Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/arm/arm/in_cksum_arm.S
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1 /* $NetBSD: in_cksum_arm.S,v 1.2 2003/09/23 10:01:36 scw Exp $ */ 2 3 /*- 4 * Copyright 2003 Wasabi Systems, Inc. 5 * All rights reserved. 6 * 7 * Written by Steve C. Woodford for Wasabi Systems, Inc. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed for the NetBSD Project by 20 * Wasabi Systems, Inc. 21 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 22 * or promote products derived from this software without specific prior 23 * written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 29 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 * POSSIBILITY OF SUCH DAMAGE. 36 * 37 */ 38 39 /* 40 * Hand-optimised in_cksum() and in4_cksum() implementations for ARM/armv5e 41 */ 42 43 #include "opt_inet.h" 44 45 #include <machine/asm.h> 46 #include "assym.inc" 47 __FBSDID("$FreeBSD$"); 48 49 .syntax unified 50 /* 51 * int in_cksum(struct mbuf *m, int len) 52 * 53 * Entry: 54 * r0 m 55 * r1 len 56 * 57 * NOTE: Assumes 'm' is *never* NULL. 58 */ 59 /* LINTSTUB: Func: int in_cksum(struct mbuf *, int) */ 60 ENTRY(in_cksum) 61 stmfd sp!, {r4-r11,lr} 62 mov r8, #0x00 63 mov r9, r1 64 mov r10, #0x00 65 mov ip, r0 66 67 .Lin_cksum_loop: 68 ldr r1, [ip, #(M_LEN)] 69 ldr r0, [ip, #(M_DATA)] 70 ldr ip, [ip, #(M_NEXT)] 71 .Lin_cksum_entry4: 72 cmp r9, r1 73 movlt r1, r9 74 sub r9, r9, r1 75 eor r11, r10, r0 76 add r10, r10, r1 77 adds r2, r1, #0x00 78 blne _ASM_LABEL(L_cksumdata) 79 tst r11, #0x01 80 movne r2, r2, ror #8 81 adds r8, r8, r2 82 adc r8, r8, #0x00 83 cmp ip, #0x00 84 bne .Lin_cksum_loop 85 86 mov r1, #0xff 87 orr r1, r1, #0xff00 88 and r0, r8, r1 89 add r0, r0, r8, lsr #16 90 add r0, r0, r0, lsr #16 91 and r0, r0, r1 92 eor r0, r0, r1 93 ldmfd sp!, {r4-r11,pc} 94 END(in_cksum) 95 96 ENTRY(do_cksum) 97 stmfd sp!, {r4-r7, lr} 98 bl L_cksumdata 99 mov r0, r2 100 ldmfd sp!, {r4-r7, pc} 101 END(do_cksum) 102 103 /* 104 * The main in*_cksum() workhorse... 105 * 106 * Entry parameters: 107 * r0 Pointer to buffer 108 * r1 Buffer length 109 * lr Return address 110 * 111 * Returns: 112 * r2 Accumulated 32-bit sum 113 * 114 * Clobbers: 115 * r0-r7 116 */ 117 /* LINTSTUB: Ignore */ 118 ASENTRY_NP(L_cksumdata) 119 pld [r0] /* Pre-fetch the start of the buffer */ 120 mov r2, #0 121 122 /* We first have to word-align the buffer. */ 123 ands r7, r0, #0x03 124 beq .Lcksumdata_wordaligned 125 rsb r7, r7, #0x04 126 cmp r1, r7 /* Enough bytes left to make it? */ 127 blt .Lcksumdata_endgame 128 cmp r7, #0x02 129 ldrb r4, [r0], #0x01 /* Fetch 1st byte */ 130 ldrbge r5, [r0], #0x01 /* Fetch 2nd byte */ 131 movlt r5, #0x00 132 ldrbgt r6, [r0], #0x01 /* Fetch 3rd byte */ 133 movle r6, #0x00 134 135 /* Combine the three bytes depending on endianness and alignment */ 136 orreq r2, r4, r5, lsl #8 137 orreq r2, r2, r6, lsl #16 138 orrne r2, r5, r4, lsl #8 139 orrne r2, r2, r6, lsl #24 140 subs r1, r1, r7 /* Update length */ 141 RETeq /* All done? */ 142 143 /* Buffer is now word aligned */ 144 .Lcksumdata_wordaligned: 145 cmp r1, #0x04 /* Less than 4 bytes left? */ 146 blt .Lcksumdata_endgame /* Yup */ 147 148 /* Now quad-align, if necessary */ 149 ands r7, r0, #0x04 150 ldrne r7, [r0], #0x04 151 subne r1, r1, #0x04 152 subs r1, r1, #0x40 153 blt .Lcksumdata_bigloop_end /* Note: C flag clear if branch taken */ 154 155 /* 156 * Buffer is now quad aligned. Sum 64 bytes at a time. 157 * Note: First ldrd is hoisted above the loop, together with 158 * setting r6 to zero to avoid stalling for results in the 159 * loop. (r7 is live, from above). 160 */ 161 ldrd r4, [r0], #0x08 162 mov r6, #0x00 163 .Lcksumdata_bigloop: 164 pld [r0, #0x18] 165 adds r2, r2, r6 166 adcs r2, r2, r7 167 ldrd r6, [r0], #0x08 168 adcs r2, r2, r4 169 adcs r2, r2, r5 170 ldrd r4, [r0], #0x08 171 adcs r2, r2, r6 172 adcs r2, r2, r7 173 ldrd r6, [r0], #0x08 174 adcs r2, r2, r4 175 adcs r2, r2, r5 176 ldrd r4, [r0], #0x08 177 adcs r2, r2, r6 178 adcs r2, r2, r7 179 pld [r0, #0x18] 180 ldrd r6, [r0], #0x08 181 adcs r2, r2, r4 182 adcs r2, r2, r5 183 ldrd r4, [r0], #0x08 184 adcs r2, r2, r6 185 adcs r2, r2, r7 186 ldrd r6, [r0], #0x08 187 adcs r2, r2, r4 188 adcs r2, r2, r5 189 adc r2, r2, #0x00 190 subs r1, r1, #0x40 191 ldrdge r4, [r0], #0x08 192 bge .Lcksumdata_bigloop 193 194 adds r2, r2, r6 /* r6/r7 still need summing */ 195 .Lcksumdata_bigloop_end: 196 adcs r2, r2, r7 197 adc r2, r2, #0x00 198 199 adds r1, r1, #0x40 200 RETeq 201 cmp r1, #0x20 202 203 ldrdge r4, [r0], #0x08 /* Avoid stalling pld and result */ 204 blt .Lcksumdata_less_than_32 205 pld [r0, #0x18] 206 ldrd r6, [r0], #0x08 207 adds r2, r2, r4 208 adcs r2, r2, r5 209 ldrd r4, [r0], #0x08 210 adcs r2, r2, r6 211 adcs r2, r2, r7 212 ldrd r6, [r0], #0x08 213 adcs r2, r2, r4 214 adcs r2, r2, r5 215 adcs r2, r2, r6 /* XXX: Unavoidable result stall */ 216 adcs r2, r2, r7 217 adc r2, r2, #0x00 218 subs r1, r1, #0x20 219 RETeq 220 221 .Lcksumdata_less_than_32: 222 /* There are less than 32 bytes left */ 223 and r3, r1, #0x18 224 rsb r4, r3, #0x18 225 sub r1, r1, r3 226 adds r4, r4, r4, lsr #1 /* Side effect: Clear carry flag */ 227 addne pc, pc, r4 228 nop 229 230 /* 231 * Note: We use ldm here, even on armv5e, since the combined issue/result 232 * latencies for ldm and ldrd are the same. Using ldm avoids needless #ifdefs. 233 */ 234 /* At least 24 bytes remaining... */ 235 ldmia r0!, {r4, r5} 236 adcs r2, r2, r4 237 adcs r2, r2, r5 238 239 /* At least 16 bytes remaining... */ 240 ldmia r0!, {r4, r5} 241 adcs r2, r2, r4 242 adcs r2, r2, r5 243 244 /* At least 8 bytes remaining... */ 245 ldmia r0!, {r4, r5} 246 adcs r2, r2, r4 247 adcs r2, r2, r5 248 249 /* Less than 8 bytes remaining... */ 250 adc r2, r2, #0x00 251 subs r1, r1, #0x04 252 blt .Lcksumdata_lessthan4 253 254 ldr r4, [r0], #0x04 255 sub r1, r1, #0x04 256 adds r2, r2, r4 257 adc r2, r2, #0x00 258 259 /* Deal with < 4 bytes remaining */ 260 .Lcksumdata_lessthan4: 261 adds r1, r1, #0x04 262 RETeq 263 264 /* Deal with 1 to 3 remaining bytes, possibly misaligned */ 265 .Lcksumdata_endgame: 266 ldrb r3, [r0] /* Fetch first byte */ 267 cmp r1, #0x02 268 ldrbge r4, [r0, #0x01] /* Fetch 2nd and 3rd as necessary */ 269 movlt r4, #0x00 270 ldrbgt r5, [r0, #0x02] 271 movle r5, #0x00 272 /* Combine the three bytes depending on endianness and alignment */ 273 tst r0, #0x01 274 orreq r3, r3, r4, lsl #8 275 orreq r3, r3, r5, lsl #16 276 orrne r3, r4, r3, lsl #8 277 orrne r3, r3, r5, lsl #24 278 adds r2, r2, r3 279 adc r2, r2, #0x00 280 RET 281 END(L_cksumdata) 282
Cache object: c35e25446bea7e198f0688e8d1a16fb5
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