// Copyright 2016 The Go Authors. All rights reserved.
|
// Use of this source code is governed by a BSD-style
|
// license that can be found in the LICENSE file.
|
|
package x86
|
|
import (
|
"cmd/compile/internal/gc"
|
"cmd/compile/internal/ssa"
|
"cmd/compile/internal/types"
|
"cmd/internal/obj"
|
"cmd/internal/obj/x86"
|
"math"
|
)
|
|
// Generates code for v using 387 instructions.
|
func ssaGenValue387(s *gc.SSAGenState, v *ssa.Value) {
|
// The SSA compiler pretends that it has an SSE backend.
|
// If we don't have one of those, we need to translate
|
// all the SSE ops to equivalent 387 ops. That's what this
|
// function does.
|
|
switch v.Op {
|
case ssa.Op386MOVSSconst, ssa.Op386MOVSDconst:
|
iv := uint64(v.AuxInt)
|
if iv == 0x0000000000000000 { // +0.0
|
s.Prog(x86.AFLDZ)
|
} else if iv == 0x3ff0000000000000 { // +1.0
|
s.Prog(x86.AFLD1)
|
} else if iv == 0x8000000000000000 { // -0.0
|
s.Prog(x86.AFLDZ)
|
s.Prog(x86.AFCHS)
|
} else if iv == 0xbff0000000000000 { // -1.0
|
s.Prog(x86.AFLD1)
|
s.Prog(x86.AFCHS)
|
} else if iv == 0x400921fb54442d18 { // +pi
|
s.Prog(x86.AFLDPI)
|
} else if iv == 0xc00921fb54442d18 { // -pi
|
s.Prog(x86.AFLDPI)
|
s.Prog(x86.AFCHS)
|
} else { // others
|
p := s.Prog(loadPush(v.Type))
|
p.From.Type = obj.TYPE_FCONST
|
p.From.Val = math.Float64frombits(iv)
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
}
|
popAndSave(s, v)
|
|
case ssa.Op386MOVSSconst2, ssa.Op386MOVSDconst2:
|
p := s.Prog(loadPush(v.Type))
|
p.From.Type = obj.TYPE_MEM
|
p.From.Reg = v.Args[0].Reg()
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
popAndSave(s, v)
|
|
case ssa.Op386MOVSSload, ssa.Op386MOVSDload, ssa.Op386MOVSSloadidx1, ssa.Op386MOVSDloadidx1, ssa.Op386MOVSSloadidx4, ssa.Op386MOVSDloadidx8:
|
p := s.Prog(loadPush(v.Type))
|
p.From.Type = obj.TYPE_MEM
|
p.From.Reg = v.Args[0].Reg()
|
gc.AddAux(&p.From, v)
|
switch v.Op {
|
case ssa.Op386MOVSSloadidx1, ssa.Op386MOVSDloadidx1:
|
p.From.Scale = 1
|
p.From.Index = v.Args[1].Reg()
|
if p.From.Index == x86.REG_SP {
|
p.From.Reg, p.From.Index = p.From.Index, p.From.Reg
|
}
|
case ssa.Op386MOVSSloadidx4:
|
p.From.Scale = 4
|
p.From.Index = v.Args[1].Reg()
|
case ssa.Op386MOVSDloadidx8:
|
p.From.Scale = 8
|
p.From.Index = v.Args[1].Reg()
|
}
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
popAndSave(s, v)
|
|
case ssa.Op386MOVSSstore, ssa.Op386MOVSDstore:
|
// Push to-be-stored value on top of stack.
|
push(s, v.Args[1])
|
|
// Pop and store value.
|
var op obj.As
|
switch v.Op {
|
case ssa.Op386MOVSSstore:
|
op = x86.AFMOVFP
|
case ssa.Op386MOVSDstore:
|
op = x86.AFMOVDP
|
}
|
p := s.Prog(op)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
p.To.Type = obj.TYPE_MEM
|
p.To.Reg = v.Args[0].Reg()
|
gc.AddAux(&p.To, v)
|
|
case ssa.Op386MOVSSstoreidx1, ssa.Op386MOVSDstoreidx1, ssa.Op386MOVSSstoreidx4, ssa.Op386MOVSDstoreidx8:
|
push(s, v.Args[2])
|
var op obj.As
|
switch v.Op {
|
case ssa.Op386MOVSSstoreidx1, ssa.Op386MOVSSstoreidx4:
|
op = x86.AFMOVFP
|
case ssa.Op386MOVSDstoreidx1, ssa.Op386MOVSDstoreidx8:
|
op = x86.AFMOVDP
|
}
|
p := s.Prog(op)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
p.To.Type = obj.TYPE_MEM
|
p.To.Reg = v.Args[0].Reg()
|
gc.AddAux(&p.To, v)
|
switch v.Op {
|
case ssa.Op386MOVSSstoreidx1, ssa.Op386MOVSDstoreidx1:
|
p.To.Scale = 1
|
p.To.Index = v.Args[1].Reg()
|
if p.To.Index == x86.REG_SP {
|
p.To.Reg, p.To.Index = p.To.Index, p.To.Reg
|
}
|
case ssa.Op386MOVSSstoreidx4:
|
p.To.Scale = 4
|
p.To.Index = v.Args[1].Reg()
|
case ssa.Op386MOVSDstoreidx8:
|
p.To.Scale = 8
|
p.To.Index = v.Args[1].Reg()
|
}
|
|
case ssa.Op386ADDSS, ssa.Op386ADDSD, ssa.Op386SUBSS, ssa.Op386SUBSD,
|
ssa.Op386MULSS, ssa.Op386MULSD, ssa.Op386DIVSS, ssa.Op386DIVSD:
|
if v.Reg() != v.Args[0].Reg() {
|
v.Fatalf("input[0] and output not in same register %s", v.LongString())
|
}
|
|
// Push arg1 on top of stack
|
push(s, v.Args[1])
|
|
// Set precision if needed. 64 bits is the default.
|
switch v.Op {
|
case ssa.Op386ADDSS, ssa.Op386SUBSS, ssa.Op386MULSS, ssa.Op386DIVSS:
|
p := s.Prog(x86.AFSTCW)
|
s.AddrScratch(&p.To)
|
p = s.Prog(x86.AFLDCW)
|
p.From.Type = obj.TYPE_MEM
|
p.From.Name = obj.NAME_EXTERN
|
p.From.Sym = gc.ControlWord32
|
}
|
|
var op obj.As
|
switch v.Op {
|
case ssa.Op386ADDSS, ssa.Op386ADDSD:
|
op = x86.AFADDDP
|
case ssa.Op386SUBSS, ssa.Op386SUBSD:
|
op = x86.AFSUBDP
|
case ssa.Op386MULSS, ssa.Op386MULSD:
|
op = x86.AFMULDP
|
case ssa.Op386DIVSS, ssa.Op386DIVSD:
|
op = x86.AFDIVDP
|
}
|
p := s.Prog(op)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = s.SSEto387[v.Reg()] + 1
|
|
// Restore precision if needed.
|
switch v.Op {
|
case ssa.Op386ADDSS, ssa.Op386SUBSS, ssa.Op386MULSS, ssa.Op386DIVSS:
|
p := s.Prog(x86.AFLDCW)
|
s.AddrScratch(&p.From)
|
}
|
|
case ssa.Op386UCOMISS, ssa.Op386UCOMISD:
|
push(s, v.Args[0])
|
|
// Compare.
|
p := s.Prog(x86.AFUCOMP)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = s.SSEto387[v.Args[1].Reg()] + 1
|
|
// Save AX.
|
p = s.Prog(x86.AMOVL)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_AX
|
s.AddrScratch(&p.To)
|
|
// Move status word into AX.
|
p = s.Prog(x86.AFSTSW)
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_AX
|
|
// Then move the flags we need to the integer flags.
|
s.Prog(x86.ASAHF)
|
|
// Restore AX.
|
p = s.Prog(x86.AMOVL)
|
s.AddrScratch(&p.From)
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_AX
|
|
case ssa.Op386SQRTSD:
|
push(s, v.Args[0])
|
s.Prog(x86.AFSQRT)
|
popAndSave(s, v)
|
|
case ssa.Op386FCHS:
|
push(s, v.Args[0])
|
s.Prog(x86.AFCHS)
|
popAndSave(s, v)
|
|
case ssa.Op386CVTSL2SS, ssa.Op386CVTSL2SD:
|
p := s.Prog(x86.AMOVL)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = v.Args[0].Reg()
|
s.AddrScratch(&p.To)
|
p = s.Prog(x86.AFMOVL)
|
s.AddrScratch(&p.From)
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
popAndSave(s, v)
|
|
case ssa.Op386CVTTSD2SL, ssa.Op386CVTTSS2SL:
|
push(s, v.Args[0])
|
|
// Save control word.
|
p := s.Prog(x86.AFSTCW)
|
s.AddrScratch(&p.To)
|
p.To.Offset += 4
|
|
// Load control word which truncates (rounds towards zero).
|
p = s.Prog(x86.AFLDCW)
|
p.From.Type = obj.TYPE_MEM
|
p.From.Name = obj.NAME_EXTERN
|
p.From.Sym = gc.ControlWord64trunc
|
|
// Now do the conversion.
|
p = s.Prog(x86.AFMOVLP)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
s.AddrScratch(&p.To)
|
p = s.Prog(x86.AMOVL)
|
s.AddrScratch(&p.From)
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = v.Reg()
|
|
// Restore control word.
|
p = s.Prog(x86.AFLDCW)
|
s.AddrScratch(&p.From)
|
p.From.Offset += 4
|
|
case ssa.Op386CVTSS2SD:
|
// float32 -> float64 is a nop
|
push(s, v.Args[0])
|
popAndSave(s, v)
|
|
case ssa.Op386CVTSD2SS:
|
// Round to nearest float32.
|
push(s, v.Args[0])
|
p := s.Prog(x86.AFMOVFP)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
s.AddrScratch(&p.To)
|
p = s.Prog(x86.AFMOVF)
|
s.AddrScratch(&p.From)
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
popAndSave(s, v)
|
|
case ssa.OpLoadReg:
|
if !v.Type.IsFloat() {
|
ssaGenValue(s, v)
|
return
|
}
|
// Load+push the value we need.
|
p := s.Prog(loadPush(v.Type))
|
gc.AddrAuto(&p.From, v.Args[0])
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
// Move the value to its assigned register.
|
popAndSave(s, v)
|
|
case ssa.OpStoreReg:
|
if !v.Type.IsFloat() {
|
ssaGenValue(s, v)
|
return
|
}
|
push(s, v.Args[0])
|
var op obj.As
|
switch v.Type.Size() {
|
case 4:
|
op = x86.AFMOVFP
|
case 8:
|
op = x86.AFMOVDP
|
}
|
p := s.Prog(op)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
gc.AddrAuto(&p.To, v)
|
|
case ssa.OpCopy:
|
if !v.Type.IsFloat() {
|
ssaGenValue(s, v)
|
return
|
}
|
push(s, v.Args[0])
|
popAndSave(s, v)
|
|
case ssa.Op386CALLstatic, ssa.Op386CALLclosure, ssa.Op386CALLinter:
|
flush387(s) // Calls must empty the FP stack.
|
fallthrough // then issue the call as normal
|
default:
|
ssaGenValue(s, v)
|
}
|
}
|
|
// push pushes v onto the floating-point stack. v must be in a register.
|
func push(s *gc.SSAGenState, v *ssa.Value) {
|
p := s.Prog(x86.AFMOVD)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = s.SSEto387[v.Reg()]
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
}
|
|
// popAndSave pops a value off of the floating-point stack and stores
|
// it in the reigster assigned to v.
|
func popAndSave(s *gc.SSAGenState, v *ssa.Value) {
|
r := v.Reg()
|
if _, ok := s.SSEto387[r]; ok {
|
// Pop value, write to correct register.
|
p := s.Prog(x86.AFMOVDP)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = s.SSEto387[v.Reg()] + 1
|
} else {
|
// Don't actually pop value. This 387 register is now the
|
// new home for the not-yet-assigned-a-home SSE register.
|
// Increase the register mapping of all other registers by one.
|
for rSSE, r387 := range s.SSEto387 {
|
s.SSEto387[rSSE] = r387 + 1
|
}
|
s.SSEto387[r] = x86.REG_F0
|
}
|
}
|
|
// loadPush returns the opcode for load+push of the given type.
|
func loadPush(t *types.Type) obj.As {
|
if t.Size() == 4 {
|
return x86.AFMOVF
|
}
|
return x86.AFMOVD
|
}
|
|
// flush387 removes all entries from the 387 floating-point stack.
|
func flush387(s *gc.SSAGenState) {
|
for k := range s.SSEto387 {
|
p := s.Prog(x86.AFMOVDP)
|
p.From.Type = obj.TYPE_REG
|
p.From.Reg = x86.REG_F0
|
p.To.Type = obj.TYPE_REG
|
p.To.Reg = x86.REG_F0
|
delete(s.SSEto387, k)
|
}
|
}
|
|
func ssaGenBlock387(s *gc.SSAGenState, b, next *ssa.Block) {
|
// Empty the 387's FP stack before the block ends.
|
flush387(s)
|
|
ssaGenBlock(s, b, next)
|
}
|
