// TODO verify that the arguments are being compared in the right order
// cmpq offset(%reg), $imm
inline void _emitAttrCmpImm(int reg, int offset, int64_t val) {
assert((-1L<<31) <= val && val < (1L<<31)-1);
int rex = X86::REX_W;
if (reg >= 8) {
rex |= X86::REX_B;
reg -= 8;
}
assert(reg >= 0 && reg < 8);
_emitRex(rex);
_emitByte(0x81);
assert(-0x80 <= offset && offset < 0x80);
if (offset == 0) {
_emitModRM(0b00, 7, reg);
} else {
_emitModRM(0b01, 7, reg);
_emitByte(offset);
}
for (int i = 0; i < 4; i++) {
_emitByte(val & 0xff);
val >>= 8;
}
}
inline void _emitCmpDisplacement(uint8_t reg1, uint64_t reg2, int displacement) {
// TODO if it's bigger, we could use a larger scale since
// things are most likely aligned
assert(displacement >= -0x80 && displacement < 0x80);
uint8_t flags = 0;
flags |= X86::REX_W;
if (reg1 >= 8) {
flags |= X86::REX_R;
reg1 &= 0b111;
}
if (reg2 >= 8) {
flags |= X86::REX_B;
reg2 &= 0b111;
}
_emitRex(flags);
_emitByte(0x39);
if (displacement == 0) {
// Since we're emitting into a fixed-size section I guess there might not be
// too much benifit to the more compact encoding, but it makes me feel better:
_emitModRM(0b00, reg1, reg2);
} else {
_emitModRM(0b01, reg1, reg2);
_emitByte(displacement);
}
}
// movzbq %src_reg, %dest_reg
void _emitZeroExtend(int src_reg, int dest_reg) {
assert(0 <= src_reg && src_reg < 8);
assert(0 <= dest_reg && dest_reg < 8);
_emitRex(X86::REX_W);
_emitByte(0x0f);
_emitByte(0xb6);
_emitModRM(0b11, dest_reg, src_reg);
}
inline void _emitMoveImm64(uint8_t reg, uint64_t value) {
assert(reg >= 0 && reg < 8);
_emitRex(X86::REX_W);
_emitByte(0xb8 + reg);
for (int i = 0; i < 8; i++) {
_emitByte(value & 0xff);
value >>= 8;
}
}
void _emitCondSet(int dest_reg, int cond_code) {
assert(0 <= dest_reg && dest_reg < 8);
assert(0 <= cond_code && cond_code < 16);
if (dest_reg >= 4)
_emitRex(0);
_emitByte(0x0f);
_emitByte(0x90 + cond_code);
_emitModRM(0b11, 0, dest_reg);
}
// incq offset(%reg)
virtual void _emitIncattr(int reg, int offset) {
assert(offset >= -0x80 && offset < 0x80);
int rex = X86::REX_W;
if (reg >= 8) {
rex |= X86::REX_B;
reg -= 8;
}
_emitRex(rex);
_emitByte(0xff);
_emitModRM(0b01, 0b000, reg);
_emitByte(offset);
}
void _emitJmp(void* dest_addr) {
long offset = (uint8_t*)dest_addr - addr - 2;
if (offset >= -0x80 && offset < 0x80) {
_emitByte(0xeb);
_emitByte(offset);
} else {
assert(offset >= -1L<<31 && offset < 1L<<31);
offset -= 3;
_emitByte(0xe9);
for (int i = 0; i < 4; i++) {
_emitByte(offset & 0xff);
offset >>= 8;
}
}
}
// test[q] %reg1, %reg2
inline void _emitTest(int reg1, int reg2) {
assert(reg1 >= 0 && reg1 < 8);
assert(reg2 >= 0 && reg2 < 8);
_emitRex(X86::REX_W);
_emitByte(0x85);
_emitModRM(0b11, reg1, reg2);
}
/// "op $val, %reg"
inline void _emitArith(int reg, int val, int opcode) {
assert(val >= -0x80 && val < 0x80);
assert(opcode < 8);
uint8_t flags = 0;
flags |= X86::REX_W;
if (reg >= 8) {
flags |= X86::REX_B;
reg &= 0b111;
}
_emitRex(flags);
_emitByte(0x83);
_emitModRM(0b11, opcode, reg);
_emitByte(val);
}
inline void _emitJne(uint8_t* dest_addr, bool unlikely) {
_emitJmpCond(dest_addr, X86::COND_NOT_EQUAL, unlikely);
int offset = dest_addr - addr - 2;
if (unlikely)
offset -= 1;
if (offset >= -0x80 && offset < 0x80) {
if (unlikely)
_emitByte(0x2e);
_emitByte(0x75);
_emitByte(offset);
} else {
offset -= 4;
if (unlikely)
_emitByte(0x2e);
_emitByte(0x0f);
_emitByte(0x85);
for (int i = 0; i < 4; i++) {
_emitByte(offset & 0xff);
offset >>= 8;
}
}
}
// TODO verify that the arguments are being compared in the right order
// cmp $val, %reg
inline void _emitCmpImm(int reg, int64_t val) {
assert((-1L<<31) <= val && val < (1L<<31)-1);
int rex = X86::REX_W;
if (reg > 8) {
rex |= X86::REX_B;
reg -= 8;
}
assert(0 <= reg && reg < 8);
_emitRex(rex);
_emitByte(0x81);
_emitModRM(0b11, 7, reg);
for (int i = 0; i < 4; i++) {
_emitByte(val & 0xff);
val >>= 8;
}
}
inline void _emitPop(uint8_t reg) {
assert(reg != X86::REG_STACK_POINTER); // this might work but most likely a bug
assert(0 <= reg && reg < 16);
if (reg >= 8) {
_emitRex(X86::REX_B);
reg -= 8;
}
assert(reg < 8);
_emitByte(0x58 + reg);
}
// TODO verify that the arguments are being compared in the right order
// cmpq offset(%reg1), %reg2
inline void _emitAttrCmp(int reg1, int reg1_offset, int reg2) {
int rex = X86::REX_W;
if (reg1 >= 8) {
rex |= X86::REX_B;
reg1 -= 8;
}
assert(reg1 >= 0 && reg1 < 8);
assert(reg2 >= 0 && reg2 < 8);
_emitRex(rex);
_emitByte(0x3B);
assert(-0x80 <= reg1_offset && reg1_offset < 0x80);
if (reg1_offset == 0) {
_emitModRM(0b00, reg2, reg1);
} else {
_emitModRM(0b01, reg2, reg1);
_emitByte(reg1_offset);
}
}
/// mov $displacement(%source) %dest
inline void _emitLoadRegIndirect(int source, int displacement, int dest) {
bool usesib = false;
if (source == 0b100 || dest == 0b1100) {
usesib = true;
}
uint8_t flags = X86::REX_W;
if (dest >= 8) {
flags |= X86::REX_R;
dest &= 0b111;
}
if (source >= 8) {
flags |= X86::REX_B;
source &= 0b111;
}
_emitRex(flags);
_emitByte(0x8b);
int mode;
if (displacement == 0)
mode = 0b00;
else if (-0x80 <= displacement && displacement < 0x79)
mode = 0b01;
else
mode = 0b10;
_emitModRM(mode, dest, source);
if (usesib)
_emitSIB(0b00, 0b100, source);
if (mode == 0b01) {
_emitByte(displacement);
} else if (mode == 0b10) {
for (int i = 0; i < 4; i++) {
_emitByte(displacement & 0xff);
displacement >>= 8;
}
}
}
// TODO verify that the arguments are being compared in the right order
// cmpq %reg1, %reg2 # or maybe they're reversed?
inline void _emitCmp(int reg1, int reg2) {
int rex = X86::REX_W;
if (reg1 >= 8) {
rex |= X86::REX_R;
reg1 -= 8;
}
assert(reg1 >= 0 && reg1 < 8);
assert(reg2 >= 0 && reg2 < 8);
_emitRex(rex);
_emitByte(0x39);
_emitModRM(0b11, reg1, reg2);
}
inline void _emitMoveReg(int source, int dest) {
uint8_t flags = 0;
flags |= X86::REX_W;
if (dest >= 8) {
flags |= X86::REX_B;
dest &= 0b111;
}
if (source >= 8) {
flags |= X86::REX_R;
source &= 0b111;
}
_emitRex(flags);
_emitByte(0x89);
_emitModRM(0b11, source, dest);
}
inline void _emitJmpCond(uint8_t* dest_addr, X86::ConditionCode condition, bool unlikely) {
int offset = dest_addr - addr - 2;
if (unlikely) offset -= 1;
if (offset >= -0x80 && offset < 0x80) {
if (unlikely)
_emitByte(0x2e);
_emitByte(0x75);
_emitByte(offset);
} else {
offset -= 4;
if (unlikely)
_emitByte(0x2e);
_emitByte(0x0f);
_emitByte(0x80 | condition);
for (int i = 0; i < 4; i++) {
_emitByte(offset & 0xff);
offset >>= 8;
}
}
}
inline void _emitRex(uint8_t flags) {
assert(0 <= flags && flags < 16);
_emitByte(0x40 | flags);
}
inline void _emitModRM(uint8_t mod, uint8_t reg, uint8_t rm) {
assert(mod < 4);
assert(reg < 8);
assert(rm < 8);
_emitByte((mod << 6) | (reg << 3) | rm);
}
inline void _emitSIB(uint8_t scalebits, uint8_t index, uint8_t base) {
assert(scalebits < 4);
assert(index < 8);
assert(base < 8);
_emitByte((scalebits << 6) | (index << 3) | base);
}