--- /dev/null
+// 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 clearfat in cmd/?g/ggen.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 stackcopy in cmd/?g/cgen.go.
+
+// See the zero* and copy* generators below
+// for architecture-specific comments.
+
+// mkduff generates duff_*.s.
+package main
+
+import (
+ "bytes"
+ "fmt"
+ "io"
+ "io/ioutil"
+ "log"
+)
+
+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)
+}
+
+func gen(arch string, tags, zero, copy func(io.Writer)) {
+ var buf bytes.Buffer
+
+ fmt.Fprintln(&buf, "// AUTO-GENERATED by mkduff.go")
+ 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 := ioutil.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) {
+ // 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, "\tSTOSQ")
+ }
+ 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.
+ // The STOSQ in duffzero seem fine, though.
+ fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT, $0-0")
+ for i := 0; i < 128; i++ {
+ fmt.Fprintln(w, "\tMOVQ\t(SI), CX")
+ fmt.Fprintln(w, "\tADDQ\t$8, SI")
+ fmt.Fprintln(w, "\tMOVQ\tCX, (DI)")
+ fmt.Fprintln(w, "\tADDQ\t$8, 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
+ // R16 (aka REGRT1): ptr to memory to be zeroed - 8
+ // On return, R16 points to the last zeroed dword.
+ fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $-8-0")
+ for i := 0; i < 128; i++ {
+ fmt.Fprintln(w, "\tMOVD.W\tZR, 8(R16)")
+ }
+ fmt.Fprintln(w, "\tRET")
+}
+
+func copyARM64(w io.Writer) {
+ fmt.Fprintln(w, "// TODO: Implement runtime·duffcopy.")
+}
+
+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, $-8-0")
+ for i := 0; i < 128; i++ {
+ fmt.Fprintln(w, "\tMOVDU\tR0, 8(R3)")
+ }
+ fmt.Fprintln(w, "\tRETURN")
+}
+
+func copyPPC64x(w io.Writer) {
+ fmt.Fprintln(w, "// TODO: Implement runtime·duffcopy.")
+}