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// Copyright 2011 the V8 project authors. 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 Google Inc. 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 AND 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 "v8.h"
#if defined(V8_TARGET_ARCH_IA32)
#include "codegen.h"
namespace v8 {
namespace internal {
// -------------------------------------------------------------------------
// Platform-specific RuntimeCallHelper functions.
void StubRuntimeCallHelper::BeforeCall(MacroAssembler* masm) const {
masm->EnterInternalFrame();
}
void StubRuntimeCallHelper::AfterCall(MacroAssembler* masm) const {
masm->LeaveInternalFrame();
}
#define __ masm.
static void MemCopyWrapper(void* dest, const void* src, size_t size) {
memcpy(dest, src, size);
}
OS::MemCopyFunction CreateMemCopyFunction() {
size_t actual_size;
// Allocate buffer in executable space.
byte* buffer = static_cast<byte*>(OS::Allocate(1 * KB,
&actual_size,
true));
if (buffer == NULL) return &MemCopyWrapper;
MacroAssembler masm(NULL, buffer, static_cast<int>(actual_size));
// Generated code is put into a fixed, unmovable, buffer, and not into
// the V8 heap. We can't, and don't, refer to any relocatable addresses
// (e.g. the JavaScript nan-object).
// 32-bit C declaration function calls pass arguments on stack.
// Stack layout:
// esp[12]: Third argument, size.
// esp[8]: Second argument, source pointer.
// esp[4]: First argument, destination pointer.
// esp[0]: return address
const int kDestinationOffset = 1 * kPointerSize;
const int kSourceOffset = 2 * kPointerSize;
const int kSizeOffset = 3 * kPointerSize;
int stack_offset = 0; // Update if we change the stack height.
if (FLAG_debug_code) {
__ cmp(Operand(esp, kSizeOffset + stack_offset),
Immediate(OS::kMinComplexMemCopy));
Label ok;
__ j(greater_equal, &ok);
__ int3();
__ bind(&ok);
}
if (CpuFeatures::IsSupported(SSE2)) {
CpuFeatures::Scope enable(SSE2);
__ push(edi);
__ push(esi);
stack_offset += 2 * kPointerSize;
Register dst = edi;
Register src = esi;
Register count = ecx;
__ mov(dst, Operand(esp, stack_offset + kDestinationOffset));
__ mov(src, Operand(esp, stack_offset + kSourceOffset));
__ mov(count, Operand(esp, stack_offset + kSizeOffset));
__ movdqu(xmm0, Operand(src, 0));
__ movdqu(Operand(dst, 0), xmm0);
__ mov(edx, dst);
__ and_(edx, 0xF);
__ neg(edx);
__ add(Operand(edx), Immediate(16));
__ add(dst, Operand(edx));
__ add(src, Operand(edx));
__ sub(Operand(count), edx);
// edi is now aligned. Check if esi is also aligned.
Label unaligned_source;
__ test(Operand(src), Immediate(0x0F));
__ j(not_zero, &unaligned_source);
{
// Copy loop for aligned source and destination.
__ mov(edx, count);
Register loop_count = ecx;
Register count = edx;
__ shr(loop_count, 5);
{
// Main copy loop.
Label loop;
__ bind(&loop);
__ prefetch(Operand(src, 0x20), 1);
__ movdqa(xmm0, Operand(src, 0x00));
__ movdqa(xmm1, Operand(src, 0x10));
__ add(Operand(src), Immediate(0x20));
__ movdqa(Operand(dst, 0x00), xmm0);
__ movdqa(Operand(dst, 0x10), xmm1);
__ add(Operand(dst), Immediate(0x20));
__ dec(loop_count);
__ j(not_zero, &loop);
}
// At most 31 bytes to copy.
Label move_less_16;
__ test(Operand(count), Immediate(0x10));
__ j(zero, &move_less_16);
__ movdqa(xmm0, Operand(src, 0));
__ add(Operand(src), Immediate(0x10));
__ movdqa(Operand(dst, 0), xmm0);
__ add(Operand(dst), Immediate(0x10));
__ bind(&move_less_16);
// At most 15 bytes to copy. Copy 16 bytes at end of string.
__ and_(count, 0xF);
__ movdqu(xmm0, Operand(src, count, times_1, -0x10));
__ movdqu(Operand(dst, count, times_1, -0x10), xmm0);
__ mov(eax, Operand(esp, stack_offset + kDestinationOffset));
__ pop(esi);
__ pop(edi);
__ ret(0);
}
__ Align(16);
{
// Copy loop for unaligned source and aligned destination.
// If source is not aligned, we can't read it as efficiently.
__ bind(&unaligned_source);
__ mov(edx, ecx);
Register loop_count = ecx;
Register count = edx;
__ shr(loop_count, 5);
{
// Main copy loop
Label loop;
__ bind(&loop);
__ prefetch(Operand(src, 0x20), 1);
__ movdqu(xmm0, Operand(src, 0x00));
__ movdqu(xmm1, Operand(src, 0x10));
__ add(Operand(src), Immediate(0x20));
__ movdqa(Operand(dst, 0x00), xmm0);
__ movdqa(Operand(dst, 0x10), xmm1);
__ add(Operand(dst), Immediate(0x20));
__ dec(loop_count);
__ j(not_zero, &loop);
}
// At most 31 bytes to copy.
Label move_less_16;
__ test(Operand(count), Immediate(0x10));
__ j(zero, &move_less_16);
__ movdqu(xmm0, Operand(src, 0));
__ add(Operand(src), Immediate(0x10));
__ movdqa(Operand(dst, 0), xmm0);
__ add(Operand(dst), Immediate(0x10));
__ bind(&move_less_16);
// At most 15 bytes to copy. Copy 16 bytes at end of string.
__ and_(count, 0x0F);
__ movdqu(xmm0, Operand(src, count, times_1, -0x10));
__ movdqu(Operand(dst, count, times_1, -0x10), xmm0);
__ mov(eax, Operand(esp, stack_offset + kDestinationOffset));
__ pop(esi);
__ pop(edi);
__ ret(0);
}
} else {
// SSE2 not supported. Unlikely to happen in practice.
__ push(edi);
__ push(esi);
stack_offset += 2 * kPointerSize;
__ cld();
Register dst = edi;
Register src = esi;
Register count = ecx;
__ mov(dst, Operand(esp, stack_offset + kDestinationOffset));
__ mov(src, Operand(esp, stack_offset + kSourceOffset));
__ mov(count, Operand(esp, stack_offset + kSizeOffset));
// Copy the first word.
__ mov(eax, Operand(src, 0));
__ mov(Operand(dst, 0), eax);
// Increment src,dstso that dst is aligned.
__ mov(edx, dst);
__ and_(edx, 0x03);
__ neg(edx);
__ add(Operand(edx), Immediate(4)); // edx = 4 - (dst & 3)
__ add(dst, Operand(edx));
__ add(src, Operand(edx));
__ sub(Operand(count), edx);
// edi is now aligned, ecx holds number of remaning bytes to copy.
__ mov(edx, count);
count = edx;
__ shr(ecx, 2); // Make word count instead of byte count.
__ rep_movs();
// At most 3 bytes left to copy. Copy 4 bytes at end of string.
__ and_(count, 3);
__ mov(eax, Operand(src, count, times_1, -4));
__ mov(Operand(dst, count, times_1, -4), eax);
__ mov(eax, Operand(esp, stack_offset + kDestinationOffset));
__ pop(esi);
__ pop(edi);
__ ret(0);
}
CodeDesc desc;
masm.GetCode(&desc);
ASSERT(desc.reloc_size == 0);
CPU::FlushICache(buffer, actual_size);
OS::ProtectCode(buffer, actual_size);
return FUNCTION_CAST<OS::MemCopyFunction>(buffer);
}
#undef __
} } // namespace v8::internal
#endif // V8_TARGET_ARCH_IA32
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