Rewritten.
[glibc.git] / sysdeps / rs6000 / lshift.s
blob69c75020615de3295a79a6f28f17540251be0df9
1 # IBM POWER __mpn_lshift --
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., 675 Mass Ave, Cambridge, MA 02139, USA.
22 # INPUT PARAMETERS
23 # res_ptr r3
24 # s_ptr r4
25 # size r5
26 # cnt r6
28 .toc
29 .extern __mpn_lshift[DS]
30 .extern .__mpn_lshift
31 .csect [PR]
32 .align 2
33 .globl __mpn_lshift
34 .globl .__mpn_lshift
35 .csect __mpn_lshift[DS]
36 __mpn_lshift:
37 .long .__mpn_lshift, TOC[tc0], 0
38 .csect [PR]
39 .__mpn_lshift:
40 sli 0,5,2
41 cax 9,3,0
42 cax 4,4,0
43 sfi 8,6,32
44 mtctr 5 # put limb count in CTR loop register
45 lu 0,-4(4) # read most significant limb
46 sre 3,0,8 # compute carry out limb, and init MQ register
47 bdz Lend2 # if just one limb, skip loop
48 lu 0,-4(4) # read 2:nd most significant limb
49 sreq 7,0,8 # compute most significant limb of result
50 bdz Lend # if just two limb, skip loop
51 Loop: lu 0,-4(4) # load next lower limb
52 stu 7,-4(9) # store previous result during read latency
53 sreq 7,0,8 # compute result limb
54 bdn Loop # loop back until CTR is zero
55 Lend: stu 7,-4(9) # store 2:nd least significant limb
56 Lend2: sle 7,0,6 # compute least significant limb
57 st 7,-4(9) # store it" \