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gerrit-public.fairphone.software / kernel / msm-4.19 / e0b2f8cff15b2d20a427c381247a8ff6bb28d21e / . / arch / cris / arch-v32 / lib / checksum.S
blob: 4a72a94a49ad6d5a60718e6fc19eec59bc268fd1 [file] [log] [blame]
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]1/*
2 * A fast checksum routine using movem
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]3 * Copyright (c) 1998-2007 Axis Communications AB
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]4 *
5 * csum_partial(const unsigned char * buff, int len, unsigned int sum)
6 */
7
8 .globl csum_partial
Jesper Nilsson3a381252010-08-03 16:16:45 +0200[diff] [blame]9 .type csum_partial,@function
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]10csum_partial:
11
12 ;; r10 - src
13 ;; r11 - length
14 ;; r12 - checksum
15
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]16 ;; Optimized for large packets
17 subq 10*4, $r11
18 blt _word_loop
19 move.d $r11, $acr
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]20
21 subq 9*4,$sp
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]22 clearf c
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]23 movem $r8,[$sp]
24
25 ;; do a movem checksum
26
27_mloop: movem [$r10+],$r9 ; read 10 longwords
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]28 ;; Loop count without touching the c flag.
29 addoq -10*4, $acr, $acr
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]30 ;; perform dword checksumming on the 10 longwords
31
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]32 addc $r0,$r12
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]33 addc $r1,$r12
34 addc $r2,$r12
35 addc $r3,$r12
36 addc $r4,$r12
37 addc $r5,$r12
38 addc $r6,$r12
39 addc $r7,$r12
40 addc $r8,$r12
41 addc $r9,$r12
42
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]43 ;; test $acr without trashing carry.
44 move.d $acr, $acr
45 bpl _mloop
46 ;; r11 <= acr is not really needed in the mloop, just using the dslot
47 ;; to prepare for what is needed after mloop.
48 move.d $acr, $r11
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]49
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]50 ;; fold the last carry into r13
51 addc 0, $r12
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]52 movem [$sp+],$r8 ; restore regs
53
54_word_loop:
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]55 addq 10*4,$r11 ; compensate for last loop underflowing length
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]56
57 moveq -1,$r9 ; put 0xffff in r9, faster than move.d 0xffff,r9
58 lsrq 16,$r9
59
60 move.d $r12,$r13
61 lsrq 16,$r13 ; r13 = checksum >> 16
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]62 and.d $r9,$r12 ; checksum = checksum & 0xffff
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]63
64_no_fold:
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]65 subq 2,$r11
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]66 blt _no_words
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]67 add.d $r13,$r12 ; checksum += r13
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]68
69 ;; checksum the rest of the words
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]70_wloop: subq 2,$r11
71 bge _wloop
72 addu.w [$r10+],$r12
73
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]74_no_words:
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]75 addq 2,$r11
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]76 ;; see if we have one odd byte more
Jesper Nilsson41f94122008-01-25 17:54:14 +0100[diff] [blame]77 bne _do_byte
Mikael Starvik51533b62005-07-27 11:44:44 -0700[diff] [blame]78 nop
79 ret
80 move.d $r12,$r10
81
82_do_byte:
83 ;; copy and checksum the last byte
84 addu.b [$r10],$r12
85 ret
86 move.d $r12,$r10
Jesper Nilsson3a381252010-08-03 16:16:45 +0200[diff] [blame]87
88 .size csum_partial, .-csum_partial