dnl  SPARC v9 mpn_add_n -- Add two limb vectors of the same length > 0 and
dnl  store sum in a third limb vector.

dnl  Copyright 2001, 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
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		   cycles/limb
C UltraSPARC 1&2:     4
C UltraSPARC 3:	      4.5

C Compute carry-out from the most significant bits of u,v, and r, where
C r=u+v+carry_in, using logic operations.

C This code runs at 4 cycles/limb on UltraSPARC 1 and 2.  It has a 4 insn
C recurrency, and the UltraSPARC 1 and 2 the IE units are 100% saturated.
C Therefore, it seems futile to try to optimize this any further...

C INPUT PARAMETERS
define(`rp',`%i0')
define(`up',`%i1')
define(`vp',`%i2')
define(`n',`%i3')

define(`u0',`%l0')
define(`u1',`%l2')
define(`u2',`%l4')
define(`u3',`%l6')
define(`v0',`%l1')
define(`v1',`%l3')
define(`v2',`%l5')
define(`v3',`%l7')

define(`cy',`%i4')

define(`fanop',`fitod %f0,%f2')		dnl  A quasi nop running in the FA pipe
define(`fmnop',`fmuld %f0,%f0,%f4')	dnl  A quasi nop running in the FM pipe

ASM_START()
	REGISTER(%g2,#scratch)
	REGISTER(%g3,#scratch)
PROLOGUE(mpn_add_n)
	save	%sp,-160,%sp

	fitod	%f0,%f0		C make sure f0 contains small, quiet number
	subcc	n,4,%g0
	bl,pn	%icc,.Loop0
	mov	0,cy

	ldx	[up+0],u0
	ldx	[vp+0],v0
	add	up,32,up
	ldx	[up-24],u1
	ldx	[vp+8],v1
	add	vp,32,vp
	ldx	[up-16],u2
	ldx	[vp-16],v2
	ldx	[up-8],u3
	ldx	[vp-8],v3
	subcc	n,8,n
	add	u0,v0,%g1	C main add
	add	%g1,cy,%g4	C carry add
	or	u0,v0,%g2
	bl,pn	%icc,.Lend4567
	fanop
	b,a	.Loop

	.align	16
C START MAIN LOOP
.Loop:	andn	%g2,%g4,%g2
	and	u0,v0,%g3
	ldx	[up+0],u0
	fanop
C --
	or	%g3,%g2,%g2
	ldx	[vp+0],v0
	add	up,32,up
	fanop
C --
	srlx	%g2,63,cy
	add	u1,v1,%g1
	stx	%g4,[rp+0]
	fanop
C --
	add	%g1,cy,%g4
	or	u1,v1,%g2
	fmnop
	fanop
C --
	andn	%g2,%g4,%g2
	and	u1,v1,%g3
	ldx	[up-24],u1
	fanop
C --
	or	%g3,%g2,%g2
	ldx	[vp+8],v1
	add	vp,32,vp
	fanop
C --
	srlx	%g2,63,cy
	add	u2,v2,%g1
	stx	%g4,[rp+8]
	fanop
C --
	add	%g1,cy,%g4
	or	u2,v2,%g2
	fmnop
	fanop
C --
	andn	%g2,%g4,%g2
	and	u2,v2,%g3
	ldx	[up-16],u2
	fanop
C --
	or	%g3,%g2,%g2
	ldx	[vp-16],v2
	add	rp,32,rp
	fanop
C --
	srlx	%g2,63,cy
	add	u3,v3,%g1
	stx	%g4,[rp-16]
	fanop
C --
	add	%g1,cy,%g4
	or	u3,v3,%g2
	fmnop
	fanop
C --
	andn	%g2,%g4,%g2
	and	u3,v3,%g3
	ldx	[up-8],u3
	fanop
C --
	or	%g3,%g2,%g2
	subcc	n,4,n
	ldx	[vp-8],v3
	fanop
C --
	srlx	%g2,63,cy
	add	u0,v0,%g1
	stx	%g4,[rp-8]
	fanop
C --
	add	%g1,cy,%g4
	or	u0,v0,%g2
	bge,pt	%icc,.Loop
	fanop
C END MAIN LOOP
.Lend4567:
	andn	%g2,%g4,%g2
	and	u0,v0,%g3
	or	%g3,%g2,%g2
	srlx	%g2,63,cy
	add	u1,v1,%g1
	stx	%g4,[rp+0]
	add	%g1,cy,%g4
	or	u1,v1,%g2
	andn	%g2,%g4,%g2
	and	u1,v1,%g3
	or	%g3,%g2,%g2
	srlx	%g2,63,cy
	add	u2,v2,%g1
	stx	%g4,[rp+8]
	add	%g1,cy,%g4
	or	u2,v2,%g2
	andn	%g2,%g4,%g2
	and	u2,v2,%g3
	or	%g3,%g2,%g2
	add	rp,32,rp
	srlx	%g2,63,cy
	add	u3,v3,%g1
	stx	%g4,[rp-16]
	add	%g1,cy,%g4
	or	u3,v3,%g2
	andn	%g2,%g4,%g2
	and	u3,v3,%g3
	or	%g3,%g2,%g2
	srlx	%g2,63,cy
	stx	%g4,[rp-8]

	addcc	n,4,n
	bz,pn	%icc,.Lret
	fanop

.Loop0:	ldx	[up],u0
	add	up,8,up
	ldx	[vp],v0
	add	vp,8,vp
	add	rp,8,rp
	subcc	n,1,n
	add	u0,v0,%g1
	or	u0,v0,%g2
	add	%g1,cy,%g4
	and	u0,v0,%g3
	andn	%g2,%g4,%g2
	stx	%g4,[rp-8]
	or	%g3,%g2,%g2
	bnz,pt	%icc,.Loop0
	srlx	%g2,63,cy

.Lret:	mov	cy,%i0
	ret
	restore
EPILOGUE(mpn_add_n)
