golang
diff --git a/‎src/crypto/md5/gen.go
+62-133 b/‎src/crypto/md5/gen.go
+62-133
@@ -7,10 +7,7 @@
 // This program generates md5block.go
 // Invoke as
 //
-//	go run gen.go [-full] -output md5block.go
-//
-// The -full flag causes the generated code to do a full
-// (16x) unrolling instead of a 4x unrolling.
+//	go run gen.go -output md5block.go
 
 package main
 
@@ -56,13 +53,14 @@ type Data struct {
 	Table2     []uint32
 	Table3     []uint32
 	Table4     []uint32
-	Full       bool
 }
 
 var funcs = template.FuncMap{
 	"dup":     dup,
 	"relabel": relabel,
 	"rotate":  rotate,
+	"idx":     idx,
+	"seq":     seq,
 }
 
 func dup(count int, x []int) []int {
@@ -74,16 +72,35 @@ func dup(count int, x []int) []int {
 }
 
 func relabel(s string) string {
-	return strings.NewReplacer("a", data.a, "b", data.b, "c", data.c, "d", data.d).Replace(s)
+	return strings.NewReplacer("arg0", data.a, "arg1", data.b, "arg2", data.c, "arg3", data.d).Replace(s)
 }
 
 func rotate() string {
 	data.a, data.b, data.c, data.d = data.d, data.a, data.b, data.c
 	return "" // no output
 }
 
-func init() {
-	flag.BoolVar(&data.Full, "full", false, "complete unrolling")
+func idx(round, index int) int {
+	v := 0
+	switch round {
+	case 1:
+		v = index
+	case 2:
+		v = (1 + 5*index) & 15
+	case 3:
+		v = (5 + 3*index) & 15
+	case 4:
+		v = (7 * index) & 15
+	}
+	return v
+}
+
+func seq(i int) []int {
+	s := make([]int, i)
+	for i := range s {
+		s[i] = i
+	}
+	return s
 }
 
 var data = Data{
@@ -179,152 +196,64 @@ var program = `// Copyright 2013 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.
 
-// Code generated by go run gen.go{{if .Full}} -full{{end}} -output md5block.go; DO NOT EDIT.
+// Code generated by go run gen.go -output md5block.go; DO NOT EDIT.
 
 package md5
 
 import (
-	"unsafe"
-	"runtime"
+	"encoding/binary"
+	"math/bits"
 )
 
-{{if not .Full}}
-	var t1 = [...]uint32{
-	{{range .Table1}}{{printf "\t%#x,\n" .}}{{end}}
-	}
-	
-	var t2 = [...]uint32{
-	{{range .Table2}}{{printf "\t%#x,\n" .}}{{end}}
-	}
-	
-	var t3 = [...]uint32{
-	{{range .Table3}}{{printf "\t%#x,\n" .}}{{end}}
-	}
-	
-	var t4 = [...]uint32{
-	{{range .Table4}}{{printf "\t%#x,\n" .}}{{end}}
-	}
-{{end}}
-
-const x86 = runtime.GOARCH == "amd64" || runtime.GOARCH == "386"
-
-var littleEndian bool
+func blockGeneric(dig *digest, p []byte) {
+	// load state
+	a, b, c, d := dig.s[0], dig.s[1], dig.s[2], dig.s[3]
 
-func init() {
-	x := uint32(0x04030201)
-	y := [4]byte{0x1, 0x2, 0x3, 0x4}
-	littleEndian = *(*[4]byte)(unsafe.Pointer(&x)) == y
-}
+	for i := 0; i <= len(p)-BlockSize; i += BlockSize {
+		// eliminate bounds checks on p
+		q := p[i:]
+		q = q[:BlockSize:BlockSize]
 
-func blockGeneric(dig *digest, p []byte) {
-	a := dig.s[0]
-	b := dig.s[1]
-	c := dig.s[2]
-	d := dig.s[3]
-	var X *[16]uint32
-	var xbuf [16]uint32
-	for len(p) >= chunk {
+		// save current state
 		aa, bb, cc, dd := a, b, c, d
 
-		// This is a constant condition - it is not evaluated on each iteration.
-		if x86 {
-			// MD5 was designed so that x86 processors can just iterate
-			// over the block data directly as uint32s, and we generate
-			// less code and run 1.3x faster if we take advantage of that.
-			// My apologies.
-			X = (*[16]uint32)(unsafe.Pointer(&p[0]))
-		} else if littleEndian && uintptr(unsafe.Pointer(&p[0]))&(unsafe.Alignof(uint32(0))-1) == 0 {
-			X = (*[16]uint32)(unsafe.Pointer(&p[0]))
-		} else {
-			X = &xbuf
-			j := 0
-			for i := 0; i < 16; i++ {
-				X[i&15] = uint32(p[j]) | uint32(p[j+1])<<8 | uint32(p[j+2])<<16 | uint32(p[j+3])<<24
-				j += 4
-			}
-		}
+		// load input block
+		{{range $i := seq 16 -}}
+			{{printf "x%x := binary.LittleEndian.Uint32(q[4*%#x:])" $i $i}}
+		{{end}}
 
-		{{if .Full}}
-			// Round 1.
-			{{range $i, $s := dup 4 .Shift1}}
-				{{index $.Table1 $i | printf "a += (((c^d)&b)^d) + X[%d] + %d" $i | relabel}}
-				{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-				{{rotate}}
-			{{end}}
-	
-			// Round 2.
-			{{range $i, $s := dup 4 .Shift2}}
-				{{index $.Table2 $i | printf "a += (((b^c)&d)^c) + X[(1+5*%d)&15] + %d" $i | relabel}}
-				{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-				{{rotate}}
-			{{end}}
-	
-			// Round 3.
-			{{range $i, $s := dup 4 .Shift3}}
-				{{index $.Table3 $i | printf "a += (b^c^d) + X[(5+3*%d)&15] + %d" $i | relabel}}
-				{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-				{{rotate}}
-			{{end}}
-	
-			// Round 4.
-			{{range $i, $s := dup 4 .Shift4}}
-				{{index $.Table4 $i | printf "a += (c^(b|^d)) + X[(7*%d)&15] + %d" $i | relabel}}
-				{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-				{{rotate}}
-			{{end}}
-		{{else}}
-			// Round 1.
-			for i := uint(0); i < 16; {
-				{{range $s := .Shift1}}
-					{{printf "a += (((c^d)&b)^d) + X[i&15] + t1[i&15]" | relabel}}
-					{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-					i++
-					{{rotate}}
-				{{end}}
-			}
+		// round 1
+		{{range $i, $s := dup 4 .Shift1 -}}
+			{{printf "arg0 = arg1 + bits.RotateLeft32((((arg2^arg3)&arg1)^arg3)+arg0+x%x+%#08x, %d)" (idx 1 $i) (index $.Table1 $i) $s | relabel}}
+			{{rotate -}}
+		{{end}}
 	
-			// Round 2.
-			for i := uint(0); i < 16; {
-				{{range $s := .Shift2}}
-					{{printf "a += (((b^c)&d)^c) + X[(1+5*i)&15] + t2[i&15]" | relabel}}
-					{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-					i++
-					{{rotate}}
-				{{end}}
-			}
+		// round 2
+		{{range $i, $s := dup 4 .Shift2 -}}
+			{{printf "arg0 = arg1 + bits.RotateLeft32((((arg1^arg2)&arg3)^arg2)+arg0+x%x+%#08x, %d)" (idx 2 $i) (index $.Table2 $i) $s | relabel}}
+			{{rotate -}}
+		{{end}}
 	
-			// Round 3.
-			for i := uint(0); i < 16; {
-				{{range $s := .Shift3}}
-					{{printf "a += (b^c^d) + X[(5+3*i)&15] + t3[i&15]" | relabel}}
-					{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-					i++
-					{{rotate}}
-				{{end}}
-			}
+		// round 3
+		{{range $i, $s := dup 4 .Shift3 -}}
+			{{printf "arg0 = arg1 + bits.RotateLeft32((arg1^arg2^arg3)+arg0+x%x+%#08x, %d)" (idx 3 $i) (index $.Table3 $i) $s | relabel}}
+			{{rotate -}}
+		{{end}}
 	
-			// Round 4.
-			for i := uint(0); i < 16; {
-				{{range $s := .Shift4}}
-					{{printf "a += (c^(b|^d)) + X[(7*i)&15] + t4[i&15]" | relabel}}
-					{{printf "a = a<<%d | a>>(32-%d) + b" $s $s | relabel}}
-					i++
-					{{rotate}}
-				{{end}}
-			}
+		// round 4
+		{{range $i, $s := dup 4 .Shift4 -}}
+			{{printf "arg0 = arg1 + bits.RotateLeft32((arg2^(arg1|^arg3))+arg0+x%x+%#08x, %d)" (idx 4 $i) (index $.Table4 $i) $s | relabel}}
+			{{rotate -}}
 		{{end}}
 
+		// add saved state
 		a += aa
 		b += bb
 		c += cc
 		d += dd
-
-		p = p[chunk:]
 	}
 
-	dig.s[0] = a
-	dig.s[1] = b
-	dig.s[2] = c
-	dig.s[3] = d
+	// save state
+	dig.s[0], dig.s[1], dig.s[2], dig.s[3] = a, b, c, d
 }
 `