/
cgen.go
178 lines (156 loc) · 3.63 KB
/
cgen.go
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// 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 s390x
import (
"cmd/compile/internal/gc"
"cmd/internal/obj"
"cmd/internal/obj/s390x"
)
type direction int
const (
_FORWARDS direction = iota
_BACKWARDS
)
// blockcopy copies w bytes from &n to &res
func blockcopy(n, res *gc.Node, osrc, odst, w int64) {
var dst gc.Node
var src gc.Node
if n.Ullman >= res.Ullman {
gc.Agenr(n, &dst, res) // temporarily use dst
gc.Regalloc(&src, gc.Types[gc.Tptr], nil)
gins(s390x.AMOVD, &dst, &src)
if res.Op == gc.ONAME {
gc.Gvardef(res)
}
gc.Agen(res, &dst)
} else {
if res.Op == gc.ONAME {
gc.Gvardef(res)
}
gc.Agenr(res, &dst, res)
gc.Agenr(n, &src, nil)
}
defer gc.Regfree(&src)
defer gc.Regfree(&dst)
var tmp gc.Node
gc.Regalloc(&tmp, gc.Types[gc.Tptr], nil)
defer gc.Regfree(&tmp)
offset := int64(0)
dir := _FORWARDS
if osrc < odst && odst < osrc+w {
// Reverse. Can't use MVC, fall back onto basic moves.
dir = _BACKWARDS
const copiesPerIter = 2
if w >= 8*copiesPerIter {
cnt := w - (w % (8 * copiesPerIter))
ginscon(s390x.AADD, w, &src)
ginscon(s390x.AADD, w, &dst)
var end gc.Node
gc.Regalloc(&end, gc.Types[gc.Tptr], nil)
p := gins(s390x.ASUB, nil, &end)
p.From.Type = obj.TYPE_CONST
p.From.Offset = cnt
p.Reg = src.Reg
var label *obj.Prog
for i := 0; i < copiesPerIter; i++ {
offset := int64(-8 * (i + 1))
p := gins(s390x.AMOVD, &src, &tmp)
p.From.Type = obj.TYPE_MEM
p.From.Offset = offset
if i == 0 {
label = p
}
p = gins(s390x.AMOVD, &tmp, &dst)
p.To.Type = obj.TYPE_MEM
p.To.Offset = offset
}
ginscon(s390x.ASUB, 8*copiesPerIter, &src)
ginscon(s390x.ASUB, 8*copiesPerIter, &dst)
gins(s390x.ACMP, &src, &end)
gc.Patch(gc.Gbranch(s390x.ABNE, nil, 0), label)
gc.Regfree(&end)
w -= cnt
} else {
offset = w
}
}
if dir == _FORWARDS && w > 1024 {
// Loop over MVCs
cnt := w - (w % 256)
var end gc.Node
gc.Regalloc(&end, gc.Types[gc.Tptr], nil)
add := gins(s390x.AADD, nil, &end)
add.From.Type = obj.TYPE_CONST
add.From.Offset = cnt
add.Reg = src.Reg
mvc := gins(s390x.AMVC, &src, &dst)
mvc.From.Type = obj.TYPE_MEM
mvc.From.Offset = 0
mvc.To.Type = obj.TYPE_MEM
mvc.To.Offset = 0
mvc.From3 = new(obj.Addr)
mvc.From3.Type = obj.TYPE_CONST
mvc.From3.Offset = 256
ginscon(s390x.AADD, 256, &src)
ginscon(s390x.AADD, 256, &dst)
gins(s390x.ACMP, &src, &end)
gc.Patch(gc.Gbranch(s390x.ABNE, nil, 0), mvc)
gc.Regfree(&end)
w -= cnt
}
for w > 0 {
cnt := w
// If in reverse we can only do 8, 4, 2 or 1 bytes at a time.
if dir == _BACKWARDS {
switch {
case cnt >= 8:
cnt = 8
case cnt >= 4:
cnt = 4
case cnt >= 2:
cnt = 2
}
} else if cnt > 256 {
cnt = 256
}
switch cnt {
case 8, 4, 2, 1:
op := s390x.AMOVB
switch cnt {
case 8:
op = s390x.AMOVD
case 4:
op = s390x.AMOVW
case 2:
op = s390x.AMOVH
}
load := gins(op, &src, &tmp)
load.From.Type = obj.TYPE_MEM
load.From.Offset = offset
store := gins(op, &tmp, &dst)
store.To.Type = obj.TYPE_MEM
store.To.Offset = offset
if dir == _BACKWARDS {
load.From.Offset -= cnt
store.To.Offset -= cnt
}
default:
p := gins(s390x.AMVC, &src, &dst)
p.From.Type = obj.TYPE_MEM
p.From.Offset = offset
p.To.Type = obj.TYPE_MEM
p.To.Offset = offset
p.From3 = new(obj.Addr)
p.From3.Type = obj.TYPE_CONST
p.From3.Offset = cnt
}
switch dir {
case _FORWARDS:
offset += cnt
case _BACKWARDS:
offset -= cnt
}
w -= cnt
}
}