github.com/4ad/go@v0.0.0-20161219182952-69a12818b605/src/runtime/mkduff.go (about) 1 // Copyright 2015 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // +build ignore 6 7 // runtime·duffzero is a Duff's device for zeroing memory. 8 // The compiler jumps to computed addresses within 9 // the routine to zero chunks of memory. 10 // Do not change duffzero without also 11 // changing clearfat in cmd/?g/ggen.go. 12 13 // runtime·duffcopy is a Duff's device for copying memory. 14 // The compiler jumps to computed addresses within 15 // the routine to copy chunks of memory. 16 // Source and destination must not overlap. 17 // Do not change duffcopy without also 18 // changing blockcopy in cmd/?g/cgen.go. 19 20 // See the zero* and copy* generators below 21 // for architecture-specific comments. 22 23 // mkduff generates duff_*.s. 24 package main 25 26 import ( 27 "bytes" 28 "fmt" 29 "io" 30 "io/ioutil" 31 "log" 32 ) 33 34 func main() { 35 gen("amd64", notags, zeroAMD64, copyAMD64) 36 gen("386", notags, zero386, copy386) 37 gen("arm", notags, zeroARM, copyARM) 38 gen("arm64", notags, zeroARM64, copyARM64) 39 gen("ppc64x", tagsPPC64x, zeroPPC64x, copyPPC64x) 40 gen("mips64x", tagsMIPS64x, zeroMIPS64x, copyMIPS64x) 41 gen("sparc64", notags, zeroSPARC64, copySPARC64) 42 } 43 44 func gen(arch string, tags, zero, copy func(io.Writer)) { 45 var buf bytes.Buffer 46 47 fmt.Fprintln(&buf, "// AUTO-GENERATED by mkduff.go") 48 fmt.Fprintln(&buf, "// Run go generate from src/runtime to update.") 49 fmt.Fprintln(&buf, "// See mkduff.go for comments.") 50 tags(&buf) 51 fmt.Fprintln(&buf, "#include \"textflag.h\"") 52 fmt.Fprintln(&buf) 53 zero(&buf) 54 fmt.Fprintln(&buf) 55 copy(&buf) 56 57 if err := ioutil.WriteFile("duff_"+arch+".s", buf.Bytes(), 0644); err != nil { 58 log.Fatalln(err) 59 } 60 } 61 62 func notags(w io.Writer) { fmt.Fprintln(w) } 63 64 func zeroAMD64(w io.Writer) { 65 // X0: zero 66 // DI: ptr to memory to be zeroed 67 // DI is updated as a side effect. 68 fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $0-0") 69 for i := 0; i < 16; i++ { 70 fmt.Fprintln(w, "\tMOVUPS\tX0,(DI)") 71 fmt.Fprintln(w, "\tMOVUPS\tX0,16(DI)") 72 fmt.Fprintln(w, "\tMOVUPS\tX0,32(DI)") 73 fmt.Fprintln(w, "\tMOVUPS\tX0,48(DI)") 74 fmt.Fprintln(w, "\tADDQ\t$64,DI") 75 fmt.Fprintln(w) 76 } 77 fmt.Fprintln(w, "\tRET") 78 } 79 80 func copyAMD64(w io.Writer) { 81 // SI: ptr to source memory 82 // DI: ptr to destination memory 83 // SI and DI are updated as a side effect. 84 // 85 // This is equivalent to a sequence of MOVSQ but 86 // for some reason that is 3.5x slower than this code. 87 // The STOSQ in duffzero seem fine, though. 88 fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT, $0-0") 89 for i := 0; i < 64; i++ { 90 fmt.Fprintln(w, "\tMOVUPS\t(SI), X0") 91 fmt.Fprintln(w, "\tADDQ\t$16, SI") 92 fmt.Fprintln(w, "\tMOVUPS\tX0, (DI)") 93 fmt.Fprintln(w, "\tADDQ\t$16, DI") 94 fmt.Fprintln(w) 95 } 96 fmt.Fprintln(w, "\tRET") 97 } 98 99 func zero386(w io.Writer) { 100 // AX: zero 101 // DI: ptr to memory to be zeroed 102 // DI is updated as a side effect. 103 fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $0-0") 104 for i := 0; i < 128; i++ { 105 fmt.Fprintln(w, "\tSTOSL") 106 } 107 fmt.Fprintln(w, "\tRET") 108 } 109 110 func copy386(w io.Writer) { 111 // SI: ptr to source memory 112 // DI: ptr to destination memory 113 // SI and DI are updated as a side effect. 114 // 115 // This is equivalent to a sequence of MOVSL but 116 // for some reason MOVSL is really slow. 117 fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT, $0-0") 118 for i := 0; i < 128; i++ { 119 fmt.Fprintln(w, "\tMOVL\t(SI), CX") 120 fmt.Fprintln(w, "\tADDL\t$4, SI") 121 fmt.Fprintln(w, "\tMOVL\tCX, (DI)") 122 fmt.Fprintln(w, "\tADDL\t$4, DI") 123 fmt.Fprintln(w) 124 } 125 fmt.Fprintln(w, "\tRET") 126 } 127 128 func zeroARM(w io.Writer) { 129 // R0: zero 130 // R1: ptr to memory to be zeroed 131 // R1 is updated as a side effect. 132 fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $0-0") 133 for i := 0; i < 128; i++ { 134 fmt.Fprintln(w, "\tMOVW.P\tR0, 4(R1)") 135 } 136 fmt.Fprintln(w, "\tRET") 137 } 138 139 func copyARM(w io.Writer) { 140 // R0: scratch space 141 // R1: ptr to source memory 142 // R2: ptr to destination memory 143 // R1 and R2 are updated as a side effect 144 fmt.Fprintln(w, "TEXT runtime·duffcopy(SB), NOSPLIT, $0-0") 145 for i := 0; i < 128; i++ { 146 fmt.Fprintln(w, "\tMOVW.P\t4(R1), R0") 147 fmt.Fprintln(w, "\tMOVW.P\tR0, 4(R2)") 148 fmt.Fprintln(w) 149 } 150 fmt.Fprintln(w, "\tRET") 151 } 152 153 func zeroARM64(w io.Writer) { 154 // ZR: always zero 155 // R16 (aka REGRT1): ptr to memory to be zeroed - 8 156 // On return, R16 points to the last zeroed dword. 157 fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $-8-0") 158 for i := 0; i < 128; i++ { 159 fmt.Fprintln(w, "\tMOVD.W\tZR, 8(R16)") 160 } 161 fmt.Fprintln(w, "\tRET") 162 } 163 164 func copyARM64(w io.Writer) { 165 fmt.Fprintln(w, "// TODO: Implement runtime·duffcopy.") 166 } 167 168 func tagsPPC64x(w io.Writer) { 169 fmt.Fprintln(w) 170 fmt.Fprintln(w, "// +build ppc64 ppc64le") 171 fmt.Fprintln(w) 172 } 173 174 func zeroPPC64x(w io.Writer) { 175 // R0: always zero 176 // R3 (aka REGRT1): ptr to memory to be zeroed - 8 177 // On return, R3 points to the last zeroed dword. 178 fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT|NOFRAME, $0-0") 179 for i := 0; i < 128; i++ { 180 fmt.Fprintln(w, "\tMOVDU\tR0, 8(R3)") 181 } 182 fmt.Fprintln(w, "\tRET") 183 } 184 185 func copyPPC64x(w io.Writer) { 186 fmt.Fprintln(w, "// TODO: Implement runtime·duffcopy.") 187 } 188 189 func zeroSPARC64(w io.Writer) { 190 // ZR (aka G0): always zero 191 // RT1 (aka G1): ptr to memory to be zeroed - 8 192 // On return, RT1 points to the last zeroed dword. 193 fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT|NOFRAME, $0-0") 194 for i := 0; i < 128; i++ { 195 fmt.Fprintln(w, "\tMOVD\tZR, 8(RT1)") 196 fmt.Fprintln(w, "\tADD\t$8, RT1") 197 } 198 fmt.Fprintln(w, "\tRET") 199 } 200 201 func copySPARC64(w io.Writer) { 202 fmt.Fprintln(w, "// TODO: Implement runtime·duffcopy.") 203 } 204 205 func tagsMIPS64x(w io.Writer) { 206 fmt.Fprintln(w) 207 fmt.Fprintln(w, "// +build mips64 mips64le") 208 fmt.Fprintln(w) 209 } 210 211 func zeroMIPS64x(w io.Writer) { 212 // R0: always zero 213 // R1 (aka REGRT1): ptr to memory to be zeroed - 8 214 // On return, R1 points to the last zeroed dword. 215 fmt.Fprintln(w, "TEXT runtime·duffzero(SB), NOSPLIT, $-8-0") 216 for i := 0; i < 128; i++ { 217 fmt.Fprintln(w, "\tMOVV\tR0, 8(R1)") 218 fmt.Fprintln(w, "\tADDV\t$8, R1") 219 } 220 fmt.Fprintln(w, "\tRET") 221 } 222 223 func copyMIPS64x(w io.Writer) { 224 fmt.Fprintln(w, "// TODO: Implement runtime·duffcopy.") 225 }