projects / apple / xnu.git / blame
| Commit | Line | Data |
|---|---|---|
| 1c79356b A |
1 | /* |
| 2 | * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. | |
| 3 | * | |
| 4 | * @APPLE_LICENSE_HEADER_START@ | |
| 5 | * | |
| e5568f75 A |
6 | * The contents of this file constitute Original Code as defined in and |
| 7 | * are subject to the Apple Public Source License Version 1.1 (the | |
| 8 | * "License"). You may not use this file except in compliance with the | |
| 9 | * License. Please obtain a copy of the License at | |
| 10 | * http://www.apple.com/publicsource and read it before using this file. | |
| 1c79356b | 11 | * |
| e5568f75 A |
12 | * This Original Code and all software distributed under the License are |
| 13 | * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER | |
| 1c79356b A |
14 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
| 15 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, | |
| e5568f75 A |
16 | * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the |
| 17 | * License for the specific language governing rights and limitations | |
| 18 | * under the License. | |
| 1c79356b A |
19 | * |
| 20 | * @APPLE_LICENSE_HEADER_END@ | |
| 21 | */ | |
| 22 | #define STANDALONE 0 | |
| 23 | ||
| 24 | #if STANDALONE | |
| 25 | #include "asm.h" | |
| 26 | #include "assym.h" | |
| 27 | #include "proc_reg.h" /* For CACHE_LINE_SIZE */ | |
| 28 | ||
| 29 | #else | |
| 30 | ||
| 31 | #include <mach/ppc/asm.h> | |
| 32 | #if 0 | |
| 33 | /* #include <assym.h> */ | |
| 34 | #include <ppc/proc_reg.h> /* For CACHE_LINE_SIZE */ | |
| 35 | #endif 0 | |
| 36 | #endif | |
| 37 | ||
| 38 | /* | |
| 39 | * Reg 3 - Pointer to data | |
| 40 | * Reg 4 - Length of data | |
| 41 | * Reg 5 - Accumulated sum value | |
| 42 | * Reg 6 - Starting on odd boundary flag (relative to byte 0 of the checksumed data) | |
| 43 | */ | |
| 44 | ||
| 45 | ENTRY(xsum_assym, TAG_NO_FRAME_USED) | |
| 46 | ||
| 47 | mr r11, r6 ; Swapped flag | |
| 48 | addi r8, 0, 0 | |
| 49 | addi r10, 0, 0x1f | |
| 50 | addi r7, 0, 1 | |
| 51 | addic r7, r7, 0 ; This clears the carry bit! | |
| 52 | mr r12, r5 ; Save the passed-in checksum value | |
| 53 | ||
| 54 | /* | |
| 55 | * Sum bytes before cache line boundary | |
| 56 | */ | |
| 57 | ||
| 58 | cmpi cr0,0,r4,0 ; Check for length of 0 | |
| 59 | beq Lleftovers | |
| 60 | ||
| 61 | and. r9, r3, r10 | |
| 62 | beq Laligned32 ; 32 byte aligned | |
| 63 | ||
| 64 | andi. r9, r3, 0x3 | |
| 65 | beq Laligned4 | |
| 66 | ||
| 67 | andi. r9, r3, 0x1 | |
| 68 | beq Laligned2 ; 2 byte aligned | |
| 69 | ||
| 70 | addi r11, 0, 1 ; swap bytes at end | |
| 71 | lbz r8, 0(r3) | |
| 72 | add r3, r3, r7 | |
| 73 | subf. r4, r7, r4 | |
| 74 | beq Ldone | |
| 75 | ||
| 76 | Laligned2: | |
| 77 | cmpi cr0,0,r4,2 ; If remaining length is less than two - go to wrap-up | |
| 78 | blt Lleftovers | |
| 79 | andi. r9, r3, 0x3 ; If aligned on a 4-byte boundary, go to that code | |
| 80 | beq Laligned4 | |
| 81 | lhz r5, 0(r3) ; Load and add a halfword to the checksum | |
| 82 | adde r8, r8, r5 | |
| 83 | slwi r7, r7, 1 | |
| 84 | add r3, r3, r7 | |
| 85 | subf. r4, r7, r4 | |
| 86 | beq Ldone | |
| 87 | ||
| 88 | ||
| 89 | /* | |
| 90 | Add longwords up to the 32 byte boundary | |
| 91 | */ | |
| 92 | ||
| 93 | Laligned4: | |
| 94 | addi r7, 0, 4 | |
| 95 | Lloop4: | |
| 96 | cmpi cr0,0,r4,4 | |
| 97 | blt Lleftovers | |
| 98 | and. r9, r3, r10 | |
| 99 | beq Laligned32 | |
| 100 | lwz r5, 0(r3) | |
| 101 | adde r8, r8, r5 | |
| 102 | add r3, r3, r7 | |
| 103 | subf. r4, r7, r4 | |
| 104 | bne Lloop4 | |
| 105 | b Ldone | |
| 106 | ||
| 107 | ||
| 108 | /* | |
| 109 | We're aligned on a 32 byte boundary now - add 8 longwords to checksum | |
| 110 | until the remaining length is less than 32 | |
| 111 | */ | |
| 112 | Laligned32: | |
| 113 | andis. r6, r4, 0xffff | |
| 114 | bne Lmainloop | |
| 115 | andi. r6, r4, 0xffe0 | |
| 116 | beq Lleftovers | |
| 117 | ||
| 118 | Lmainloop: | |
| 119 | addi r9, 0, 64 | |
| 120 | addi r10, 0, 32 | |
| 121 | cmpi cr0,0,r4,64 | |
| 122 | blt Lnopretouch | |
| 123 | dcbt r3, r10 ; Touch one cache-line ahead | |
| 124 | Lnopretouch: | |
| 125 | lwz r5, 0(r3) | |
| 126 | ||
| 127 | /* | |
| 128 | * This is the main meat of the checksum. I attempted to arrange this code | |
| 129 | * such that the processor would execute as many instructions as possible | |
| 130 | * in parallel. | |
| 131 | */ | |
| 132 | ||
| 133 | Lloop: | |
| 134 | cmpi cr0,0,r4,96 | |
| 135 | blt Lnotouch | |
| 136 | dcbt r3, r9 ; Touch two cache lines ahead | |
| 137 | Lnotouch: | |
| 138 | adde r8, r8, r5 | |
| 139 | lwz r5, 4(r3) | |
| 140 | lwz r6, 8(r3) | |
| 141 | lwz r7, 12(r3) | |
| 142 | adde r8, r8, r5 | |
| 143 | lwz r5, 16(r3) | |
| 144 | adde r8, r8, r6 | |
| 145 | lwz r6, 20(r3) | |
| 146 | adde r8, r8, r7 | |
| 147 | lwz r7, 24(r3) | |
| 148 | adde r8, r8, r5 | |
| 149 | lwz r5, 28(r3) | |
| 150 | add r3, r3, r10 | |
| 151 | adde r8, r8, r6 | |
| 152 | adde r8, r8, r7 | |
| 153 | adde r8, r8, r5 | |
| 154 | subf r4, r10, r4 | |
| 155 | andi. r6, r4, 0xffe0 | |
| 156 | beq Lleftovers | |
| 157 | lwz r5, 0(r3) | |
| 158 | b Lloop | |
| 159 | ||
| 160 | /* | |
| 161 | * Handle whatever bytes are left | |
| 162 | */ | |
| 163 | ||
| 164 | Lleftovers: | |
| 165 | /* | |
| 166 | * Handle leftover bytes | |
| 167 | */ | |
| 168 | cmpi cr0,0,r4,0 | |
| 169 | beq Ldone | |
| 170 | ||
| 171 | addi r7, 0, 1 | |
| 172 | addi r10, 0, 0x7ffc | |
| 173 | ||
| 174 | and. r9, r4, r10 | |
| 175 | bne Lfourormore | |
| 176 | srw r10, r10, r7 | |
| 177 | and. r9, r4, r10 | |
| 178 | bne Ltwoormore | |
| 179 | b Loneleft | |
| 180 | ||
| 181 | Lfourormore: | |
| 182 | addi r10, 0, 4 | |
| 183 | ||
| 184 | Lfourloop: | |
| 185 | lwz r5, 0(r3) | |
| 186 | adde r8, r8, r5 | |
| 187 | add r3, r3, r10 | |
| 188 | subf r4, r10, r4 | |
| 189 | andi. r6, r4, 0xfffc | |
| 190 | bne Lfourloop | |
| 191 | ||
| 192 | Ltwoormore: | |
| 193 | andi. r6, r4, 0xfffe | |
| 194 | beq Loneleft | |
| 195 | lhz r5, 0(r3) | |
| 196 | adde r8, r8, r5 | |
| 197 | addi r3, r3, 2 | |
| 198 | subi r4, r4, 2 | |
| 199 | ||
| 200 | Loneleft: | |
| 201 | cmpi cr0,0,r4,0 | |
| 202 | beq Ldone | |
| 203 | lbz r5, 0(r3) | |
| 204 | slwi r5, r5, 8 | |
| 205 | adde r8, r8, r5 | |
| 206 | ||
| 207 | /* | |
| 208 | * Wrap the longword around, adding the two 16-bit portions | |
| 209 | * to each other along with any previous and subsequent carries. | |
| 210 | */ | |
| 211 | Ldone: | |
| 212 | addze r8, r8 ; Add the carry | |
| 213 | addze r8, r8 ; Add the carry again (the last add may have carried) | |
| 214 | andis. r6, r8, 0xffff ; Stuff r6 with the high order 16 bits of sum word | |
| 215 | srwi r6, r6, 16 ; Shift it to the low order word | |
| 216 | andi. r8, r8, 0xffff ; Zero out the high order word | |
| 217 | add r8, r8, r6 ; Add the two halves | |
| 218 | ||
| 219 | andis. r6, r8, 0xffff ; Do the above again in case we carried into the | |
| 220 | srwi r6, r6, 16 ; high order word with the last add. | |
| 221 | andi. r8, r8, 0xffff | |
| 222 | add r3, r8, r6 | |
| 223 | ||
| 224 | cmpi cr0,0,r11,0 ; Check to see if we need to swap the bytes | |
| 225 | beq Ldontswap | |
| 226 | ||
| 227 | /* | |
| 228 | * Our buffer began on an odd boundary, so we need to swap | |
| 229 | * the checksum bytes. | |
| 230 | */ | |
| 231 | slwi r8, r3, 8 ; shift byte 0 to byte 1 | |
| 232 | clrlwi r8, r8, 16 ; Clear top 16 bits | |
| 233 | srwi r3, r3, 8 ; shift byte 1 to byte 0 | |
| 234 | or r3, r8, r3 ; or them | |
| 235 | ||
| 236 | Ldontswap: | |
| 237 | add r3, r3, r12 ; Add in the passed-in checksum | |
| 238 | andis. r6, r3, 0xffff ; Wrap and add any carries into the top 16 bits | |
| 239 | srwi r6, r6, 16 | |
| 240 | andi. r3, r3, 0xffff | |
| 241 | add r3, r3, r6 | |
| 242 | ||
| 243 | andis. r6, r3, 0xffff ; Do the above again in case we carried into the | |
| 244 | srwi r6, r6, 16 ; high order word with the last add. | |
| 245 | andi. r3, r3, 0xffff | |
| 246 | add r3, r3, r6 | |
| 247 | blr | |
| 248 | ||
| 249 |