github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/arm/lshift.asm (about)

     1  dnl  ARM mpn_lshift.
     2  
     3  dnl  Contributed to the GNU project by Torbjörn Granlund.
     4  
     5  dnl  Copyright 2012 Free Software Foundation, Inc.
     6  
     7  dnl  This file is part of the GNU MP Library.
     8  dnl
     9  dnl  The GNU MP Library is free software; you can redistribute it and/or modify
    10  dnl  it under the terms of either:
    11  dnl
    12  dnl    * the GNU Lesser General Public License as published by the Free
    13  dnl      Software Foundation; either version 3 of the License, or (at your
    14  dnl      option) any later version.
    15  dnl
    16  dnl  or
    17  dnl
    18  dnl    * the GNU General Public License as published by the Free Software
    19  dnl      Foundation; either version 2 of the License, or (at your option) any
    20  dnl      later version.
    21  dnl
    22  dnl  or both in parallel, as here.
    23  dnl
    24  dnl  The GNU MP Library is distributed in the hope that it will be useful, but
    25  dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    26  dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    27  dnl  for more details.
    28  dnl
    29  dnl  You should have received copies of the GNU General Public License and the
    30  dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
    31  dnl  see https://www.gnu.org/licenses/.
    32  
    33  include(`../config.m4')
    34  
    35  C	     cycles/limb
    36  C StrongARM	 ?
    37  C XScale	 ?
    38  C Cortex-A7	 ?
    39  C Cortex-A8	 ?
    40  C Cortex-A9	 3.5
    41  C Cortex-A15	 ?
    42  
    43  define(`rp',  `r0')
    44  define(`up',  `r1')
    45  define(`n',   `r2')
    46  define(`cnt', `r3')
    47  define(`tnc', `r12')
    48  
    49  ASM_START()
    50  PROLOGUE(mpn_lshift)
    51  	add	up, up, n, lsl #2
    52  	push	{r4, r6, r7, r8}
    53  	ldr	r4, [up, #-4]!
    54  	add	rp, rp, n, lsl #2
    55  	rsb	tnc, cnt, #32
    56  
    57  	mov	r7, r4, lsl cnt
    58  	tst	n, #1
    59  	beq	L(evn)			C n even
    60  
    61  L(odd):	subs	n, n, #2
    62  	bcc	L(1)			C n = 1
    63  	ldr	r8, [up, #-4]!
    64  	b	L(mid)
    65  
    66  L(evn):	ldr	r6, [up, #-4]!
    67  	subs	n, n, #2
    68  	beq	L(end)
    69  
    70  L(top):	ldr	r8, [up, #-4]!
    71  	orr	r7, r7, r6, lsr tnc
    72  	str	r7, [rp, #-4]!
    73  	mov	r7, r6, lsl cnt
    74  L(mid):	ldr	r6, [up, #-4]!
    75  	orr	r7, r7, r8, lsr tnc
    76  	str	r7, [rp, #-4]!
    77  	mov	r7, r8, lsl cnt
    78  	subs	n, n, #2
    79  	bgt	L(top)
    80  
    81  L(end):	orr	r7, r7, r6, lsr tnc
    82  	str	r7, [rp, #-4]!
    83  	mov	r7, r6, lsl cnt
    84  L(1):	str	r7, [rp, #-4]
    85  	mov	r0, r4, lsr tnc
    86  	pop	{r4, r6, r7, r8}
    87  	ret	r14
    88  EPILOGUE()