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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