1/* Shift a limb left, low level routine.
2   Copyright (C) 1996-2021 Free Software Foundation, Inc.
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   <https://www.gnu.org/licenses/>.  */
18
19#include <sysdep.h>
20
21/* mp_limb_t mpn_lshift (mp_ptr wp, mp_srcptr up, mp_size_t usize,
22			 unsigned int cnt)  */
23
24EALIGN (__mpn_lshift, 3, 0)
25
26	mtctr	r5		# copy size into CTR
27	cmplwi	cr0,r5,16	# is size < 16
28	slwi	r0,r5,2
29	add	r7,r3,r0	# make r7 point at end of res
30	add	r4,r4,r0	# make r4 point at end of s1
31	lwzu	r11,-4(r4)	# load first s1 limb
32	subfic	r8,r6,32
33	srw	r3,r11,r8	# compute function return value
34	bge	cr0,L(big)	# branch if size >= 16
35
36	bdz	L(end1)
37
38L(0):	lwzu	r10,-4(r4)
39	slw	r9,r11,r6
40	srw	r12,r10,r8
41	or	r9,r9,r12
42	stwu	r9,-4(r7)
43	bdz	L(end2)
44	lwzu	r11,-4(r4)
45	slw	r9,r10,r6
46	srw	r12,r11,r8
47	or	r9,r9,r12
48	stwu	r9,-4(r7)
49	bdnz	L(0)
50
51L(end1):slw	r0,r11,r6
52	stw	r0,-4(r7)
53	blr
54
55
56/* Guaranteed not to succeed.  */
57L(boom): tweq    r0,r0
58
59/* We imitate a case statement, by using (yuk!) fixed-length code chunks,
60   of size 4*12 bytes.  We have to do this (or something) to make this PIC.  */
61L(big):	mflr    r9
62	cfi_register(lr,r9)
63	bltl-   cr0,L(boom)	# Never taken, only used to set LR.
64	slwi    r10,r6,4
65	mflr    r12
66	add     r10,r12,r10
67	slwi	r8,r6,5
68	add     r10,r8,r10
69	mtctr   r10
70	addi	r5,r5,-1
71	mtlr	r9
72	cfi_same_value (lr)
73	bctr
74
75L(end2):slw	r0,r10,r6
76	stw	r0,-4(r7)
77	blr
78
79#define DO_LSHIFT(n) \
80	mtctr	r5;							\
81L(n):	lwzu	r10,-4(r4);						\
82	slwi	r9,r11,n;						\
83	inslwi	r9,r10,n,32-n;					\
84	stwu	r9,-4(r7);						\
85	bdz-	L(end2);						\
86	lwzu	r11,-4(r4);						\
87	slwi	r9,r10,n;						\
88	inslwi	r9,r11,n,32-n;					\
89	stwu	r9,-4(r7);						\
90	bdnz	L(n);							\
91	b	L(end1)
92
93	DO_LSHIFT(1)
94	DO_LSHIFT(2)
95	DO_LSHIFT(3)
96	DO_LSHIFT(4)
97	DO_LSHIFT(5)
98	DO_LSHIFT(6)
99	DO_LSHIFT(7)
100	DO_LSHIFT(8)
101	DO_LSHIFT(9)
102	DO_LSHIFT(10)
103	DO_LSHIFT(11)
104	DO_LSHIFT(12)
105	DO_LSHIFT(13)
106	DO_LSHIFT(14)
107	DO_LSHIFT(15)
108	DO_LSHIFT(16)
109	DO_LSHIFT(17)
110	DO_LSHIFT(18)
111	DO_LSHIFT(19)
112	DO_LSHIFT(20)
113	DO_LSHIFT(21)
114	DO_LSHIFT(22)
115	DO_LSHIFT(23)
116	DO_LSHIFT(24)
117	DO_LSHIFT(25)
118	DO_LSHIFT(26)
119	DO_LSHIFT(27)
120	DO_LSHIFT(28)
121	DO_LSHIFT(29)
122	DO_LSHIFT(30)
123	DO_LSHIFT(31)
124
125END (__mpn_lshift)
126