diff options
Diffstat (limited to 'src/pkg/crypto/md5/gen.go')
| -rw-r--r-- | src/pkg/crypto/md5/gen.go | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/src/pkg/crypto/md5/gen.go b/src/pkg/crypto/md5/gen.go new file mode 100644 index 000000000..966bdae26 --- /dev/null +++ b/src/pkg/crypto/md5/gen.go @@ -0,0 +1,300 @@ +// Copyright 2012 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 + +// This program generates md5block.go +// Invoke as +// +// go run gen.go [-full] |gofmt >md5block.go +// +// The -full flag causes the generated code to do a full +// (16x) unrolling instead of a 4x unrolling. + +package main + +import ( + "flag" + "log" + "os" + "strings" + "text/template" +) + +func main() { + flag.Parse() + + t := template.Must(template.New("main").Funcs(funcs).Parse(program)) + if err := t.Execute(os.Stdout, data); err != nil { + log.Fatal(err) + } +} + +type Data struct { + a, b, c, d string + Shift1 []int + Shift2 []int + Shift3 []int + Shift4 []int + Table1 []uint32 + Table2 []uint32 + Table3 []uint32 + Table4 []uint32 + Full bool +} + +var funcs = template.FuncMap{ + "dup": dup, + "relabel": relabel, + "rotate": rotate, +} + +func dup(count int, x []int) []int { + var out []int + for i := 0; i < count; i++ { + out = append(out, x...) + } + return out +} + +func relabel(s string) string { + return strings.NewReplacer("a", data.a, "b", data.b, "c", data.c, "d", 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") +} + +var data = Data{ + a: "a", + b: "b", + c: "c", + d: "d", + Shift1: []int{7, 12, 17, 22}, + Shift2: []int{5, 9, 14, 20}, + Shift3: []int{4, 11, 16, 23}, + Shift4: []int{6, 10, 15, 21}, + + // table[i] = int((1<<32) * abs(sin(i+1 radians))). + Table1: []uint32{ + // round 1 + 0xd76aa478, + 0xe8c7b756, + 0x242070db, + 0xc1bdceee, + 0xf57c0faf, + 0x4787c62a, + 0xa8304613, + 0xfd469501, + 0x698098d8, + 0x8b44f7af, + 0xffff5bb1, + 0x895cd7be, + 0x6b901122, + 0xfd987193, + 0xa679438e, + 0x49b40821, + }, + Table2: []uint32{ + // round 2 + 0xf61e2562, + 0xc040b340, + 0x265e5a51, + 0xe9b6c7aa, + 0xd62f105d, + 0x2441453, + 0xd8a1e681, + 0xe7d3fbc8, + 0x21e1cde6, + 0xc33707d6, + 0xf4d50d87, + 0x455a14ed, + 0xa9e3e905, + 0xfcefa3f8, + 0x676f02d9, + 0x8d2a4c8a, + }, + Table3: []uint32{ + // round3 + 0xfffa3942, + 0x8771f681, + 0x6d9d6122, + 0xfde5380c, + 0xa4beea44, + 0x4bdecfa9, + 0xf6bb4b60, + 0xbebfbc70, + 0x289b7ec6, + 0xeaa127fa, + 0xd4ef3085, + 0x4881d05, + 0xd9d4d039, + 0xe6db99e5, + 0x1fa27cf8, + 0xc4ac5665, + }, + Table4: []uint32{ + // round 4 + 0xf4292244, + 0x432aff97, + 0xab9423a7, + 0xfc93a039, + 0x655b59c3, + 0x8f0ccc92, + 0xffeff47d, + 0x85845dd1, + 0x6fa87e4f, + 0xfe2ce6e0, + 0xa3014314, + 0x4e0811a1, + 0xf7537e82, + 0xbd3af235, + 0x2ad7d2bb, + 0xeb86d391, + }, +} + +var program = ` +package md5 + +import ( + "unsafe" + "runtime" +) + +{{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}} + +func block(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 { + aa, bb, cc, dd := a, b, c, d + + // This is a constant condition - it is not evaluated on each iteration. + if runtime.GOARCH == "amd64" || runtime.GOARCH == "386" { + // 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 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 + } + } + + {{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 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 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 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}} + } + {{end}} + + 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 +} +` |