rshift.asm

来自「a very popular packet of cryptography to」· 汇编 代码 · 共 102 行

dnl  HP-PA 2.0 mpn_rshift -- Right shift.

dnl  Copyright 1997, 2000, 2002, 2003 Free Software Foundation, Inc.

dnl  This file is part of the GNU MP Library.

dnl  The GNU MP Library is free software; you can redistribute it and/or modify
dnl  it under the terms of the GNU Lesser General Public License as published by
dnl  the Free Software Foundation; either version 2.1 of the License, or (at your
dnl  option) any later version.

dnl  The GNU MP Library is distributed in the hope that it will be useful, but
dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
dnl  License for more details.

dnl  You should have received a copy of the GNU Lesser General Public License
dnl  along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
dnl  the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
dnl  MA 02111-1307, USA.


dnl  This runs at 1.5 cycles/limb on PA8000 and 1.0 cycles/limb on PA8500.

include(`../config.m4')

dnl  INPUT PARAMETERS
define(`rp',`%r26')
define(`up',`%r25')
define(`n',`%r24')
define(`cnt',`%r23')

ifdef(`HAVE_ABI_2_0w',
`       .level  2.0w
',`     .level  2.0
')
PROLOGUE(mpn_rshift)
	mtsar		cnt
	ldd		0(up), %r21
	addib,=		-1, n, L(end)
	shrpd		%r21, %r0, %sar, %r29	C compute carry out limb
	depw,z		n, 31, 3, %r28		C r28 = (size & 7)
	sub		%r0, n, %r22
	depw,z		%r22, 28, 3, %r22	C r22 = 8 * (-size & 7)
	sub		up, %r22, up		C offset up
	blr		%r28, %r0		C branch into jump table
	sub		rp, %r22, rp		C offset rp
	b		L(0)
	nop
	b		L(1)
	copy		%r21, %r20
	b		L(2)
	nop
	b		L(3)
	copy		%r21, %r20
	b		L(4)
	nop
	b		L(5)
	copy		%r21, %r20
	b		L(6)
	nop
	b		L(7)
	copy		%r21, %r20

L(loop)
L(0)	ldd		8(up), %r20
	shrpd		%r20, %r21, %sar, %r21
	std		%r21, 0(rp)
L(7)	ldd		16(up), %r21
	shrpd		%r21, %r20, %sar, %r20
	std		%r20, 8(rp)
L(6)	ldd		24(up), %r20
	shrpd		%r20, %r21, %sar, %r21
	std		%r21, 16(rp)
L(5)	ldd		32(up), %r21
	shrpd		%r21, %r20, %sar, %r20
	std		%r20, 24(rp)
L(4)	ldd		40(up), %r20
	shrpd		%r20, %r21, %sar, %r21
	std		%r21, 32(rp)
L(3)	ldd		48(up), %r21
	shrpd		%r21, %r20, %sar, %r20
	std		%r20, 40(rp)
L(2)	ldd		56(up), %r20
	shrpd		%r20, %r21, %sar, %r21
	std		%r21, 48(rp)
L(1)	ldd		64(up), %r21
	ldo		64(up), up
	shrpd		%r21, %r20, %sar, %r20
	std		%r20, 56(rp)
	addib,>		-8, n, L(loop)
	ldo		64(rp), rp

L(end)	shrpd		%r0, %r21, %sar, %r21
	std		%r21, 0(rp)
	bve		(%r2)
ifdef(`HAVE_ABI_2_0w',
`	copy		%r29,%r28
',`	extrd,u		%r29, 31, 32, %r28
')
EPILOGUE(mpn_rshift)