func (mach X86) OpBranchIf(code gen.Coder, x values.Operand, yes bool, addr int32) (sites []int32) {
var cond values.Condition
if x.Storage == values.ConditionFlags {
cond = x.Condition()
} else {
reg, _, own := mach.opBorrowMaybeScratchReg(code, x, false)
if own {
defer code.FreeReg(types.I32, reg)
}
Test.opFromReg(code, types.I32, reg, reg)
cond = values.Ne
}
if !yes {
cond = values.InvertedConditions[cond]
}
var end links.L
switch {
case cond >= values.MinUnorderedOrCondition:
Jp.op(code, addr)
sites = append(sites, code.Len())
case cond >= values.MinOrderedAndCondition:
Jp.rel8.opStub(code)
end.AddSite(code.Len())
}
conditionInsns[cond].jcc.op(code, addr)
sites = append(sites, code.Len())
end.Addr = code.Len()
mach.updateBranches8(code, &end)
return
}
func (mach X86) OpSelect(code gen.RegCoder, a, b, condOperand values.Operand) values.Operand {
defer code.Consumed(condOperand)
var cond values.Condition
switch condOperand.Storage {
case values.VarMem:
Cmp.opImmToStack(code, types.I32, condOperand.VarMemOffset(), 0)
cond = values.Ne
case values.VarReg, values.TempReg:
reg := condOperand.Reg()
Test.opFromReg(code, types.I32, reg, reg)
cond = values.Ne
case values.Stack:
mach.OpAddImmToStackPtr(code, 8) // do before cmp to avoid overwriting flags
Cmp.opImmToStack(code, types.I32, -8, 0)
cond = values.Ne
case values.ConditionFlags:
cond = condOperand.Condition()
case values.Imm:
if condOperand.ImmValue() != 0 {
code.Consumed(b)
return a
} else {
code.Consumed(a)
return b
}
default:
panic(condOperand)
}
t := a.Type
targetReg, _ := mach.opMaybeResultReg(code, b, true)
switch t.Category() {
case types.Int:
cmov := conditionInsns[cond].cmov
switch a.Storage {
case values.VarMem:
cmov.opFromStack(code, t, targetReg, a.VarMemOffset())
default:
aReg, _, own := mach.opBorrowMaybeScratchReg(code, a, true)
if own {
defer code.FreeReg(t, aReg)
}
cmov.opFromReg(code, t, targetReg, aReg)
}
case types.Float:
var moveIt links.L
var end links.L
cond = values.InvertedConditions[cond]
notCondJump := conditionInsns[cond].jcc
switch {
case cond >= values.MinUnorderedOrCondition:
Jp.rel8.opStub(code) // move it if unordered
moveIt.AddSite(code.Len())
notCondJump.rel8.opStub(code) // break if not cond
end.AddSite(code.Len())
case cond >= values.MinOrderedAndCondition:
Jp.rel8.opStub(code) // break if unordered
end.AddSite(code.Len())
notCondJump.rel8.opStub(code) // break if not cond
end.AddSite(code.Len())
default:
notCondJump.rel8.opStub(code) // break if not cond
end.AddSite(code.Len())
}
moveIt.Addr = code.Len()
mach.updateBranches8(code, &moveIt)
mach.OpMove(code, targetReg, a, false)
end.Addr = code.Len()
mach.updateBranches8(code, &end)
default:
panic(t)
}
// cmov zero-extends the target unconditionally
return values.TempRegOperand(t, targetReg, true)
}
// OpMove must not update CPU's condition flags if preserveFlags is set.
//
// X86 implementation note: must not blindly rely on regScratch or regResult in
// this function because we may be moving to one of them.
func (mach X86) OpMove(code gen.Coder, targetReg regs.R, x values.Operand, preserveFlags bool) (zeroExt bool) {
switch x.Type.Category() {
case types.Int:
switch x.Storage {
case values.Imm:
if value := x.ImmValue(); value == 0 && !preserveFlags {
Xor.opFromReg(code, types.I32, targetReg, targetReg)
} else {
MovImm64.op(code, x.Type, targetReg, value)
}
zeroExt = true
case values.VarMem:
Mov.opFromStack(code, x.Type, targetReg, x.VarMemOffset())
zeroExt = true
case values.VarReg:
if sourceReg := x.Reg(); sourceReg != targetReg {
Mov.opFromReg(code, x.Type, targetReg, sourceReg)
zeroExt = true
}
case values.TempReg:
if sourceReg := x.Reg(); sourceReg != targetReg {
Mov.opFromReg(code, x.Type, targetReg, sourceReg)
zeroExt = true
} else if targetReg == regResult {
zeroExt = x.RegZeroExt()
} else {
panic("moving temporary integer register to itself")
}
case values.Stack:
Pop.op(code, targetReg)
case values.ConditionFlags:
if x.Type != types.I32 {
panic(x)
}
var end links.L
cond := x.Condition()
setcc := conditionInsns[cond].setcc
switch {
case cond >= values.MinUnorderedOrCondition:
MovImm.opImm(code, x.Type, targetReg, 1) // true
Jp.rel8.opStub(code) // if unordered, else
end.AddSite(code.Len()) //
setcc.opReg(code, targetReg) // cond
case cond >= values.MinOrderedAndCondition:
MovImm.opImm(code, x.Type, targetReg, 0) // false
Jp.rel8.opStub(code) // if unordered, else
end.AddSite(code.Len()) //
setcc.opReg(code, targetReg) // cond
default:
setcc.opReg(code, targetReg)
Movzx8.opFromReg(code, x.Type, targetReg, targetReg)
}
end.Addr = code.Len()
mach.updateBranches8(code, &end)
zeroExt = true
default:
panic(x)
}
case types.Float:
switch x.Storage {
case values.Imm:
if value := x.ImmValue(); value == 0 {
PxorSSE.opFromReg(code, x.Type, targetReg, targetReg)
} else {
MovImm64.op(code, x.Type, regScratch, value) // integer scratch register
MovSSE.opFromReg(code, x.Type, targetReg, regScratch)
}
case values.VarMem:
MovsSSE.opFromStack(code, x.Type, targetReg, x.VarMemOffset())
case values.VarReg:
if sourceReg := x.Reg(); sourceReg != targetReg {
MovsSSE.opFromReg(code, x.Type, targetReg, sourceReg)
}
case values.TempReg:
if sourceReg := x.Reg(); sourceReg != targetReg {
MovsSSE.opFromReg(code, x.Type, targetReg, sourceReg)
} else if targetReg != regResult {
panic("moving temporary float register to itself")
}
case values.Stack:
popFloatOp(code, x.Type, targetReg)
default:
panic(x)
}
default:
panic(x)
}
code.Consumed(x)
return
}