src/runtime/mkduff.go - go - Git at Google

 // 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.

 //go: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("loong64", notags, zeroLOONG64, copyLOONG64)
 	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) {
 	// X15: zero
 	// DI: ptr to memory to be zeroed
 	// DI is updated as a side effect.
 	fmt.Fprintln(w, "TEXT runtime·duffzero<ABIInternal>(SB), NOSPLIT, $0-0")
 	for i := 0; i < 16; i++ {
 		fmt.Fprintln(w, "\tMOVUPS\tX15,(DI)")
 		fmt.Fprintln(w, "\tMOVUPS\tX15,16(DI)")
 		fmt.Fprintln(w, "\tMOVUPS\tX15,32(DI)")
 		fmt.Fprintln(w, "\tMOVUPS\tX15,48(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<ABIInternal>(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<ABIInternal>(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<ABIInternal>(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 zeroLOONG64(w io.Writer) {
 	// R0: always zero
 	// R19 (aka REGRT1): ptr to memory to be zeroed - 8
 	// On return, R19 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(R19)")
 		fmt.Fprintln(w, "\tADDV\t$8, R19")
 	}
 	fmt.Fprintln(w, "\tRET")
 }

 func copyLOONG64(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(R19), R30")
 		fmt.Fprintln(w, "\tADDV\t$8, R19")
 		fmt.Fprintln(w, "\tMOVV\tR30, (R20)")
 		fmt.Fprintln(w, "\tADDV\t$8, R20")
 		fmt.Fprintln(w)
 	}
 	fmt.Fprintln(w, "\tRET")
 }

 func tagsPPC64x(w io.Writer) {
 	fmt.Fprintln(w)
 	fmt.Fprintln(w, "//go: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<ABIInternal>(SB), NOSPLIT|NOFRAME, $0-0")
 	for i := 0; i < 128; i++ {
 		fmt.Fprintln(w, "\tMOVDU\tR0, 8(R20)")
 	}
 	fmt.Fprintln(w, "\tRET")
 }

 func copyPPC64x(w io.Writer) {
 	// duffcopy is not used on PPC64.
 	fmt.Fprintln(w, "TEXT runtime·duffcopy<ABIInternal>(SB), NOSPLIT|NOFRAME, $0-0")
 	for i := 0; i < 128; i++ {
 		fmt.Fprintln(w, "\tMOVDU\t8(R20), R5")
 		fmt.Fprintln(w, "\tMOVDU\tR5, 8(R21)")
 	}
 	fmt.Fprintln(w, "\tRET")
 }

 func tagsMIPS64x(w io.Writer) {
 	fmt.Fprintln(w)
 	fmt.Fprintln(w, "//go: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
 	// X25: ptr to memory to be zeroed
 	// X25 is updated as a side effect.
 	fmt.Fprintln(w, "TEXT runtime·duffzero<ABIInternal>(SB), NOSPLIT|NOFRAME, $0-0")
 	for i := 0; i < 128; i++ {
 		fmt.Fprintln(w, "\tMOV\tZERO, (X25)")
 		fmt.Fprintln(w, "\tADD\t$8, X25")
 	}
 	fmt.Fprintln(w, "\tRET")
 }

 func copyRISCV64(w io.Writer) {
 	// X24: ptr to source memory
 	// X25: ptr to destination memory
 	// X24 and X25 are updated as a side effect
 	fmt.Fprintln(w, "TEXT runtime·duffcopy<ABIInternal>(SB), NOSPLIT|NOFRAME, $0-0")
 	for i := 0; i < 128; i++ {
 		fmt.Fprintln(w, "\tMOV\t(X24), X31")
 		fmt.Fprintln(w, "\tADD\t$8, X24")
 		fmt.Fprintln(w, "\tMOV\tX31, (X25)")
 		fmt.Fprintln(w, "\tADD\t$8, X25")
 		fmt.Fprintln(w)
 	}
 	fmt.Fprintln(w, "\tRET")
 }
	// 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.

	//go: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("loong64", notags, zeroLOONG64, copyLOONG64)
	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) {
	// X15: zero
	// DI: ptr to memory to be zeroed
	// DI is updated as a side effect.
	fmt.Fprintln(w, "TEXT runtime·duffzero<ABIInternal>(SB), NOSPLIT, $0-0")
	for i := 0; i < 16; i++ {
	fmt.Fprintln(w, "\tMOVUPS\tX15,(DI)")
	fmt.Fprintln(w, "\tMOVUPS\tX15,16(DI)")
	fmt.Fprintln(w, "\tMOVUPS\tX15,32(DI)")
	fmt.Fprintln(w, "\tMOVUPS\tX15,48(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<ABIInternal>(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<ABIInternal>(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<ABIInternal>(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 zeroLOONG64(w io.Writer) {
	// R0: always zero
	// R19 (aka REGRT1): ptr to memory to be zeroed - 8
	// On return, R19 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(R19)")
	fmt.Fprintln(w, "\tADDV\t$8, R19")
	}
	fmt.Fprintln(w, "\tRET")
	}

	func copyLOONG64(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(R19), R30")
	fmt.Fprintln(w, "\tADDV\t$8, R19")
	fmt.Fprintln(w, "\tMOVV\tR30, (R20)")
	fmt.Fprintln(w, "\tADDV\t$8, R20")
	fmt.Fprintln(w)
	}
	fmt.Fprintln(w, "\tRET")
	}

	func tagsPPC64x(w io.Writer) {
	fmt.Fprintln(w)
	fmt.Fprintln(w, "//go: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<ABIInternal>(SB), NOSPLIT\|NOFRAME, $0-0")
	for i := 0; i < 128; i++ {
	fmt.Fprintln(w, "\tMOVDU\tR0, 8(R20)")
	}
	fmt.Fprintln(w, "\tRET")
	}

	func copyPPC64x(w io.Writer) {
	// duffcopy is not used on PPC64.
	fmt.Fprintln(w, "TEXT runtime·duffcopy<ABIInternal>(SB), NOSPLIT\|NOFRAME, $0-0")
	for i := 0; i < 128; i++ {
	fmt.Fprintln(w, "\tMOVDU\t8(R20), R5")
	fmt.Fprintln(w, "\tMOVDU\tR5, 8(R21)")
	}
	fmt.Fprintln(w, "\tRET")
	}

	func tagsMIPS64x(w io.Writer) {
	fmt.Fprintln(w)
	fmt.Fprintln(w, "//go: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
	// X25: ptr to memory to be zeroed
	// X25 is updated as a side effect.
	fmt.Fprintln(w, "TEXT runtime·duffzero<ABIInternal>(SB), NOSPLIT\|NOFRAME, $0-0")
	for i := 0; i < 128; i++ {
	fmt.Fprintln(w, "\tMOV\tZERO, (X25)")
	fmt.Fprintln(w, "\tADD\t$8, X25")
	}
	fmt.Fprintln(w, "\tRET")
	}

	func copyRISCV64(w io.Writer) {
	// X24: ptr to source memory
	// X25: ptr to destination memory
	// X24 and X25 are updated as a side effect
	fmt.Fprintln(w, "TEXT runtime·duffcopy<ABIInternal>(SB), NOSPLIT\|NOFRAME, $0-0")
	for i := 0; i < 128; i++ {
	fmt.Fprintln(w, "\tMOV\t(X24), X31")
	fmt.Fprintln(w, "\tADD\t$8, X24")
	fmt.Fprintln(w, "\tMOV\tX31, (X25)")
	fmt.Fprintln(w, "\tADD\t$8, X25")
	fmt.Fprintln(w)
	}
	fmt.Fprintln(w, "\tRET")
	}