPop(int count, int size) {
USE(count);
USE(size);
if (sp.Is(StackPointer())) {
// If the current stack pointer is sp, then it must be aligned to 16 bytes
// on entry and the total size of the specified registers must also be a
// multiple of 16 bytes.
VIXL_ASSERT((count * size) % 16 == 0);
}
}
void MacroAssembler::Poke(const Register& src, const Operand& offset) {
VIXL_ASSERT(allow_macro_instructions_);
if (offset.IsImmediate()) {
VIXL_ASSERT(offset.immediate() >= 0);
}
Str(src, MemOperand(StackPointer(), offset));
}
void MacroAssembler::Peek(const Register& dst, const Operand& offset) {
VIXL_ASSERT(allow_macro_instructions_);
if (offset.IsImmediate()) {
VIXL_ASSERT(offset.immediate() >= 0);
}
Ldr(dst, MemOperand(StackPointer(), offset));
}
void MacroAssembler::PeekCPURegList(CPURegList registers, int offset) {
VIXL_ASSERT(!registers.IncludesAliasOf(StackPointer()));
VIXL_ASSERT(offset >= 0);
int size = registers.RegisterSizeInBytes();
while (registers.Count() >= 2) {
const CPURegister& dst0 = registers.PopLowestIndex();
const CPURegister& dst1 = registers.PopLowestIndex();
Ldp(dst0, dst1, MemOperand(StackPointer(), offset));
offset += 2 * size;
}
if (!registers.IsEmpty()) {
Ldr(registers.PopLowestIndex(),
MemOperand(StackPointer(), offset));
}
}
void MacroAssembler::PokeCPURegList(CPURegList registers, int offset) {
VIXL_ASSERT(!registers.IncludesAliasOf(StackPointer()));
VIXL_ASSERT(offset >= 0);
int size = registers.RegisterSizeInBytes();
while (registers.Count() >= 2) {
const CPURegister& dst0 = registers.PopLowestIndex();
const CPURegister& dst1 = registers.PopLowestIndex();
Stp(dst0, dst1, MemOperand(StackPointer(), offset));
offset += 2 * size;
}
if (!registers.IsEmpty()) {
Str(registers.PopLowestIndex(),
MemOperand(StackPointer(), offset));
}
}
void MacroAssembler::Claim(const Operand& size) {
VIXL_ASSERT(allow_macro_instructions_);
if (size.IsZero()) {
return;
}
if (size.IsImmediate()) {
VIXL_ASSERT(size.immediate() > 0);
if (sp.Is(StackPointer())) {
VIXL_ASSERT((size.immediate() % 16) == 0);
}
}
if (!sp.Is(StackPointer())) {
BumpSystemStackPointer(size);
}
Sub(StackPointer(), StackPointer(), size);
}
void MacroAssembler::Drop(const Operand& size) {
VIXL_ASSERT(allow_macro_instructions_);
if (size.IsZero()) {
return;
}
if (size.IsImmediate()) {
VIXL_ASSERT(size.immediate() > 0);
if (sp.Is(StackPointer())) {
VIXL_ASSERT((size.immediate() % 16) == 0);
}
}
Add(StackPointer(), StackPointer(), size);
}
void MacroAssembler::PushCalleeSavedRegisters() {
// Ensure that the macro-assembler doesn't use any scratch registers.
// 10 stp will be emitted.
// TODO(all): Should we use GetCalleeSaved and SavedFP.
InstructionAccurateScope scope(this, 10);
// This method must not be called unless the current stack pointer is sp.
VIXL_ASSERT(sp.Is(StackPointer()));
MemOperand tos(sp, -2 * kXRegSizeInBytes, PreIndex);
stp(x29, x30, tos);
stp(x27, x28, tos);
stp(x25, x26, tos);
stp(x23, x24, tos);
stp(x21, x22, tos);
stp(x19, x20, tos);
stp(d14, d15, tos);
stp(d12, d13, tos);
stp(d10, d11, tos);
stp(d8, d9, tos);
}
void MacroAssembler::PopCalleeSavedRegisters() {
// Ensure that the macro-assembler doesn't use any scratch registers.
// 10 ldp will be emitted.
// TODO(all): Should we use GetCalleeSaved and SavedFP.
InstructionAccurateScope scope(this, 10);
// This method must not be called unless the current stack pointer is sp.
VIXL_ASSERT(sp.Is(StackPointer()));
MemOperand tos(sp, 2 * kXRegSizeInBytes, PostIndex);
ldp(d8, d9, tos);
ldp(d10, d11, tos);
ldp(d12, d13, tos);
ldp(d14, d15, tos);
ldp(x19, x20, tos);
ldp(x21, x22, tos);
ldp(x23, x24, tos);
ldp(x25, x26, tos);
ldp(x27, x28, tos);
ldp(x29, x30, tos);
}
void MacroAssembler::BumpSystemStackPointer(const Operand& space) {
VIXL_ASSERT(!sp.Is(StackPointer()));
// TODO: Several callers rely on this not using scratch registers, so we use
// the assembler directly here. However, this means that large immediate
// values of 'space' cannot be handled.
InstructionAccurateScope scope(this, 1);
sub(sp, StackPointer(), space);
}
// This is the main Printf implementation. All callee-saved registers are
// preserved, but NZCV and the caller-saved registers may be clobbered.
void MacroAssembler::PrintfNoPreserve(const char * format,
const CPURegister& arg0,
const CPURegister& arg1,
const CPURegister& arg2,
const CPURegister& arg3) {
// We cannot handle a caller-saved stack pointer. It doesn't make much sense
// in most cases anyway, so this restriction shouldn't be too serious.
VIXL_ASSERT(!kCallerSaved.IncludesAliasOf(StackPointer()));
// The provided arguments, and their proper PCS registers.
CPURegister args[kPrintfMaxArgCount] = {arg0, arg1, arg2, arg3};
CPURegister pcs[kPrintfMaxArgCount];
int arg_count = kPrintfMaxArgCount;
// The PCS varargs registers for printf. Note that x0 is used for the printf
// format string.
static const CPURegList kPCSVarargs =
CPURegList(CPURegister::kRegister, kXRegSize, 1, arg_count);
static const CPURegList kPCSVarargsFP =
CPURegList(CPURegister::kFPRegister, kDRegSize, 0, arg_count - 1);
// We can use caller-saved registers as scratch values, except for the
// arguments and the PCS registers where they might need to go.
UseScratchRegisterScope temps(this);
temps.Include(kCallerSaved);
temps.Include(kCallerSavedFP);
temps.Exclude(kPCSVarargs);
temps.Exclude(kPCSVarargsFP);
temps.Exclude(arg0, arg1, arg2, arg3);
// Copies of the arg lists that we can iterate through.
CPURegList pcs_varargs = kPCSVarargs;
CPURegList pcs_varargs_fp = kPCSVarargsFP;
// Place the arguments. There are lots of clever tricks and optimizations we
// could use here, but Printf is a debug tool so instead we just try to keep
// it simple: Move each input that isn't already in the right place to a
// scratch register, then move everything back.
for (unsigned i = 0; i < kPrintfMaxArgCount; i++) {
// Work out the proper PCS register for this argument.
if (args[i].IsRegister()) {
pcs[i] = pcs_varargs.PopLowestIndex().X();
// We might only need a W register here. We need to know the size of the
// argument so we can properly encode it for the simulator call.
if (args[i].Is32Bits()) pcs[i] = pcs[i].W();
} else if (args[i].IsFPRegister()) {
// In C, floats are always cast to doubles for varargs calls.
pcs[i] = pcs_varargs_fp.PopLowestIndex().D();
} else {
VIXL_ASSERT(args[i].IsNone());
arg_count = i;
break;
}
// If the argument is already in the right place, leave it where it is.
if (args[i].Aliases(pcs[i])) continue;
// Otherwise, if the argument is in a PCS argument register, allocate an
// appropriate scratch register and then move it out of the way.
if (kPCSVarargs.IncludesAliasOf(args[i]) ||
kPCSVarargsFP.IncludesAliasOf(args[i])) {
if (args[i].IsRegister()) {
Register old_arg = Register(args[i]);
Register new_arg = temps.AcquireSameSizeAs(old_arg);
Mov(new_arg, old_arg);
args[i] = new_arg;
} else {
FPRegister old_arg = FPRegister(args[i]);
FPRegister new_arg = temps.AcquireSameSizeAs(old_arg);
Fmov(new_arg, old_arg);
args[i] = new_arg;
}
}
}
// Do a second pass to move values into their final positions and perform any
// conversions that may be required.
for (int i = 0; i < arg_count; i++) {
VIXL_ASSERT(pcs[i].type() == args[i].type());
if (pcs[i].IsRegister()) {
Mov(Register(pcs[i]), Register(args[i]), kDiscardForSameWReg);
} else {
VIXL_ASSERT(pcs[i].IsFPRegister());
if (pcs[i].size() == args[i].size()) {
Fmov(FPRegister(pcs[i]), FPRegister(args[i]));
} else {
Fcvt(FPRegister(pcs[i]), FPRegister(args[i]));
}
}
}
// Load the format string into x0, as per the procedure-call standard.
//
// To make the code as portable as possible, the format string is encoded
// directly in the instruction stream. It might be cleaner to encode it in a
// literal pool, but since Printf is usually used for debugging, it is
// beneficial for it to be minimally dependent on other features.
temps.Exclude(x0);
Label format_address;
Adr(x0, &format_address);
// Emit the format string directly in the instruction stream.
{
BlockLiteralPoolScope scope(this);
// Data emitted:
// branch
// strlen(format) + 1 (includes null termination)
// padding to next instruction
// unreachable
EmissionCheckScope guard(
this,
AlignUp(strlen(format) + 1, kInstructionSize) + 2 * kInstructionSize);
Label after_data;
B(&after_data);
Bind(&format_address);
EmitString(format);
Unreachable();
Bind(&after_data);
}
// We don't pass any arguments on the stack, but we still need to align the C
// stack pointer to a 16-byte boundary for PCS compliance.
if (!sp.Is(StackPointer())) {
Bic(sp, StackPointer(), 0xf);
}
// Actually call printf. This part needs special handling for the simulator,
// since the system printf function will use a different instruction set and
// the procedure-call standard will not be compatible.
#ifdef USE_SIMULATOR
{
InstructionAccurateScope scope(this, kPrintfLength / kInstructionSize);
hlt(kPrintfOpcode);
dc32(arg_count); // kPrintfArgCountOffset
// Determine the argument pattern.
uint32_t arg_pattern_list = 0;
for (int i = 0; i < arg_count; i++) {
uint32_t arg_pattern;
if (pcs[i].IsRegister()) {
arg_pattern = pcs[i].Is32Bits() ? kPrintfArgW : kPrintfArgX;
} else {
VIXL_ASSERT(pcs[i].Is64Bits());
arg_pattern = kPrintfArgD;
}
VIXL_ASSERT(arg_pattern < (1 << kPrintfArgPatternBits));
arg_pattern_list |= (arg_pattern << (kPrintfArgPatternBits * i));
}
dc32(arg_pattern_list); // kPrintfArgPatternListOffset
}
#else
Register tmp = temps.AcquireX();
Mov(tmp, reinterpret_cast<uintptr_t>(printf));
Blr(tmp);
#endif
}
void MacroAssembler::Printf(const char * format,
CPURegister arg0,
CPURegister arg1,
CPURegister arg2,
CPURegister arg3) {
// We can only print sp if it is the current stack pointer.
if (!sp.Is(StackPointer())) {
VIXL_ASSERT(!sp.Aliases(arg0));
VIXL_ASSERT(!sp.Aliases(arg1));
VIXL_ASSERT(!sp.Aliases(arg2));
VIXL_ASSERT(!sp.Aliases(arg3));
}
// Make sure that the macro assembler doesn't try to use any of our arguments
// as scratch registers.
UseScratchRegisterScope exclude_all(this);
exclude_all.ExcludeAll();
// Preserve all caller-saved registers as well as NZCV.
// If sp is the stack pointer, PushCPURegList asserts that the size of each
// list is a multiple of 16 bytes.
PushCPURegList(kCallerSaved);
PushCPURegList(kCallerSavedFP);
{ UseScratchRegisterScope temps(this);
// We can use caller-saved registers as scratch values (except for argN).
temps.Include(kCallerSaved);
temps.Include(kCallerSavedFP);
temps.Exclude(arg0, arg1, arg2, arg3);
// If any of the arguments are the current stack pointer, allocate a new
// register for them, and adjust the value to compensate for pushing the
// caller-saved registers.
bool arg0_sp = StackPointer().Aliases(arg0);
bool arg1_sp = StackPointer().Aliases(arg1);
bool arg2_sp = StackPointer().Aliases(arg2);
bool arg3_sp = StackPointer().Aliases(arg3);
if (arg0_sp || arg1_sp || arg2_sp || arg3_sp) {
// Allocate a register to hold the original stack pointer value, to pass
// to PrintfNoPreserve as an argument.
Register arg_sp = temps.AcquireX();
Add(arg_sp, StackPointer(),
kCallerSaved.TotalSizeInBytes() + kCallerSavedFP.TotalSizeInBytes());
if (arg0_sp) arg0 = Register(arg_sp.code(), arg0.size());
if (arg1_sp) arg1 = Register(arg_sp.code(), arg1.size());
if (arg2_sp) arg2 = Register(arg_sp.code(), arg2.size());
if (arg3_sp) arg3 = Register(arg_sp.code(), arg3.size());
}
// Preserve NZCV.
Register tmp = temps.AcquireX();
Mrs(tmp, NZCV);
Push(tmp, xzr);
temps.Release(tmp);
PrintfNoPreserve(format, arg0, arg1, arg2, arg3);
// Restore NZCV.
tmp = temps.AcquireX();
Pop(xzr, tmp);
Msr(NZCV, tmp);
temps.Release(tmp);
}
PopCPURegList(kCallerSavedFP);
PopCPURegList(kCallerSaved);
}
void MacroAssembler::Trace(TraceParameters parameters, TraceCommand command) {
VIXL_ASSERT(allow_macro_instructions_);
#ifdef USE_SIMULATOR
// The arguments to the trace pseudo instruction need to be contiguous in
// memory, so make sure we don't try to emit a literal pool.
InstructionAccurateScope scope(this, kTraceLength / kInstructionSize);
Label start;
bind(&start);
// Refer to instructions-a64.h for a description of the marker and its
// arguments.
hlt(kTraceOpcode);
VIXL_ASSERT(SizeOfCodeGeneratedSince(&start) == kTraceParamsOffset);
dc32(parameters);
VIXL_ASSERT(SizeOfCodeGeneratedSince(&start) == kTraceCommandOffset);
dc32(command);
#else
// Emit nothing on real hardware.
USE(parameters);
USE(command);
#endif
}
void MacroAssembler::Log(TraceParameters parameters) {
VIXL_ASSERT(allow_macro_instructions_);
#ifdef USE_SIMULATOR
// The arguments to the log pseudo instruction need to be contiguous in
// memory, so make sure we don't try to emit a literal pool.
InstructionAccurateScope scope(this, kLogLength / kInstructionSize);
Label start;
bind(&start);
// Refer to instructions-a64.h for a description of the marker and its
// arguments.
hlt(kLogOpcode);
VIXL_ASSERT(SizeOfCodeGeneratedSince(&start) == kLogParamsOffset);
dc32(parameters);
#else
// Emit nothing on real hardware.
USE(parameters);
#endif
}
void MacroAssembler::EnableInstrumentation() {
VIXL_ASSERT(!isprint(InstrumentStateEnable));
InstructionAccurateScope scope(this, 1);
movn(xzr, InstrumentStateEnable);
}
void MacroAssembler::DisableInstrumentation() {
VIXL_ASSERT(!isprint(InstrumentStateDisable));
InstructionAccurateScope scope(this, 1);
movn(xzr, InstrumentStateDisable);
}
void MacroAssembler::AnnotateInstrumentation(const char* marker_name) {
VIXL_ASSERT(strlen(marker_name) == 2);
// We allow only printable characters in the marker names. Unprintable
// characters are reserved for controlling features of the instrumentation.
VIXL_ASSERT(isprint(marker_name[0]) && isprint(marker_name[1]));
InstructionAccurateScope scope(this, 1);
movn(xzr, (marker_name[1] << 8) | marker_name[0]);
}
UseScratchRegisterScope::~UseScratchRegisterScope() {
available_->set_list(old_available_);
availablefp_->set_list(old_availablefp_);
}
bool UseScratchRegisterScope::IsAvailable(const CPURegister& reg) const {
return available_->IncludesAliasOf(reg) || availablefp_->IncludesAliasOf(reg);
}
Register UseScratchRegisterScope::AcquireSameSizeAs(const Register& reg) {
int code = AcquireNextAvailable(available_).code();
return Register(code, reg.size());
}
FPRegister UseScratchRegisterScope::AcquireSameSizeAs(const FPRegister& reg) {
int code = AcquireNextAvailable(availablefp_).code();
return FPRegister(code, reg.size());
}
void UseScratchRegisterScope::Release(const CPURegister& reg) {
if (reg.IsRegister()) {
ReleaseByCode(available_, reg.code());
} else if (reg.IsFPRegister()) {
ReleaseByCode(availablefp_, reg.code());
} else {
VIXL_ASSERT(reg.IsNone());
}
}
void UseScratchRegisterScope::Include(const CPURegList& list) {
if (list.type() == CPURegister::kRegister) {
// Make sure that neither sp nor xzr are included the list.
IncludeByRegList(available_, list.list() & ~(xzr.Bit() | sp.Bit()));
} else {
VIXL_ASSERT(list.type() == CPURegister::kFPRegister);
IncludeByRegList(availablefp_, list.list());
}
}
void UseScratchRegisterScope::Include(const Register& reg1,
const Register& reg2,
const Register& reg3,
const Register& reg4) {
RegList include = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit();
// Make sure that neither sp nor xzr are included the list.
include &= ~(xzr.Bit() | sp.Bit());
IncludeByRegList(available_, include);
}
void UseScratchRegisterScope::Include(const FPRegister& reg1,
const FPRegister& reg2,
const FPRegister& reg3,
const FPRegister& reg4) {
RegList include = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit();
IncludeByRegList(availablefp_, include);
}
void UseScratchRegisterScope::Exclude(const CPURegList& list) {
if (list.type() == CPURegister::kRegister) {
ExcludeByRegList(available_, list.list());
} else {
VIXL_ASSERT(list.type() == CPURegister::kFPRegister);
ExcludeByRegList(availablefp_, list.list());
}
}
void UseScratchRegisterScope::Exclude(const Register& reg1,
const Register& reg2,
const Register& reg3,
const Register& reg4) {
RegList exclude = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit();
ExcludeByRegList(available_, exclude);
}
void UseScratchRegisterScope::Exclude(const FPRegister& reg1,
const FPRegister& reg2,
const FPRegister& reg3,
const FPRegister& reg4) {
RegList excludefp = reg1.Bit() | reg2.Bit() | reg3.Bit() | reg4.Bit();
ExcludeByRegList(availablefp_, excludefp);
}
void UseScratchRegisterScope::Exclude(const CPURegister& reg1,
const CPURegister& reg2,
const CPURegister& reg3,
const CPURegister& reg4) {
RegList exclude = 0;
RegList excludefp = 0;
const CPURegister regs[] = {reg1, reg2, reg3, reg4};
for (unsigned i = 0; i < (sizeof(regs) / sizeof(regs[0])); i++) {
if (regs[i].IsRegister()) {
exclude |= regs[i].Bit();
} else if (regs[i].IsFPRegister()) {
excludefp |= regs[i].Bit();
} else {
VIXL_ASSERT(regs[i].IsNone());
}
}
ExcludeByRegList(available_, exclude);
ExcludeByRegList(availablefp_, excludefp);
}
void UseScratchRegisterScope::ExcludeAll() {
ExcludeByRegList(available_, available_->list());
ExcludeByRegList(availablefp_, availablefp_->list());
}
CPURegister UseScratchRegisterScope::AcquireNextAvailable(
CPURegList* available) {
VIXL_CHECK(!available->IsEmpty());
CPURegister result = available->PopLowestIndex();
VIXL_ASSERT(!AreAliased(result, xzr, sp));
return result;
}
void UseScratchRegisterScope::ReleaseByCode(CPURegList* available, int code) {
ReleaseByRegList(available, static_cast<RegList>(1) << code);
}
void UseScratchRegisterScope::ReleaseByRegList(CPURegList* available,
RegList regs) {
available->set_list(available->list() | regs);
}
void UseScratchRegisterScope::IncludeByRegList(CPURegList* available,
RegList regs) {
available->set_list(available->list() | regs);
}
void UseScratchRegisterScope::ExcludeByRegList(CPURegList* available,
RegList exclude) {
available->set_list(available->list() & ~exclude);
}
} // namespace vixl