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/* Shift a limb left, low level routine.
Copyright (C) 1996-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
/* mp_limb_t mpn_lshift (mp_ptr wp, mp_srcptr up, mp_size_t usize,
unsigned int cnt) */
EALIGN (__mpn_lshift, 3, 0)
mtctr r5 # copy size into CTR
cmplwi cr0,r5,16 # is size < 16
slwi r0,r5,2
add r7,r3,r0 # make r7 point at end of res
add r4,r4,r0 # make r4 point at end of s1
lwzu r11,-4(r4) # load first s1 limb
subfic r8,r6,32
srw r3,r11,r8 # compute function return value
bge cr0,L(big) # branch if size >= 16
bdz L(end1)
L(0): lwzu r10,-4(r4)
slw r9,r11,r6
srw r12,r10,r8
or r9,r9,r12
stwu r9,-4(r7)
bdz L(end2)
lwzu r11,-4(r4)
slw r9,r10,r6
srw r12,r11,r8
or r9,r9,r12
stwu r9,-4(r7)
bdnz L(0)
L(end1):slw r0,r11,r6
stw r0,-4(r7)
blr
/* Guaranteed not to succeed. */
L(boom): tweq r0,r0
/* We imitate a case statement, by using (yuk!) fixed-length code chunks,
of size 4*12 bytes. We have to do this (or something) to make this PIC. */
L(big): mflr r9
cfi_register(lr,r9)
bltl- cr0,L(boom) # Never taken, only used to set LR.
slwi r10,r6,4
mflr r12
add r10,r12,r10
slwi r8,r6,5
add r10,r8,r10
mtctr r10
addi r5,r5,-1
mtlr r9
cfi_same_value (lr)
bctr
L(end2):slw r0,r10,r6
stw r0,-4(r7)
blr
#define DO_LSHIFT(n) \
mtctr r5; \
L(n): lwzu r10,-4(r4); \
slwi r9,r11,n; \
inslwi r9,r10,n,32-n; \
stwu r9,-4(r7); \
bdz- L(end2); \
lwzu r11,-4(r4); \
slwi r9,r10,n; \
inslwi r9,r11,n,32-n; \
stwu r9,-4(r7); \
bdnz L(n); \
b L(end1)
DO_LSHIFT(1)
DO_LSHIFT(2)
DO_LSHIFT(3)
DO_LSHIFT(4)
DO_LSHIFT(5)
DO_LSHIFT(6)
DO_LSHIFT(7)
DO_LSHIFT(8)
DO_LSHIFT(9)
DO_LSHIFT(10)
DO_LSHIFT(11)
DO_LSHIFT(12)
DO_LSHIFT(13)
DO_LSHIFT(14)
DO_LSHIFT(15)
DO_LSHIFT(16)
DO_LSHIFT(17)
DO_LSHIFT(18)
DO_LSHIFT(19)
DO_LSHIFT(20)
DO_LSHIFT(21)
DO_LSHIFT(22)
DO_LSHIFT(23)
DO_LSHIFT(24)
DO_LSHIFT(25)
DO_LSHIFT(26)
DO_LSHIFT(27)
DO_LSHIFT(28)
DO_LSHIFT(29)
DO_LSHIFT(30)
DO_LSHIFT(31)
END (__mpn_lshift)
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