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1/* Copyright (C) 1996-2019 Free Software Foundation, Inc.
2 Contributed by David Mosberger (davidm@cs.arizona.edu).
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <http://www.gnu.org/licenses/>. */
18
19/* Finds the first bit set in an integer. Optimized for the Alpha
20 architecture. */
21
22#include <sysdep.h>
23
24 .set noreorder
25 .set noat
26
27
28ENTRY(__ffs)
29#ifdef PROF
30 ldgp gp, 0(pv)
31 lda AT, _mcount
32 jsr AT, (AT), _mcount
33 .prologue 1
34 zap $16, 0xF0, $16
35 br $ffsl..ng
36#else
37 .prologue 0
38 zap $16, 0xF0, $16
39 # FALLTHRU
40#endif
41END(__ffs)
42
43 .align 4
44ENTRY(ffsl)
45#ifdef PROF
46 ldgp gp, 0(pv)
47 lda AT, _mcount
48 jsr AT, (AT), _mcount
49 .prologue 1
50$ffsl..ng:
51#else
52 .prologue 0
53#endif
54 not $16, $1 # e0 :
55 ldi $2, -1 # .. e1 :
56 cmpbge $1, $2, $3 # e0 : bit N == 1 for byte N == 0
57 clr $0 # .. e1 :
58 addq $3, 1, $4 # e0 :
59 bic $4, $3, $3 # e1 : bit N == 1 for first byte N != 0
60 and $3, 0xF0, $4 # e0 :
61 and $3, 0xCC, $5 # .. e1 :
62 and $3, 0xAA, $6 # e0 :
63 cmovne $4, 4, $0 # .. e1 :
64 cmovne $5, 2, $5 # e0 :
65 cmovne $6, 1, $6 # .. e1 :
66 addl $0, $5, $0 # e0 :
67 addl $0, $6, $0 # e1 : $0 == N
68 extbl $16, $0, $1 # e0 : $1 == byte N
69 ldi $2, 1 # .. e1 :
70 negq $1, $3 # e0 :
71 and $3, $1, $3 # e1 : bit N == least bit set of byte N
72 and $3, 0xF0, $4 # e0 :
73 and $3, 0xCC, $5 # .. e1 :
74 and $3, 0xAA, $6 # e0 :
75 cmovne $4, 5, $2 # .. e1 :
76 cmovne $5, 2, $5 # e0 :
77 cmovne $6, 1, $6 # .. e1 :
78 s8addl $0, $2, $0 # e0 : mult byte ofs by 8 and sum
79 addl $5, $6, $5 # .. e1 :
80 addl $0, $5, $0 # e0 :
81 nop # .. e1 :
82 cmoveq $16, 0, $0 # e0 : trap input == 0 case.
83 ret # .. e1 : 18
84
85END(ffsl)
86
87weak_alias (__ffs, ffs)
88libc_hidden_def (__ffs)
89libc_hidden_builtin_def (ffs)
90weak_extern (ffsl)
91weak_alias (ffsl, ffsll)
92

Warning: That file was not part of the compilation database. It may have many parsing errors.