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d2912cb1 | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
1da177e4 LT |
2 | /* |
3 | * linux/arch/arm/lib/csumpartial.S | |
4 | * | |
5 | * Copyright (C) 1995-1998 Russell King | |
1da177e4 LT |
6 | */ |
7 | #include <linux/linkage.h> | |
8 | #include <asm/assembler.h> | |
9 | ||
10 | .text | |
11 | ||
12 | /* | |
13 | * Function: __u32 csum_partial(const char *src, int len, __u32 sum) | |
14 | * Params : r0 = buffer, r1 = len, r2 = checksum | |
15 | * Returns : r0 = new checksum | |
16 | */ | |
17 | ||
18 | buf .req r0 | |
19 | len .req r1 | |
20 | sum .req r2 | |
21 | td0 .req r3 | |
22 | td1 .req r4 @ save before use | |
23 | td2 .req r5 @ save before use | |
24 | td3 .req lr | |
25 | ||
8adbb371 | 26 | .Lzero: mov r0, sum |
1da177e4 LT |
27 | add sp, sp, #4 |
28 | ldr pc, [sp], #4 | |
29 | ||
30 | /* | |
31 | * Handle 0 to 7 bytes, with any alignment of source and | |
32 | * destination pointers. Note that when we get here, C = 0 | |
33 | */ | |
8adbb371 NP |
34 | .Lless8: teq len, #0 @ check for zero count |
35 | beq .Lzero | |
1da177e4 LT |
36 | |
37 | /* we must have at least one byte. */ | |
38 | tst buf, #1 @ odd address? | |
af36bef0 | 39 | movne sum, sum, ror #8 |
e44fc388 | 40 | ldrbne td0, [buf], #1 |
1da177e4 | 41 | subne len, len, #1 |
e44fc388 | 42 | adcsne sum, sum, td0, put_byte_1 |
1da177e4 | 43 | |
8adbb371 NP |
44 | .Lless4: tst len, #6 |
45 | beq .Lless8_byte | |
1da177e4 LT |
46 | |
47 | /* we are now half-word aligned */ | |
48 | ||
8adbb371 | 49 | .Lless8_wordlp: |
1da177e4 LT |
50 | #if __LINUX_ARM_ARCH__ >= 4 |
51 | ldrh td0, [buf], #2 | |
52 | sub len, len, #2 | |
53 | #else | |
54 | ldrb td0, [buf], #1 | |
55 | ldrb td3, [buf], #1 | |
56 | sub len, len, #2 | |
57 | #ifndef __ARMEB__ | |
58 | orr td0, td0, td3, lsl #8 | |
59 | #else | |
60 | orr td0, td3, td0, lsl #8 | |
61 | #endif | |
62 | #endif | |
63 | adcs sum, sum, td0 | |
64 | tst len, #6 | |
8adbb371 | 65 | bne .Lless8_wordlp |
1da177e4 | 66 | |
8adbb371 | 67 | .Lless8_byte: tst len, #1 @ odd number of bytes |
e44fc388 SA |
68 | ldrbne td0, [buf], #1 @ include last byte |
69 | adcsne sum, sum, td0, put_byte_0 @ update checksum | |
1da177e4 | 70 | |
8adbb371 | 71 | .Ldone: adc r0, sum, #0 @ collect up the last carry |
1da177e4 LT |
72 | ldr td0, [sp], #4 |
73 | tst td0, #1 @ check buffer alignment | |
74 | movne r0, r0, ror #8 @ rotate checksum by 8 bits | |
75 | ldr pc, [sp], #4 @ return | |
76 | ||
8adbb371 | 77 | .Lnot_aligned: tst buf, #1 @ odd address |
e44fc388 | 78 | ldrbne td0, [buf], #1 @ make even |
1da177e4 | 79 | subne len, len, #1 |
e44fc388 | 80 | adcsne sum, sum, td0, put_byte_1 @ update checksum |
1da177e4 LT |
81 | |
82 | tst buf, #2 @ 32-bit aligned? | |
83 | #if __LINUX_ARM_ARCH__ >= 4 | |
e44fc388 | 84 | ldrhne td0, [buf], #2 @ make 32-bit aligned |
1da177e4 LT |
85 | subne len, len, #2 |
86 | #else | |
e44fc388 SA |
87 | ldrbne td0, [buf], #1 |
88 | ldrbne ip, [buf], #1 | |
1da177e4 LT |
89 | subne len, len, #2 |
90 | #ifndef __ARMEB__ | |
91 | orrne td0, td0, ip, lsl #8 | |
92 | #else | |
93 | orrne td0, ip, td0, lsl #8 | |
94 | #endif | |
95 | #endif | |
e44fc388 | 96 | adcsne sum, sum, td0 @ update checksum |
6ebbf2ce | 97 | ret lr |
1da177e4 LT |
98 | |
99 | ENTRY(csum_partial) | |
100 | stmfd sp!, {buf, lr} | |
101 | cmp len, #8 @ Ensure that we have at least | |
8adbb371 | 102 | blo .Lless8 @ 8 bytes to copy. |
1da177e4 | 103 | |
af36bef0 RK |
104 | tst buf, #1 |
105 | movne sum, sum, ror #8 | |
106 | ||
1da177e4 LT |
107 | adds sum, sum, #0 @ C = 0 |
108 | tst buf, #3 @ Test destination alignment | |
8adbb371 | 109 | blne .Lnot_aligned @ align destination, return here |
1da177e4 LT |
110 | |
111 | 1: bics ip, len, #31 | |
112 | beq 3f | |
113 | ||
114 | stmfd sp!, {r4 - r5} | |
115 | 2: ldmia buf!, {td0, td1, td2, td3} | |
116 | adcs sum, sum, td0 | |
117 | adcs sum, sum, td1 | |
118 | adcs sum, sum, td2 | |
119 | adcs sum, sum, td3 | |
120 | ldmia buf!, {td0, td1, td2, td3} | |
121 | adcs sum, sum, td0 | |
122 | adcs sum, sum, td1 | |
123 | adcs sum, sum, td2 | |
124 | adcs sum, sum, td3 | |
125 | sub ip, ip, #32 | |
126 | teq ip, #0 | |
127 | bne 2b | |
128 | ldmfd sp!, {r4 - r5} | |
129 | ||
130 | 3: tst len, #0x1c @ should not change C | |
8adbb371 | 131 | beq .Lless4 |
1da177e4 LT |
132 | |
133 | 4: ldr td0, [buf], #4 | |
134 | sub len, len, #4 | |
135 | adcs sum, sum, td0 | |
136 | tst len, #0x1c | |
137 | bne 4b | |
8adbb371 | 138 | b .Lless4 |
93ed3970 | 139 | ENDPROC(csum_partial) |