package asm
//go:generate stringer -output jump_string.go -type=JumpOp
// JumpOp affect control flow.
//
// msb lsb
// +----+-+---+
// |OP |s|cls|
// +----+-+---+
type JumpOp uint8
const jumpMask OpCode = aluMask
const (
// InvalidJumpOp is returned by getters when invoked
// on non branch OpCodes
InvalidJumpOp JumpOp = 0xff
// Ja jumps by offset unconditionally
Ja JumpOp = 0x00
// JEq jumps by offset if r == imm
JEq JumpOp = 0x10
// JGT jumps by offset if r > imm
JGT JumpOp = 0x20
// JGE jumps by offset if r >= imm
JGE JumpOp = 0x30
// JSet jumps by offset if r & imm
JSet JumpOp = 0x40
// JNE jumps by offset if r != imm
JNE JumpOp = 0x50
// JSGT jumps by offset if signed r > signed imm
JSGT JumpOp = 0x60
// JSGE jumps by offset if signed r >= signed imm
JSGE JumpOp = 0x70
// Call builtin or user defined function from imm
Call JumpOp = 0x80
// Exit ends execution, with value in r0
Exit JumpOp = 0x90
// JLT jumps by offset if r < imm
JLT JumpOp = 0xa0
// JLE jumps by offset if r <= imm
JLE JumpOp = 0xb0
// JSLT jumps by offset if signed r < signed imm
JSLT JumpOp = 0xc0
// JSLE jumps by offset if signed r <= signed imm
JSLE JumpOp = 0xd0
)
// Return emits an exit instruction.
//
// Requires a return value in R0.
func Return() Instruction {
return Instruction{
OpCode: OpCode(JumpClass).SetJumpOp(Exit),
}
}
// Op returns the OpCode for a given jump source.
func (op JumpOp) Op(source Source) OpCode {
return OpCode(JumpClass).SetJumpOp(op).SetSource(source)
}
// Imm compares 64 bit dst to 64 bit value (sign extended), and adjusts PC by offset if the condition is fulfilled.
func (op JumpOp) Imm(dst Register, value int32, label string) Instruction {
return Instruction{
OpCode: op.opCode(JumpClass, ImmSource),
Dst: dst,
Offset: -1,
Constant: int64(value),
}.WithReference(label)
}
// Imm32 compares 32 bit dst to 32 bit value, and adjusts PC by offset if the condition is fulfilled.
// Requires kernel 5.1.
func (op JumpOp) Imm32(dst Register, value int32, label string) Instruction {
return Instruction{
OpCode: op.opCode(Jump32Class, ImmSource),
Dst: dst,
Offset: -1,
Constant: int64(value),
}.WithReference(label)
}
// Reg compares 64 bit dst to 64 bit src, and adjusts PC by offset if the condition is fulfilled.
func (op JumpOp) Reg(dst, src Register, label string) Instruction {
return Instruction{
OpCode: op.opCode(JumpClass, RegSource),
Dst: dst,
Src: src,
Offset: -1,
}.WithReference(label)
}
// Reg32 compares 32 bit dst to 32 bit src, and adjusts PC by offset if the condition is fulfilled.
// Requires kernel 5.1.
func (op JumpOp) Reg32(dst, src Register, label string) Instruction {
return Instruction{
OpCode: op.opCode(Jump32Class, RegSource),
Dst: dst,
Src: src,
Offset: -1,
}.WithReference(label)
}
func (op JumpOp) opCode(class Class, source Source) OpCode {
if op == Exit || op == Call || op == Ja {
return InvalidOpCode
}
return OpCode(class).SetJumpOp(op).SetSource(source)
}
// Label adjusts PC to the address of the label.
func (op JumpOp) Label(label string) Instruction {
if op == Call {
return Instruction{
OpCode: OpCode(JumpClass).SetJumpOp(Call),
Src: PseudoCall,
Constant: -1,
}.WithReference(label)
}
return Instruction{
OpCode: OpCode(JumpClass).SetJumpOp(op),
Offset: -1,
}.WithReference(label)
}