glibc/sysdeps/sparc/sparc64/submul_1.S

/* SPARC v9 __mpn_submul_1 -- Multiply a limb vector with a single limb and
   subtract the product from a second limb vector.

   Copyright (C) 1996 Free Software Foundation, Inc.

   This file is part of the GNU MP Library.

   The GNU MP Library is free software; you can redistribute it and/or modify
   it under the terms of the GNU Library General Public License as published by
   the Free Software Foundation; either version 2 of the License, or (at your
   option) any later version.

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

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

#include <sysdep.h>


/* INPUT PARAMETERS
   res_ptr	o0
   s1_ptr	o1
   size		o2
   s2_limb	o3  */

ENTRY(__mpn_submul_1)
	!#PROLOGUE#	0
	save	%sp,-128,%sp
	!#PROLOGUE#	1

	sub	%g0,%i2,%o7
	sllx	%o7,3,%g5
	sub	%i1,%g5,%o3
	sub	%i0,%g5,%o4
	mov	0,%o0			! zero cy_limb

	srl	%i3,0,%o1		! extract low 32 bits of s2_limb
	srlx	%i3,32,%i3		! extract high 32 bits of s2_limb
	mov	1,%o2
	sllx	%o2,32,%o2		! o2 = 0x100000000

	!   hi   !
             !  mid-1 !
             !  mid-2 !
		 !   lo   !
.Loop:
	sllx	%o7,3,%g1
	ldx	[%o3+%g1],%g5
	srl	%g5,0,%i0		! zero hi bits
	srlx	%g5,32,%g5
	mulx	%o1,%i0,%i4		! lo product
	mulx	%i3,%i0,%i1		! mid-1 product
	mulx	%o1,%g5,%l2		! mid-2 product
	mulx	%i3,%g5,%i5		! hi product
	srlx	%i4,32,%i0		! extract high 32 bits of lo product...
	add	%i1,%i0,%i1		! ...and add it to the mid-1 product
	addcc	%i1,%l2,%i1		! add mid products
	mov	0,%l0			! we need the carry from that add...
	movcs	%xcc,%o2,%l0		! ...compute it and...
	add	%i5,%l0,%i5		! ...add to bit 32 of the hi product
	sllx	%i1,32,%i0		! align low bits of mid product
	srl	%i4,0,%g5		! zero high 32 bits of lo product
	add	%i0,%g5,%i0		! combine into low 64 bits of result
	srlx	%i1,32,%i1		! extract high bits of mid product...
	add	%i5,%i1,%i1		! ...and add them to the high result
	addcc	%i0,%o0,%i0		! add cy_limb to low 64 bits of result
	mov	0,%g5
	movcs	%xcc,1,%g5
	add	%o7,1,%o7
	ldx	[%o4+%g1],%l1
	subcc	%l1,%i0,%i0
	movcs	%xcc,1,%g5
	stx	%i0,[%o4+%g1]
	brnz	%o7,.Loop
	 add	%i1,%g5,%o0		! compute new cy_limb

	mov	%o0,%i0
	jmpl	%i7+8,%g0
	 restore

END(__mpn_submul_1)