dnl  SPARC mpn_sub_n -- Subtract two limb vectors of the same length > 0 and
dnl  store difference in a third limb vector.

dnl  Copyright 2001 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
dnl  by the Free Software Foundation; either version 2.1 of the License, or (at
dnl  your 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
dnl  to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
dnl  Boston, MA 02110-1301, USA.


include(`../config.m4')

C INPUT PARAMETERS
define(rp,%o0)
define(s1p,%o1)
define(s2p,%o2)
define(n,%o3)
define(cy,%g1)

C This code uses 64-bit operations on `o' and `g' registers.  It doesn't
C require that `o' registers' upper 32 bits are preserved by the operating
C system, but if they are not, they must be zeroed.  That is indeed what
C happens at least on Slowaris 2.5 and 2.6.

C On UltraSPARC 1 and 2, this code runs at 3 cycles/limb from the Dcache and at
C about 10 cycles/limb from the Ecache.

ASM_START()
PROLOGUE(mpn_sub_n)
	lduw	[s1p+0],%o4
	lduw	[s2p+0],%o5
	addcc	n,-2,n
	bl,pn	%icc,L(end1)
	lduw	[s1p+4],%g2
	lduw	[s2p+4],%g3
	be,pn	%icc,L(end2)
	mov	0,cy

	.align	16
L(loop):
	sub	%o4,%o5,%g4
	add	rp,8,rp
	lduw	[s1p+8],%o4
	fitod	%f0,%f2
C ---
	sub	%g4,cy,%g4
	addcc	n,-1,n
	lduw	[s2p+8],%o5
	fitod	%f0,%f2
C ---
	srlx	%g4,63,cy
	add	s2p,8,s2p
	stw	%g4,[rp-8]
	be,pn	%icc,L(exito)+4
C ---
	sub	%g2,%g3,%g4
	addcc	n,-1,n
	lduw	[s1p+12],%g2
	fitod	%f0,%f2
C ---
	sub	%g4,cy,%g4
	add	s1p,8,s1p
	lduw	[s2p+4],%g3
	fitod	%f0,%f2
C ---
	srlx	%g4,63,cy
	bne,pt	%icc,L(loop)
	stw	%g4,[rp-4]
C ---
L(exite):
	sub	%o4,%o5,%g4
	sub	%g4,cy,%g4
	srlx	%g4,63,cy
	stw	%g4,[rp+0]
	sub	%g2,%g3,%g4
	sub	%g4,cy,%g4
	stw	%g4,[rp+4]
	retl
	srlx	%g4,63,%o0

L(exito):
	sub	%g2,%g3,%g4
	sub	%g4,cy,%g4
	srlx	%g4,63,cy
	stw	%g4,[rp-4]
	sub	%o4,%o5,%g4
	sub	%g4,cy,%g4
	stw	%g4,[rp+0]
	retl
	srlx	%g4,63,%o0

L(end1):
	sub	%o4,%o5,%g4
	stw	%g4,[rp+0]
	retl
	srlx	%g4,63,%o0

L(end2):
	sub	%o4,%o5,%g4
	srlx	%g4,63,cy
	stw	%g4,[rp+0]
	sub	%g2,%g3,%g4
	sub	%g4,cy,%g4
	stw	%g4,[rp+4]
	retl
	srlx	%g4,63,%o0
EPILOGUE(mpn_sub_n)