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// Copyright 2015 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
// runtime·duffzero is a Duff's device for zeroing memory.
// The compiler jumps to computed addresses within
// the routine to zero chunks of memory.
// Do not change duffzero without also
// changing the uses in cmd/compile/internal/*/*.go.
// runtime·duffcopy is a Duff's device for copying memory.
// The compiler jumps to computed addresses within
// the routine to copy chunks of memory.
// Source and destination must not overlap.
// Do not change duffcopy without also
// changing the uses in cmd/compile/internal/*/*.go.
// See the zero* and copy* generators below
// for architecture-specific comments.
// mkduff generates duff_*.s.
package main
import (
"bytes"
"fmt"
"io"
"log"
"os"
)
func main() {
gen("amd64", notags, zeroAMD64, copyAMD64)
gen("386", notags, zero386, copy386)
gen("arm", notags, zeroARM, copyARM)
gen("arm64", notags, zeroARM64, copyARM64)
gen("ppc64x", tagsPPC64x, zeroPPC64x, copyPPC64x)
gen("mips64x", tagsMIPS64x, zeroMIPS64x, copyMIPS64x)
gen("riscv64", notags, zeroRISCV64, copyRISCV64)
}
func gen(arch string, tags, zero, copy func(io.Writer)) {
var buf bytes.Buffer
fmt.Fprintln(&buf, "// Code generated by mkduff.go; DO NOT EDIT.")
fmt.Fprintln(&buf, "// Run go generate from src/runtime to update.")
fmt.Fprintln(&buf, "// See mkduff.go for comments.")
tags(&buf)
fmt.Fprintln(&buf, "#include \"textflag.h\"")
fmt.Fprintln(&buf)
zero(&buf)
fmt.Fprintln(&buf)
copy(&buf)
if err := os.WriteFile("duff_"+arch+".s", buf.Bytes(), 0644); err != nil {
log.Fatalln(err)
}
}
func notags(w io.Writer) { fmt.Fprintln(w) }
func zeroAMD64(w io.Writer) {
// X0: zero
// DI: ptr to memory to be zeroed
// DI is updated as a side effect.
fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $0-0")
for i := 0; i < 16; i++ {
fmt.Fprintln(w, "\tMOVUPS\tX0,(DI)")
fmt.Fprintln(w, "\tMOVUPS\tX0,16(DI)")
fmt.Fprintln(w, "\tMOVUPS\tX0,32(DI)")
fmt.Fprintln(w, "\tMOVUPS\tX0,48(DI)")
fmt.Fprintln(w, "\tLEAQ\t64(DI),DI") // We use lea instead of add, to avoid clobbering flags
fmt.Fprintln(w)
}
fmt.Fprintln(w, "\tRET")
}
func copyAMD64(w io.Writer) {
// SI: ptr to source memory
// DI: ptr to destination memory
// SI and DI are updated as a side effect.
//
// This is equivalent to a sequence of MOVSQ but
// for some reason that is 3.5x slower than this code.
fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT, $0-0")
for i := 0; i < 64; i++ {
fmt.Fprintln(w, "\tMOVUPS\t(SI), X0")
fmt.Fprintln(w, "\tADDQ\t$16, SI")
fmt.Fprintln(w, "\tMOVUPS\tX0, (DI)")
fmt.Fprintln(w, "\tADDQ\t$16, DI")
fmt.Fprintln(w)
}
fmt.Fprintln(w, "\tRET")
}
func zero386(w io.Writer) {
// AX: zero
// DI: ptr to memory to be zeroed
// DI is updated as a side effect.
fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tSTOSL")
}
fmt.Fprintln(w, "\tRET")
}
func copy386(w io.Writer) {
// SI: ptr to source memory
// DI: ptr to destination memory
// SI and DI are updated as a side effect.
//
// This is equivalent to a sequence of MOVSL but
// for some reason MOVSL is really slow.
fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOVL\t(SI), CX")
fmt.Fprintln(w, "\tADDL\t$4, SI")
fmt.Fprintln(w, "\tMOVL\tCX, (DI)")
fmt.Fprintln(w, "\tADDL\t$4, DI")
fmt.Fprintln(w)
}
fmt.Fprintln(w, "\tRET")
}
func zeroARM(w io.Writer) {
// R0: zero
// R1: ptr to memory to be zeroed
// R1 is updated as a side effect.
fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOVW.P\tR0, 4(R1)")
}
fmt.Fprintln(w, "\tRET")
}
func copyARM(w io.Writer) {
// R0: scratch space
// R1: ptr to source memory
// R2: ptr to destination memory
// R1 and R2 are updated as a side effect
fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOVW.P\t4(R1), R0")
fmt.Fprintln(w, "\tMOVW.P\tR0, 4(R2)")
fmt.Fprintln(w)
}
fmt.Fprintln(w, "\tRET")
}
func zeroARM64(w io.Writer) {
// ZR: always zero
// R20: ptr to memory to be zeroed
// On return, R20 points to the last zeroed dword.
fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT|NOFRAME, $0-0")
for i := 0; i < 63; i++ {
fmt.Fprintln(w, "\tSTP.P\t(ZR, ZR), 16(R20)")
}
fmt.Fprintln(w, "\tSTP\t(ZR, ZR), (R20)")
fmt.Fprintln(w, "\tRET")
}
func copyARM64(w io.Writer) {
// R20: ptr to source memory
// R21: ptr to destination memory
// R26, R27 (aka REGTMP): scratch space
// R20 and R21 are updated as a side effect
fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT|NOFRAME, $0-0")
for i := 0; i < 64; i++ {
fmt.Fprintln(w, "\tLDP.P\t16(R20), (R26, R27)")
fmt.Fprintln(w, "\tSTP.P\t(R26, R27), 16(R21)")
fmt.Fprintln(w)
}
fmt.Fprintln(w, "\tRET")
}
func tagsPPC64x(w io.Writer) {
fmt.Fprintln(w)
fmt.Fprintln(w, "// +build ppc64 ppc64le")
fmt.Fprintln(w)
}
func zeroPPC64x(w io.Writer) {
// R0: always zero
// R3 (aka REGRT1): ptr to memory to be zeroed - 8
// On return, R3 points to the last zeroed dword.
fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT|NOFRAME, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOVDU\tR0, 8(R3)")
}
fmt.Fprintln(w, "\tRET")
}
func copyPPC64x(w io.Writer) {
// duffcopy is not used on PPC64.
fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT|NOFRAME, $0-0")
fmt.Fprintln(w, "\tUNDEF")
}
func tagsMIPS64x(w io.Writer) {
fmt.Fprintln(w)
fmt.Fprintln(w, "// +build mips64 mips64le")
fmt.Fprintln(w)
}
func zeroMIPS64x(w io.Writer) {
// R0: always zero
// R1 (aka REGRT1): ptr to memory to be zeroed - 8
// On return, R1 points to the last zeroed dword.
fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT|NOFRAME, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOVV\tR0, 8(R1)")
fmt.Fprintln(w, "\tADDV\t$8, R1")
}
fmt.Fprintln(w, "\tRET")
}
func copyMIPS64x(w io.Writer) {
fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT|NOFRAME, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOVV\t(R1), R23")
fmt.Fprintln(w, "\tADDV\t$8, R1")
fmt.Fprintln(w, "\tMOVV\tR23, (R2)")
fmt.Fprintln(w, "\tADDV\t$8, R2")
fmt.Fprintln(w)
}
fmt.Fprintln(w, "\tRET")
}
func zeroRISCV64(w io.Writer) {
// ZERO: always zero
// X10: ptr to memory to be zeroed
// X10 is updated as a side effect.
fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT|NOFRAME, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOV\tZERO, (X10)")
fmt.Fprintln(w, "\tADD\t$8, X10")
}
fmt.Fprintln(w, "\tRET")
}
func copyRISCV64(w io.Writer) {
// X10: ptr to source memory
// X11: ptr to destination memory
// X10 and X11 are updated as a side effect
fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT|NOFRAME, $0-0")
for i := 0; i < 128; i++ {
fmt.Fprintln(w, "\tMOV\t(X10), X31")
fmt.Fprintln(w, "\tADD\t$8, X10")
fmt.Fprintln(w, "\tMOV\tX31, (X11)")
fmt.Fprintln(w, "\tADD\t$8, X11")
fmt.Fprintln(w)
}
fmt.Fprintln(w, "\tRET")
}
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