diff options
author | Thomas Martitz <kugel@rockbox.org> | 2012-01-07 19:56:09 +0100 |
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committer | Thomas Martitz <kugel@rockbox.org> | 2012-01-22 18:46:45 +0100 |
commit | a035261089403de259e74ce4dd196e2715138ed2 (patch) | |
tree | 440d75109a7ebfefef2a58076b38b1bfe9db8f63 /firmware/asm/sh/memset.S | |
parent | 8e8e978de6b6283b66a6829fa8c5e3b94674ce7d (diff) | |
download | rockbox-a035261089403de259e74ce4dd196e2715138ed2.tar.gz rockbox-a035261089403de259e74ce4dd196e2715138ed2.zip |
Move optimized memcpy and friends and strlen to firmware/asm,
using the new automatic-asm-picking infrastructure.
Diffstat (limited to 'firmware/asm/sh/memset.S')
-rw-r--r-- | firmware/asm/sh/memset.S | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/firmware/asm/sh/memset.S b/firmware/asm/sh/memset.S new file mode 100644 index 0000000000..8cae1ea112 --- /dev/null +++ b/firmware/asm/sh/memset.S | |||
@@ -0,0 +1,109 @@ | |||
1 | /*************************************************************************** | ||
2 | * __________ __ ___. | ||
3 | * Open \______ \ ____ ____ | | _\_ |__ _______ ___ | ||
4 | * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / | ||
5 | * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < | ||
6 | * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ | ||
7 | * \/ \/ \/ \/ \/ | ||
8 | * $Id$ | ||
9 | * | ||
10 | * Copyright (C) 2004 by Jens Arnold | ||
11 | * | ||
12 | * This program is free software; you can redistribute it and/or | ||
13 | * modify it under the terms of the GNU General Public License | ||
14 | * as published by the Free Software Foundation; either version 2 | ||
15 | * of the License, or (at your option) any later version. | ||
16 | * | ||
17 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY | ||
18 | * KIND, either express or implied. | ||
19 | * | ||
20 | ****************************************************************************/ | ||
21 | #include "config.h" | ||
22 | |||
23 | .section .icode,"ax",@progbits | ||
24 | |||
25 | .align 2 | ||
26 | .global _memset | ||
27 | .type _memset,@function | ||
28 | |||
29 | /* Fills a memory region with specified byte value | ||
30 | * This version is optimized for speed | ||
31 | * | ||
32 | * arguments: | ||
33 | * r4 - start address | ||
34 | * r5 - data | ||
35 | * r6 - length | ||
36 | * | ||
37 | * return value: | ||
38 | * r0 - start address (like ANSI version) | ||
39 | * | ||
40 | * register usage: | ||
41 | * r0 - temporary | ||
42 | * r1 - start address +11 for main loop | ||
43 | * r4 - start address | ||
44 | * r5 - data (spread to all 4 bytes when using long stores) | ||
45 | * r6 - current address (runs down from end to start) | ||
46 | * | ||
47 | * The instruction order below is devised in a way to utilize the pipelining | ||
48 | * of the SH1 to the max. The routine fills memory from end to start in | ||
49 | * order to utilize the auto-decrementing store instructions. | ||
50 | */ | ||
51 | |||
52 | _memset: | ||
53 | neg r4,r0 | ||
54 | and #3,r0 /* r0 = (4 - align_offset) % 4 */ | ||
55 | add #4,r0 | ||
56 | cmp/hs r0,r6 /* at least one aligned longword to fill? */ | ||
57 | add r4,r6 /* r6 = end_address */ | ||
58 | bf .no_longs /* no, jump directly to byte loop */ | ||
59 | |||
60 | extu.b r5,r5 /* start: spread data to all 4 bytes */ | ||
61 | swap.b r5,r0 | ||
62 | or r0,r5 /* data now in 2 lower bytes of r5 */ | ||
63 | swap.w r5,r0 | ||
64 | or r0,r5 /* data now in all 4 bytes of r5 */ | ||
65 | |||
66 | mov r6,r0 | ||
67 | tst #3,r0 /* r0 already long aligned? */ | ||
68 | bt .end_b1 /* yes: skip loop */ | ||
69 | |||
70 | /* leading byte loop: sets 0..3 bytes */ | ||
71 | .loop_b1: | ||
72 | mov.b r5,@-r0 /* store byte */ | ||
73 | tst #3,r0 /* r0 long aligned? */ | ||
74 | bf .loop_b1 /* runs r0 down until long aligned */ | ||
75 | |||
76 | mov r0,r6 /* r6 = last long bound */ | ||
77 | nop /* keep alignment */ | ||
78 | |||
79 | .end_b1: | ||
80 | mov r4,r1 /* r1 = start_address... */ | ||
81 | add #11,r1 /* ... + 11, combined for rounding and offset */ | ||
82 | xor r1,r0 | ||
83 | tst #4,r0 /* bit 2 tells whether an even or odd number of */ | ||
84 | bf .loop_odd /* longwords to set */ | ||
85 | |||
86 | /* main loop: set 2 longs per pass */ | ||
87 | .loop_2l: | ||
88 | mov.l r5,@-r6 /* store first long */ | ||
89 | .loop_odd: | ||
90 | cmp/hi r1,r6 /* runs r6 down to first long bound */ | ||
91 | mov.l r5,@-r6 /* store second long */ | ||
92 | bt .loop_2l | ||
93 | |||
94 | .no_longs: | ||
95 | cmp/hi r4,r6 /* any bytes left? */ | ||
96 | bf .end_b2 /* no: skip loop */ | ||
97 | |||
98 | /* trailing byte loop */ | ||
99 | .loop_b2: | ||
100 | mov.b r5,@-r6 /* store byte */ | ||
101 | cmp/hi r4,r6 /* runs r6 down to the start address */ | ||
102 | bt .loop_b2 | ||
103 | |||
104 | .end_b2: | ||
105 | rts | ||
106 | mov r4,r0 /* return start address */ | ||
107 | |||
108 | .end: | ||
109 | .size _memset,.end-_memset | ||