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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * arch/alpha/lib/strcat.S
3 * Contributed by Richard Henderson (rth@tamu.edu)
4 *
5 * Append a null-terminated string from SRC to DST.
6 */
7
8 .text
9
10 .align 3
11 .globl strcat
12 .ent strcat
13strcat:
14 .frame $30, 0, $26
15 .prologue 0
16
17 mov $16, $0 # set up return value
18
19 /* Find the end of the string. */
20
21 ldq_u $1, 0($16) # load first quadword (a0 may be misaligned)
22 lda $2, -1
23 insqh $2, $16, $2
24 andnot $16, 7, $16
25 or $2, $1, $1
26 cmpbge $31, $1, $2 # bits set iff byte == 0
27 bne $2, $found
28
29$loop: ldq $1, 8($16)
30 addq $16, 8, $16
31 cmpbge $31, $1, $2
32 beq $2, $loop
33
34$found: negq $2, $3 # clear all but least set bit
35 and $2, $3, $2
36
37 and $2, 0xf0, $3 # binary search for that set bit
38 and $2, 0xcc, $4
39 and $2, 0xaa, $5
40 cmovne $3, 4, $3
41 cmovne $4, 2, $4
42 cmovne $5, 1, $5
43 addq $3, $4, $3
44 addq $16, $5, $16
45 addq $16, $3, $16
46
47 /* Now do the append. */
48
49 mov $26, $23
50 br __stxcpy
51
52 .end strcat