gistfile1.txt

mcp:                                    @ @mcp
        .fnstart
@ BB#0:
        .save   {r4, r5, r6, lr}
        push    {r4, r5, r6, lr}
        mov     r2, r1
        ldrb    r12, [r2, #4]!
        ldrb    lr, [r1]
        ldrb    r6, [r2, #2]
        ldrb    r2, [r2, #3]
        ldrb    r3, [r1, #1]
        ldrb    r4, [r1, #2]
        ldrb    r5, [r1, #3]
        ldrb    r1, [r1, #5]
        strb    r1, [r0, #5]
        strb    r5, [r0, #3]
        strb    r4, [r0, #2]
        orr     r1, r12, r1, lsl #8
        strb    r3, [r0, #1]
        orr     r3, r6, r2, lsl #8
        strb    lr, [r0]
        orr     r1, r1, r3, lsl #16
        strb    r1, [r0, #4]!
        strb    r2, [r0, #3]
        strb    r6, [r0, #2]
        mov     r0, #1
        pop     {r4, r5, r6, pc}
.Lfunc_end0:

gistfile2.txt

#include <string.h>
#include <stdlib.h>

int mcp(unsigned char *dst, unsigned char *src)
{
    memcpy(dst, src, 8);
    return 1;
}