| Haavard Skinnemoen | 5f97f7f | 2006-09-25 23:32:13 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2004-2006 Atmel Corporation |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | */ |
| 8 | |
| 9 | /* |
| 10 | * void *memcpy(void *to, const void *from, unsigned long n) |
| 11 | * |
| 12 | * This implementation does word-aligned loads in the main loop, |
| 13 | * possibly sacrificing alignment of stores. |
| 14 | * |
| 15 | * Hopefully, in most cases, both "to" and "from" will be |
| 16 | * word-aligned to begin with. |
| 17 | */ |
| 18 | .text |
| 19 | .global memcpy |
| 20 | .type memcpy, @function |
| 21 | memcpy: |
| 22 | mov r9, r11 |
| 23 | andl r9, 3, COH |
| 24 | brne 1f |
| 25 | |
| 26 | /* At this point, "from" is word-aligned */ |
| 27 | 2: sub r10, 4 |
| 28 | mov r9, r12 |
| 29 | brlt 4f |
| 30 | |
| 31 | 3: ld.w r8, r11++ |
| 32 | sub r10, 4 |
| 33 | st.w r12++, r8 |
| 34 | brge 3b |
| 35 | |
| 36 | 4: neg r10 |
| 37 | reteq r9 |
| 38 | |
| 39 | /* Handle unaligned count */ |
| 40 | lsl r10, 2 |
| 41 | add pc, pc, r10 |
| 42 | ld.ub r8, r11++ |
| 43 | st.b r12++, r8 |
| 44 | ld.ub r8, r11++ |
| 45 | st.b r12++, r8 |
| 46 | ld.ub r8, r11++ |
| 47 | st.b r12++, r8 |
| 48 | retal r9 |
| 49 | |
| 50 | /* Handle unaligned "from" pointer */ |
| 51 | 1: sub r10, 4 |
| 52 | brlt 4b |
| 53 | add r10, r9 |
| 54 | lsl r9, 2 |
| 55 | add pc, pc, r9 |
| 56 | ld.ub r8, r11++ |
| 57 | st.b r12++, r8 |
| 58 | ld.ub r8, r11++ |
| 59 | st.b r12++, r8 |
| 60 | ld.ub r8, r11++ |
| 61 | st.b r12++, r8 |
| 62 | rjmp 2b |