| .text | |
| .syntax unified | |
| .global memcpy | |
| .func memcpy | |
| .thumb_func | |
| memcpy: | |
| /* on entry | |
| * r0 = targ | |
| * r1 = src | |
| * r2 = len (bytes) | |
| * on exit | |
| * r0 = targ (unchanged) | |
| */ | |
| push {r0, r4, lr} | |
| /* If targ or src are unaligned, drop to byte | |
| * processing. */ | |
| mov r3, r0 | |
| movs r4, #3 | |
| orrs r3, r1 | |
| ands r3, r4 | |
| bne L_bytewise | |
| /* Process words */ | |
| L_wordwise: | |
| cmp r2, #4 | |
| blo L_bytewise | |
| ldr r4, [r1] | |
| adds r1, #4 | |
| str r4, [r0] | |
| adds r0, #4 | |
| subs r2, #4 | |
| b L_wordwise | |
| /* Process bytes */ | |
| L_bytewise: | |
| cmp r2, #0 | |
| beq L_fin | |
| ldrb r4, [r1] | |
| adds r1, #1 | |
| strb r4, [r0] | |
| adds r0, #1 | |
| subs r2, #1 | |
| b L_bytewise | |
| L_fin: | |
| pop {r0, r4, pc} | |
| .endfunc |