golang-image/vector/gen.go
Nigel Tao ae7296db94 vector: generate acc_amd64.s from a template.
There are currently 2 instantiations: fixed and floating math.

There will eventually be 6: 2 math types times 3 operators (OpOver,
OpSrc and Mask).

Change-Id: I16db8f3693abe30027ea2f822909980403a6142f
Reviewed-on: https://go-review.googlesource.com/30735
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-10-11 07:55:43 +00:00

179 lines
4.2 KiB
Go

// 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.
// +build ignore
package main
import (
"bytes"
"io/ioutil"
"log"
"text/template"
)
const (
copyright = "" +
"// Copyright 2016 The Go Authors. All rights reserved.\n" +
"// Use of this source code is governed by a BSD-style\n" +
"// license that can be found in the LICENSE file.\n"
doNotEdit = "// generated by go run gen.go; DO NOT EDIT\n"
dashDashDash = "// --------"
)
func main() {
tmpl, err := ioutil.ReadFile("gen_acc_amd64.s.tmpl")
if err != nil {
log.Fatalf("ReadFile: %v", err)
}
if !bytes.HasPrefix(tmpl, []byte(copyright)) {
log.Fatal("source template did not start with the copyright header")
}
tmpl = tmpl[len(copyright):]
preamble := []byte(nil)
if i := bytes.Index(tmpl, []byte(dashDashDash)); i < 0 {
log.Fatalf("source template did not contain %q", dashDashDash)
} else {
preamble, tmpl = tmpl[:i], tmpl[i:]
}
t, err := template.New("").Parse(string(tmpl))
if err != nil {
log.Fatalf("Parse: %v", err)
}
out := bytes.NewBuffer(nil)
out.WriteString(doNotEdit)
out.Write(preamble)
for i, v := range instances {
if i != 0 {
out.WriteString("\n")
}
if err := t.Execute(out, v); err != nil {
log.Fatalf("Execute(%q): %v", v.ShortName, err)
}
}
if err := ioutil.WriteFile("acc_amd64.s", out.Bytes(), 0666); err != nil {
log.Fatalf("WriteFile: %v", err)
}
}
var instances = []struct {
LongName string
ShortName string
FrameSize string
SrcType string
XMM3 string
XMM4 string
XMM5 string
Setup string
Cleanup string
Add string
ClampAndScale string
ConvertToInt32 string
}{{
LongName: "fixedAccumulateOpSrc",
ShortName: "fxAccOpSrc",
FrameSize: fxFrameSize,
SrcType: fxSrcType,
XMM3: fxXMM3,
XMM4: fxXMM4,
XMM5: fxXMM5,
Setup: fxSetup,
Cleanup: fxCleanup,
Add: fxAdd,
ClampAndScale: fxClampAndScale,
ConvertToInt32: fxConvertToInt32,
}, {
LongName: "floatingAccumulateOpSrc",
ShortName: "flAccOpSrc",
FrameSize: flFrameSize,
SrcType: flSrcType,
XMM3: flXMM3,
XMM4: flXMM4,
XMM5: flXMM5,
Setup: flSetup,
Cleanup: flCleanup,
Add: flAdd,
ClampAndScale: flClampAndScale,
ConvertToInt32: flConvertToInt32,
}}
const (
fxFrameSize = `0`
flFrameSize = `8`
fxSrcType = `[]uint32`
flSrcType = `[]float32`
fxXMM3 = `-`
flXMM3 = `flAlmost256`
fxXMM4 = `-`
flXMM4 = `flOne`
fxXMM5 = `fxAlmost256`
flXMM5 = `flSignMask`
fxSetup = `
// fxAlmost256 := XMM(0x000000ff repeated four times) // Maximum of an uint8.
MOVOU fxAlmost256<>(SB), X5
`
flSetup = `
// Set MXCSR bits 13 and 14, so that the CVTPS2PL below is "Round To Zero".
STMXCSR mxcsrOrig-8(SP)
MOVL mxcsrOrig-8(SP), AX
ORL $0x6000, AX
MOVL AX, mxcsrNew-4(SP)
LDMXCSR mxcsrNew-4(SP)
// flAlmost256 := XMM(0x437fffff repeated four times) // 255.99998 as a float32.
// flOne := XMM(0x3f800000 repeated four times) // 1 as a float32.
// flSignMask := XMM(0x7fffffff repeated four times) // All but the sign bit of a float32.
MOVOU flAlmost256<>(SB), X3
MOVOU flOne<>(SB), X4
MOVOU flSignMask<>(SB), X5
`
fxCleanup = `// No-op.`
flCleanup = `LDMXCSR mxcsrOrig-8(SP)`
fxAdd = `PADDD`
flAdd = `ADDPS`
fxClampAndScale = `
// y = abs(x)
// y >>= 12 // Shift by 2*ϕ - 8.
// y = min(y, fxAlmost256)
//
// pabsd %xmm1,%xmm2
// psrld $0xc,%xmm2
// pminud %xmm5,%xmm2
//
// Hopefully we'll get these opcode mnemonics into the assembler for Go
// 1.8. https://golang.org/issue/16007 isn't exactly the same thing, but
// it's similar.
BYTE $0x66; BYTE $0x0f; BYTE $0x38; BYTE $0x1e; BYTE $0xd1
BYTE $0x66; BYTE $0x0f; BYTE $0x72; BYTE $0xd2; BYTE $0x0c
BYTE $0x66; BYTE $0x0f; BYTE $0x38; BYTE $0x3b; BYTE $0xd5
`
flClampAndScale = `
// y = x & flSignMask
// y = min(y, flOne)
// y = mul(y, flAlmost256)
MOVOU X5, X2
ANDPS X1, X2
MINPS X4, X2
MULPS X3, X2
`
fxConvertToInt32 = `// No-op.`
flConvertToInt32 = `CVTPS2PL X2, X2`
)