| title | date | tags |
|---|---|---|
高性能CRC算法 |
2014.08.01 |
算法, C, 数据 |
use table
endian =
0: msb, RefIn = TRUE, RefOut = TRUE Mirror_Poly
1: lsb, RefIn = FALSE, RefOut = FALSE Normal_Poly
refer Wikipedia to add a rule ,for example CRC16 IBM below, uncommant it, and commant the last one. the some examples, if I miss any， pull request is welcome
/* CRC-16 IBM
#define endian16 0
#define Poly16_Normal 0x8005
#define Poly16_Mirror 0xA001
#define Crc16_Init 0x0000
#define Crc16_XorOut 0x0000
*/
CRC8.asm
crc8TableInit: ;output crc table start from sram 0x20, sram 0x0C wil over write
PUSH R3
PUSH R2
MOV R3, #0x00 ;for (i = 0; i<256 ;) {
fori:
LDR R0, R3
JP B8, =foriend
MOV R1, #0x0C ;crc = i
LDR [R1], R3
MOV R2, #0x00 ;for (j = 0; j<8 ;) {
forj:
LDR R0, R2
JP B3, =forjend
PUSH R3
PUSH R2
MOV R1, #0x0C ;C1 = (crc << 1) => R2
LDR R0, [R1]
RSL R0, #1
AND R0, #0xFF
LDR R2, R0
MOV R1, #0x0C ;C2 = ((crc & 0x80) ? Poly : 0) => R3
LDR R0, [R1]
JP B7, =Poly
MOV R3, #0x00
JP A1, =afterPoly
Poly:
MOV R3, #0x07
afterPoly: ;crc = (C1 ^ C2) & 0xFF
LDR R0, R2
XOR R0, R3
AND R0, #0xFF
MOV R1, #0x0C
LDR [R1], R0
POP R2
POP R3
LDR R0, R2 ;j++
ADD R0, #0x01
LDR R2, R0
JP A1, =forj
forjend:
MOV R1, #0x0C ;crc8table[i] = crc
LDR R0, [R1]
PUSH R0
MOV R0, #0x20
ADD R0, R3
LDR R1, R0
POP R0
LDR [R1], R0
LDR R0, R3 ;i++
ADD R0, #0x01
LDR R3, R0
JP A1, =fori
foriend:
POP R2
POP R3
RET
crc8Init: ;output sram 0x0C
PUSH R1
MOV R1, #0x0C
MOV [R1], #0x00
POP R1
RET
crc8Update: ;input 1 byte date R0, output sram 0x0B
PUSH R0
PUSH R1
MOV R1, #0x0C ;*pCrc8 = crc8table[pData[i] ^ *pCrc8];
AND R0, #0xFF
XOR R0, [R1]
ADD R0, #0x20
LDR R1, R0
LDR R0, [R1]
MOV R1, #0x0C
LDR [R1], R0
POP R1
POP R0
RET
crc8Fihshed: ;output SRAM 0x0C
PUSH R0
PUSH R1
MOV R0, #0x00
MOV R1, #0x0C
XOR R0, [R1]
LDR [R1], R0
POP R1
POP R0
RET
CRC32.asm
crc32TableInit: ;output crc table start from sram 0x10, sram 0x0B wil over write
MOV R3, #0x00 ;for (i = 0; ;) {
gennumber:
MOV R1, #0x0B ;c = (unsigned int)i
LDR [R1], R3
MOV R2, #0x00 ;for (j = 0; ;) {
genbit:
PUSH R2
MOV R1, #0x0B ;c' = c
LDR R0, [R1]
LDR R2, R0 ;temp of c'
AND R0, #0x01 ;if ((c' & 1) == 0)
JP Z, =genbit0
JP A1, =genbit1
genbit1: ;c' = 0xedb88320L ^ (c' >> 1)
LDR R0, R2
RSR R0, #0x01
LDR R2, R0
MOV R0, #0x7FFF ;bit0 not save
RSL R0, #0x10
OR R0, #0xFFFF
AND R0, R2
LDR R2, R0
MOV R0, #0xEDB8
RSL R0, #0x10
OR R0, #0x8320
XOR R0, R2
JP A1, =genbitdone
genbit0: ;c' = (c' >> 1)
LDR R0, R2
RSR R0, #0x01
JP A1, =genbitdone
genbitdone:
MOV R1, #0x0B ;c = c'
LDR [R1], R0
POP R2
LDR R0, R2 ;j < 8
XOR R0, #0x07
JP Z, =genNext
LDR R0, R2 ; j++
ADD R0, #0x01
LDR R2, R0
JP A1, =genbit
genNext:
MOV R1, #0x0B ;crc_table[i] = c
LDR R2, [R1]
LDR R0, R3 ;offset at 0x10
ADD R0, #0x10
LDR R1, R0
LDR [R1], R2
LDR R0, R3 ;i < 256;
XOR R0, #0xFF
JP Z, =crc32TableInitDone
LDR R0, R3 ; i++
ADD R0, #0x01
LDR R3, R0
JP A1, =gennumber
crc32TableInitDone:
RET
crc32Init: ;output sram 0x0B
PUSH R1
PUSH R0
MOV R0, #0xFFFF
RSL R0, #0x10
OR R0, #0xFFFF
MOV R1, #0x0B
LDR [R1], R0
POP R0
POP R1
RET
crc32Update: ;input byte date R0, output sram 0x0B
PUSH R3
PUSH R2
PUSH R1
LDR R2, R0
;R0 = (*pCrc32) & 0x000000FF
MOV R1, #0x0B
LDR R0, [R1]
AND R0, #0x000000FF
;R0 = (pData[i]) ^ ((*pCrc32) & 0x000000FF)
XOR R0, R2
;R3 = crc32tab[(pData[i]) ^ (*pCrc32) & 0x000000FF]
ADD R0, #0x10 ;table start address
LDR R1, R0
LDR R3, [R1]
;R0 = (*pCrc32) >> 8
MOV R1, #0x0B
LDR R0, [R1]
RSR R0, #0x08
LDR R2, R0
MOV R0, #0x00FF
RSL R0, #0x10
OR R0, #0xFFFF
AND R0, R2
;Store crc = R0 ^ R3
XOR R0, R3
MOV R1, #0x0B
LDR [R1], R0
POP R1
POP R2
POP R3
RET
crc32Fihshed: ;output SRAM 0x0B
PUSH R1
PUSH R0
MOV R0, #0xFFFF
RSL R0, #0x10
OR R0, #0xFFFF
MOV R1, #0x0B
XOR R0, [R1]
LDR [R1], R0
POP R0
POP R1
RET
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