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[glibc.git] / sysdeps / rs6000 / rshift.s
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1 # IBM POWER __mpn_rshift --
3 # Copyright (C) 1992, 1994 Free Software Foundation, Inc.
5 # This file is part of the GNU MP Library.
7 # The GNU MP Library is free software; you can redistribute it and/or modify
8 # it under the terms of the GNU Library General Public License as published by
9 # the Free Software Foundation; either version 2 of the License, or (at your
10 # option) any later version.
12 # The GNU MP Library is distributed in the hope that it will be useful, but
13 # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
15 # License for more details.
17 # You should have received a copy of the GNU Library General Public License
18 # along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19 # the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
20 # MA 02111-1307, USA.
23 # INPUT PARAMETERS
24 # res_ptr r3
25 # s_ptr r4
26 # size r5
27 # cnt r6
29 .toc
30 .extern __mpn_rshift[DS]
31 .extern .__mpn_rshift
32 .csect [PR]
33 .align 2
34 .globl __mpn_rshift
35 .globl .__mpn_rshift
36 .csect __mpn_rshift[DS]
37 __mpn_rshift:
38 .long .__mpn_rshift, TOC[tc0], 0
39 .csect [PR]
40 .__mpn_rshift:
41 sfi 8,6,32
42 mtctr 5 # put limb count in CTR loop register
43 l 0,0(4) # read least significant limb
44 ai 9,3,-4 # adjust res_ptr since it's offset in the stu:s
45 sle 3,0,8 # compute carry limb, and init MQ register
46 bdz Lend2 # if just one limb, skip loop
47 lu 0,4(4) # read 2:nd least significant limb
48 sleq 7,0,8 # compute least significant limb of result
49 bdz Lend # if just two limb, skip loop
50 Loop: lu 0,4(4) # load next higher limb
51 stu 7,4(9) # store previous result during read latency
52 sleq 7,0,8 # compute result limb
53 bdn Loop # loop back until CTR is zero
54 Lend: stu 7,4(9) # store 2:nd most significant limb
55 Lend2: sre 7,0,6 # compute most significant limb
56 st 7,4(9) # store it" \