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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "context_x86.h"
#include "mirror/art_method.h"
#include "mirror/object-inl.h"
#include "stack.h"
namespace art {
namespace x86 {
static const uintptr_t gZero = 0;
void X86Context::Reset() {
for (size_t i = 0; i < kNumberOfCpuRegisters; i++) {
gprs_[i] = NULL;
}
gprs_[ESP] = &esp_;
// Initialize registers with easy to spot debug values.
esp_ = X86Context::kBadGprBase + ESP;
eip_ = X86Context::kBadGprBase + kNumberOfCpuRegisters;
}
void X86Context::FillCalleeSaves(const StackVisitor& fr) {
mirror::ArtMethod* method = fr.GetMethod();
uint32_t core_spills = method->GetCoreSpillMask();
size_t spill_count = POPCOUNT(core_spills);
DCHECK_EQ(method->GetFpSpillMask(), 0u);
size_t frame_size = method->GetFrameSizeInBytes();
if (spill_count > 0) {
// Lowest number spill is farthest away, walk registers and fill into context.
int j = 2; // Offset j to skip return address spill.
for (int i = 0; i < kNumberOfCpuRegisters; i++) {
if (((core_spills >> i) & 1) != 0) {
gprs_[i] = fr.CalleeSaveAddress(spill_count - j, frame_size);
j++;
}
}
}
}
void X86Context::SmashCallerSaves() {
// This needs to be 0 because we want a null/zero return value.
gprs_[EAX] = const_cast<uintptr_t*>(&gZero);
gprs_[EDX] = const_cast<uintptr_t*>(&gZero);
gprs_[ECX] = NULL;
gprs_[EBX] = NULL;
}
void X86Context::SetGPR(uint32_t reg, uintptr_t value) {
CHECK_LT(reg, static_cast<uint32_t>(kNumberOfCpuRegisters));
CHECK_NE(gprs_[reg], &gZero);
CHECK(gprs_[reg] != NULL);
*gprs_[reg] = value;
}
void X86Context::DoLongJump() {
#if defined(__i386__)
// Array of GPR values, filled from the context backward for the long jump pop. We add a slot at
// the top for the stack pointer that doesn't get popped in a pop-all.
volatile uintptr_t gprs[kNumberOfCpuRegisters + 1];
for (size_t i = 0; i < kNumberOfCpuRegisters; ++i) {
gprs[kNumberOfCpuRegisters - i - 1] = gprs_[i] != NULL ? *gprs_[i] : X86Context::kBadGprBase + i;
}
// We want to load the stack pointer one slot below so that the ret will pop eip.
uintptr_t esp = gprs[kNumberOfCpuRegisters - ESP - 1] - kWordSize;
gprs[kNumberOfCpuRegisters] = esp;
*(reinterpret_cast<uintptr_t*>(esp)) = eip_;
__asm__ __volatile__(
"movl %0, %%esp\n\t" // ESP points to gprs.
"popal\n\t" // Load all registers except ESP and EIP with values in gprs.
"popl %%esp\n\t" // Load stack pointer.
"ret\n\t" // From higher in the stack pop eip.
: // output.
: "g"(&gprs[0]) // input.
:); // clobber.
#else
UNIMPLEMENTED(FATAL);
#endif
}
} // namespace x86
} // namespace art
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