1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
|
/* ------------------------------------------------------------------ */
/* | Copyright Unpublished, MIPS Computer Systems, Inc. All Rights | */
/* | Reserved. This software contains proprietary and confidential | */
/* | information of MIPS and its suppliers. Use, disclosure or | */
/* | reproduction is prohibited without the prior express written | */
/* | consent of MIPS. | */
/* ------------------------------------------------------------------ */
/* strcmp.s 1.1 */
/* This function is an assembly-code replacement for
the libc function "strcmp." */
/* Libc currently has a mips-specific C version that uses 7 instructions/byte.
(It claims to use 6 cycles/byte, but is wrong!)
This function uses an unrolled loop, which uses 5 instructions per byte.
Under some circumstances more characters are read than are
required for determining the collating order, but it
never reads beyond the end of either string.
There are one caveat to consider: this function is written
in assembler code, and as such, cannot be merged
using the U-code loader. */
/* Craig Hansen - 6-June-86 */
#include <kxmips.h>
.text
LEAF_ENTRY(strcmp)
.set noreorder
lbu t0,0(a0)
1: lbu t1,0(a1)
beq t0,0,2f
addi a0,2
bne t0,t1,3f
lbu t2,-1(a0) # ok to load since -2(a0)!=0
lbu t1,1(a1)
beq t2,0,2f
addi a1,2
beq t2,t1,1b
lbu t0,0(a0) # ok to load since -1(a0) != 0
j ra
subu v0,t2,t1
2: j ra
subu v0,zero,t1
3: j ra
subu v0,t0,t1
.end strcmp
|
