| /* |
| Copyright 2003 Richard Curnow, SuperH (UK) Ltd. |
| |
| This file is subject to the terms and conditions of the GNU General Public |
| License. See the file "COPYING" in the main directory of this archive |
| for more details. |
| |
| Tight version of memset for the case of just clearing a page. It turns out |
| that having the alloco's spaced out slightly due to the increment/branch |
| pair causes them to contend less for access to the cache. Similarly, |
| keeping the stores apart from the allocos causes less contention. => Do two |
| separate loops. Do multiple stores per loop to amortise the |
| increment/branch cost a little. |
| |
| Parameters: |
| r2 : source effective address (start of page) |
| |
| Always clears 4096 bytes. |
| |
| Note : alloco guarded by synco to avoid TAKum03020 erratum |
| |
| */ |
| |
| .section .text..SHmedia32,"ax" |
| .little |
| |
| .balign 8 |
| .global clear_page |
| clear_page: |
| pta/l 1f, tr1 |
| pta/l 2f, tr2 |
| ptabs/l r18, tr0 |
| |
| movi 4096, r7 |
| add r2, r7, r7 |
| add r2, r63, r6 |
| 1: |
| alloco r6, 0 |
| synco ! TAKum03020 |
| addi r6, 32, r6 |
| bgt/l r7, r6, tr1 |
| |
| add r2, r63, r6 |
| 2: |
| st.q r6, 0, r63 |
| st.q r6, 8, r63 |
| st.q r6, 16, r63 |
| st.q r6, 24, r63 |
| addi r6, 32, r6 |
| bgt/l r7, r6, tr2 |
| |
| blink tr0, r63 |
| |
| |
