diff options
Diffstat (limited to 'utils/rk27utils/rk27load/checksum.c')
-rw-r--r-- | utils/rk27utils/rk27load/checksum.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/utils/rk27utils/rk27load/checksum.c b/utils/rk27utils/rk27load/checksum.c new file mode 100644 index 0000000000..f0fe59350e --- /dev/null +++ b/utils/rk27utils/rk27load/checksum.c | |||
@@ -0,0 +1,35 @@ | |||
1 | #include <stdint.h> | ||
2 | #include "checksum.h" | ||
3 | |||
4 | uint16_t checksum(void *buff, uint32_t size) | ||
5 | { | ||
6 | uint32_t r2 = 0xffff; | ||
7 | uint32_t r3 = 0; | ||
8 | uint32_t i, j; | ||
9 | |||
10 | for (i=0; i<size; i++) { | ||
11 | r3 = 0x80; | ||
12 | for (j=0; j<8; j++) { | ||
13 | if ((r2 & 0x8000) != 0) { | ||
14 | r2 <<= 17; | ||
15 | r2 >>= 16; | ||
16 | r2 ^= 0x1000; | ||
17 | r2 ^= 0x21; | ||
18 | } | ||
19 | else { | ||
20 | r2 <<= 17; | ||
21 | r2 >>= 16; | ||
22 | } | ||
23 | |||
24 | if ((((uint8_t *)buff)[i] & r3) != 0) { | ||
25 | r2 ^= 0x1000; | ||
26 | r2 ^= 0x21; | ||
27 | } | ||
28 | |||
29 | r3 >>= 1; | ||
30 | } | ||
31 | } | ||
32 | |||
33 | return r2 & 0xffff; | ||
34 | } | ||
35 | |||