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/arch/arm/lib/csumpartialcopygeneric.S

https://bitbucket.org/evzijst/gittest
Assembly | 331 lines | 306 code | 25 blank | 0 comment | 2 complexity | ee62c6be2e160ab11a1a566a3171fb0b MD5 | raw file
  1/*
  2 *  linux/arch/arm/lib/csumpartialcopygeneric.S
  3 *
  4 *  Copyright (C) 1995-2001 Russell King
  5 *
  6 * This program is free software; you can redistribute it and/or modify
  7 * it under the terms of the GNU General Public License version 2 as
  8 * published by the Free Software Foundation.
  9 */
 10
 11/*
 12 * unsigned int
 13 * csum_partial_copy_xxx(const char *src, char *dst, int len, int sum, )
 14 *  r0 = src, r1 = dst, r2 = len, r3 = sum
 15 *  Returns : r0 = checksum
 16 *
 17 * Note that 'tst' and 'teq' preserve the carry flag.
 18 */
 19
 20src	.req	r0
 21dst	.req	r1
 22len	.req	r2
 23sum	.req	r3
 24
 25.zero:		mov	r0, sum
 26		load_regs	ea
 27
 28		/*
 29		 * Align an unaligned destination pointer.  We know that
 30		 * we have >= 8 bytes here, so we don't need to check
 31		 * the length.  Note that the source pointer hasn't been
 32		 * aligned yet.
 33		 */
 34.dst_unaligned:	tst	dst, #1
 35		beq	.dst_16bit
 36
 37		load1b	ip
 38		sub	len, len, #1
 39		adcs	sum, sum, ip, put_byte_1	@ update checksum
 40		strb	ip, [dst], #1
 41		tst	dst, #2
 42		moveq	pc, lr			@ dst is now 32bit aligned
 43
 44.dst_16bit:	load2b	r8, ip
 45		sub	len, len, #2
 46		adcs	sum, sum, r8, put_byte_0
 47		strb	r8, [dst], #1
 48		adcs	sum, sum, ip, put_byte_1
 49		strb	ip, [dst], #1
 50		mov	pc, lr			@ dst is now 32bit aligned
 51
 52		/*
 53		 * Handle 0 to 7 bytes, with any alignment of source and
 54		 * destination pointers.  Note that when we get here, C = 0
 55		 */
 56.less8:		teq	len, #0			@ check for zero count
 57		beq	.zero
 58
 59		/* we must have at least one byte. */
 60		tst	dst, #1			@ dst 16-bit aligned
 61		beq	.less8_aligned
 62
 63		/* Align dst */
 64		load1b	ip
 65		sub	len, len, #1
 66		adcs	sum, sum, ip, put_byte_1	@ update checksum
 67		strb	ip, [dst], #1
 68		tst	len, #6
 69		beq	.less8_byteonly
 70
 711:		load2b	r8, ip
 72		sub	len, len, #2
 73		adcs	sum, sum, r8, put_byte_0
 74		strb	r8, [dst], #1
 75		adcs	sum, sum, ip, put_byte_1
 76		strb	ip, [dst], #1
 77.less8_aligned:	tst	len, #6
 78		bne	1b
 79.less8_byteonly:
 80		tst	len, #1
 81		beq	.done
 82		load1b	r8
 83		adcs	sum, sum, r8, put_byte_0	@ update checksum
 84		strb	r8, [dst], #1
 85		b	.done
 86
 87FN_ENTRY
 88		mov	ip, sp
 89		save_regs
 90		sub	fp, ip, #4
 91
 92		cmp	len, #8			@ Ensure that we have at least
 93		blo	.less8			@ 8 bytes to copy.
 94
 95		adds	sum, sum, #0		@ C = 0
 96		tst	dst, #3			@ Test destination alignment
 97		blne	.dst_unaligned		@ align destination, return here
 98
 99		/*
100		 * Ok, the dst pointer is now 32bit aligned, and we know
101		 * that we must have more than 4 bytes to copy.  Note
102		 * that C contains the carry from the dst alignment above.
103		 */
104
105		tst	src, #3			@ Test source alignment
106		bne	.src_not_aligned
107
108		/* Routine for src & dst aligned */
109
110		bics	ip, len, #15
111		beq	2f
112
1131:		load4l	r4, r5, r6, r7
114		stmia	dst!, {r4, r5, r6, r7}
115		adcs	sum, sum, r4
116		adcs	sum, sum, r5
117		adcs	sum, sum, r6
118		adcs	sum, sum, r7
119		sub	ip, ip, #16
120		teq	ip, #0
121		bne	1b
122
1232:		ands	ip, len, #12
124		beq	4f
125		tst	ip, #8
126		beq	3f
127		load2l	r4, r5
128		stmia	dst!, {r4, r5}
129		adcs	sum, sum, r4
130		adcs	sum, sum, r5
131		tst	ip, #4
132		beq	4f
133
1343:		load1l	r4
135		str	r4, [dst], #4
136		adcs	sum, sum, r4
137
1384:		ands	len, len, #3
139		beq	.done
140		load1l	r4
141		tst	len, #2
142		mov	r5, r4, get_byte_0
143		beq	.exit
144		adcs	sum, sum, r4, push #16
145		strb	r5, [dst], #1
146		mov	r5, r4, get_byte_1
147		strb	r5, [dst], #1
148		mov	r5, r4, get_byte_2
149.exit:		tst	len, #1
150		strneb	r5, [dst], #1
151		andne	r5, r5, #255
152		adcnes	sum, sum, r5, put_byte_0
153
154		/*
155		 * If the dst pointer was not 16-bit aligned, we
156		 * need to rotate the checksum here to get around
157		 * the inefficient byte manipulations in the
158		 * architecture independent code.
159		 */
160.done:		adc	r0, sum, #0
161		ldr	sum, [sp, #0]		@ dst
162		tst	sum, #1
163		movne	r0, r0, ror #8
164		load_regs	ea
165
166.src_not_aligned:
167		adc	sum, sum, #0		@ include C from dst alignment
168		and	ip, src, #3
169		bic	src, src, #3
170		load1l	r5
171		cmp	ip, #2
172		beq	.src2_aligned
173		bhi	.src3_aligned
174		mov	r4, r5, pull #8		@ C = 0
175		bics	ip, len, #15
176		beq	2f
1771:		load4l	r5, r6, r7, r8
178		orr	r4, r4, r5, push #24
179		mov	r5, r5, pull #8
180		orr	r5, r5, r6, push #24
181		mov	r6, r6, pull #8
182		orr	r6, r6, r7, push #24
183		mov	r7, r7, pull #8
184		orr	r7, r7, r8, push #24
185		stmia	dst!, {r4, r5, r6, r7}
186		adcs	sum, sum, r4
187		adcs	sum, sum, r5
188		adcs	sum, sum, r6
189		adcs	sum, sum, r7
190		mov	r4, r8, pull #8
191		sub	ip, ip, #16
192		teq	ip, #0
193		bne	1b
1942:		ands	ip, len, #12
195		beq	4f
196		tst	ip, #8
197		beq	3f
198		load2l	r5, r6
199		orr	r4, r4, r5, push #24
200		mov	r5, r5, pull #8
201		orr	r5, r5, r6, push #24
202		stmia	dst!, {r4, r5}
203		adcs	sum, sum, r4
204		adcs	sum, sum, r5
205		mov	r4, r6, pull #8
206		tst	ip, #4
207		beq	4f
2083:		load1l	r5
209		orr	r4, r4, r5, push #24
210		str	r4, [dst], #4
211		adcs	sum, sum, r4
212		mov	r4, r5, pull #8
2134:		ands	len, len, #3
214		beq	.done
215		mov	r5, r4, get_byte_0
216		tst	len, #2
217		beq	.exit
218		adcs	sum, sum, r4, push #16
219		strb	r5, [dst], #1
220		mov	r5, r4, get_byte_1
221		strb	r5, [dst], #1
222		mov	r5, r4, get_byte_2
223		b	.exit
224
225.src2_aligned:	mov	r4, r5, pull #16
226		adds	sum, sum, #0
227		bics	ip, len, #15
228		beq	2f
2291:		load4l	r5, r6, r7, r8
230		orr	r4, r4, r5, push #16
231		mov	r5, r5, pull #16
232		orr	r5, r5, r6, push #16
233		mov	r6, r6, pull #16
234		orr	r6, r6, r7, push #16
235		mov	r7, r7, pull #16
236		orr	r7, r7, r8, push #16
237		stmia	dst!, {r4, r5, r6, r7}
238		adcs	sum, sum, r4
239		adcs	sum, sum, r5
240		adcs	sum, sum, r6
241		adcs	sum, sum, r7
242		mov	r4, r8, pull #16
243		sub	ip, ip, #16
244		teq	ip, #0
245		bne	1b
2462:		ands	ip, len, #12
247		beq	4f
248		tst	ip, #8
249		beq	3f
250		load2l	r5, r6
251		orr	r4, r4, r5, push #16
252		mov	r5, r5, pull #16
253		orr	r5, r5, r6, push #16
254		stmia	dst!, {r4, r5}
255		adcs	sum, sum, r4
256		adcs	sum, sum, r5
257		mov	r4, r6, pull #16
258		tst	ip, #4
259		beq	4f
2603:		load1l	r5
261		orr	r4, r4, r5, push #16
262		str	r4, [dst], #4
263		adcs	sum, sum, r4
264		mov	r4, r5, pull #16
2654:		ands	len, len, #3
266		beq	.done
267		mov	r5, r4, get_byte_0
268		tst	len, #2
269		beq	.exit
270		adcs	sum, sum, r4
271		strb	r5, [dst], #1
272		mov	r5, r4, get_byte_1
273		strb	r5, [dst], #1
274		tst	len, #1
275		beq	.done
276		load1b	r5
277		b	.exit
278
279.src3_aligned:	mov	r4, r5, pull #24
280		adds	sum, sum, #0
281		bics	ip, len, #15
282		beq	2f
2831:		load4l	r5, r6, r7, r8
284		orr	r4, r4, r5, push #8
285		mov	r5, r5, pull #24
286		orr	r5, r5, r6, push #8
287		mov	r6, r6, pull #24
288		orr	r6, r6, r7, push #8
289		mov	r7, r7, pull #24
290		orr	r7, r7, r8, push #8
291		stmia	dst!, {r4, r5, r6, r7}
292		adcs	sum, sum, r4
293		adcs	sum, sum, r5
294		adcs	sum, sum, r6
295		adcs	sum, sum, r7
296		mov	r4, r8, pull #24
297		sub	ip, ip, #16
298		teq	ip, #0
299		bne	1b
3002:		ands	ip, len, #12
301		beq	4f
302		tst	ip, #8
303		beq	3f
304		load2l	r5, r6
305		orr	r4, r4, r5, push #8
306		mov	r5, r5, pull #24
307		orr	r5, r5, r6, push #8
308		stmia	dst!, {r4, r5}
309		adcs	sum, sum, r4
310		adcs	sum, sum, r5
311		mov	r4, r6, pull #24
312		tst	ip, #4
313		beq	4f
3143:		load1l	r5
315		orr	r4, r4, r5, push #8
316		str	r4, [dst], #4
317		adcs	sum, sum, r4
318		mov	r4, r5, pull #24
3194:		ands	len, len, #3
320		beq	.done
321		mov	r5, r4, get_byte_0
322		tst	len, #2
323		beq	.exit
324		strb	r5, [dst], #1
325		adcs	sum, sum, r4
326		load1l	r4
327		mov	r5, r4, get_byte_0
328		strb	r5, [dst], #1
329		adcs	sum, sum, r4, push #24
330		mov	r5, r4, get_byte_1
331		b	.exit