Subversion Repositories lxp32

/*
 * This test calculates a CRC-32 checksum of a small byte array
 * CRC32("123456789")=0xCBF43926
 */

        lc r100, 0x10000000 // test result output pointer
        lc r101, halt
        lc r102, failure
        
        lc r16, 0x10000004 // output pointer
        lc r17, 0xFFFFFFFF // initial CRC value
        lc r18, 0xEDB88320 // polynom
        lc r19, data // input pointer
        
        lc r32, byte_loop
        lc r33, bit_loop
        lc r34, dont_xor
        
        mov r20, 0 // byte counter
        
byte_loop:
        lub r0, r19
        mov r21, 0 // bit counter
        
bit_loop:
        and r1, r0, 1
        and r2, r17, 1
        sru r17, r17, 1
        xor r3, r1, r2
        cjmpe r34, r3, 0
        xor r17, r17, r18
        
dont_xor:
        sru r0, r0, 1
        add r21, r21, 1
        cjmpul r33, r21, 8
        
        add r19, r19, 1
        add r20, r20, 1
        cjmpul r32, r20, 9
        
        not r17, r17
        sw r16, r17
        
        lc r0, 0xCBF43926
        cjmpne r102, r0, r17
        
        sw r100, 1
        jmp r101
        
failure:
        sw r100, 2
        
halt:
        hlt
        jmp r101
        
data:
        .byte "123456789"