dnl  x86 mpn_mul_basecase -- Multiply two limb vectors and store the result

dnl  in a third limb vector.

dnl  Copyright 1996-2002 Free Software Foundation, Inc.

dnl  This file is part of the GNU MP Library.

dnl

dnl  The GNU MP Library is free software; you can redistribute it and/or modify

dnl  it under the terms of either:

dnl

dnl    * the GNU Lesser General Public License as published by the Free

dnl      Software Foundation; either version 3 of the License, or (at your

dnl      option) any later version.

dnl

dnl  or

dnl

dnl    * the GNU General Public License as published by the Free Software

dnl      Foundation; either version 2 of the License, or (at your option) any

dnl      later version.

dnl

dnl  or both in parallel, as here.

dnl

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 General Public License

dnl  for more details.

dnl

dnl  You should have received copies of the GNU General Public License and the

dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,

dnl  see https://www.gnu.org/licenses/.

include(`../config.m4')

C     cycles/crossproduct

C P5	  15

C P6	   7.5

C K6	  12.5

C K7	   5.5

C P4	  24

C void mpn_mul_basecase (mp_ptr wp,

C                        mp_srcptr xp, mp_size_t xsize,

C                        mp_srcptr yp, mp_size_t ysize);

C

C This was written in a haste since the Pentium optimized code that was used

C for all x86 machines was slow for the Pentium II.  This code would benefit

C from some cleanup.

C

C To shave off some percentage of the run-time, one should make 4 variants

C of the Louter loop, for the four different outcomes of un mod 4.  That

C would avoid Loop0 altogether.  Code expansion would be > 4-fold for that

C part of the function, but since it is not very large, that would be

C acceptable.

C

C The mul loop (at L(oopM)) might need some tweaking.  It's current speed is

C unknown.

defframe(PARAM_YSIZE,20)

defframe(PARAM_YP,   16)

defframe(PARAM_XSIZE,12)

defframe(PARAM_XP,   8)

defframe(PARAM_WP,   4)

defframe(VAR_MULTIPLIER, -4)

defframe(VAR_COUNTER,    -8)

deflit(VAR_STACK_SPACE,  8)

	TEXT

	ALIGN(8)

PROLOGUE(mpn_mul_basecase)

deflit(`FRAME',0)

	subl	$VAR_STACK_SPACE,%esp

	pushl	%esi

	pushl	%ebp

	pushl	%edi

deflit(`FRAME',eval(VAR_STACK_SPACE+12))

	movl	PARAM_XP,%esi

	movl	PARAM_WP,%edi

	movl	PARAM_YP,%ebp

	movl	(%esi),%eax		C load xp[0]

	mull	(%ebp)			C multiply by yp[0]

	movl	%eax,(%edi)		C store to wp[0]

	movl	PARAM_XSIZE,%ecx	C xsize

	decl	%ecx			C If xsize = 1, ysize = 1 too

	jz	L(done)

	pushl	%ebx

FRAME_pushl()

	movl	%edx,%ebx

	leal	4(%esi),%esi

	leal	4(%edi),%edi

L(oopM):

	movl	(%esi),%eax		C load next limb at xp[j]

	leal	4(%esi),%esi

	mull	(%ebp)

	addl	%ebx,%eax

	movl	%edx,%ebx

	adcl	$0,%ebx

	movl	%eax,(%edi)

	leal	4(%edi),%edi

	decl	%ecx

	jnz	L(oopM)

	movl	%ebx,(%edi)		C most significant limb of product

	addl	$4,%edi			C increment wp

	movl	PARAM_XSIZE,%eax

	shll	$2,%eax

	subl	%eax,%edi

	subl	%eax,%esi

	movl	PARAM_YSIZE,%eax	C ysize

	decl	%eax

	jz	L(skip)

	movl	%eax,VAR_COUNTER	C set index i to ysize

L(outer):

	movl	PARAM_YP,%ebp		C yp

	addl	$4,%ebp			C make ebp point to next v limb

	movl	%ebp,PARAM_YP

	movl	(%ebp),%eax		C copy y limb ...

	movl	%eax,VAR_MULTIPLIER	C ... to stack slot

	movl	PARAM_XSIZE,%ecx

	xorl	%ebx,%ebx

	andl	$3,%ecx

	jz	L(end0)

L(oop0):

	movl	(%esi),%eax

	mull	VAR_MULTIPLIER

	leal	4(%esi),%esi

	addl	%ebx,%eax

	movl	$0,%ebx

	adcl	%ebx,%edx

	addl	%eax,(%edi)

	adcl	%edx,%ebx		C propagate carry into cylimb

	leal	4(%edi),%edi

	decl	%ecx

	jnz	L(oop0)

L(end0):

	movl	PARAM_XSIZE,%ecx

	shrl	$2,%ecx

	jz	L(endX)

	ALIGN(8)

L(oopX):

	movl	(%esi),%eax

	mull	VAR_MULTIPLIER

	addl	%eax,%ebx

	movl	$0,%ebp

	adcl	%edx,%ebp

	movl	4(%esi),%eax

	mull	VAR_MULTIPLIER

	addl	%ebx,(%edi)

	adcl	%eax,%ebp	C new lo + cylimb

	movl	$0,%ebx

	adcl	%edx,%ebx

	movl	8(%esi),%eax

	mull	VAR_MULTIPLIER

	addl	%ebp,4(%edi)

	adcl	%eax,%ebx	C new lo + cylimb

	movl	$0,%ebp

	adcl	%edx,%ebp

	movl	12(%esi),%eax

	mull	VAR_MULTIPLIER

	addl	%ebx,8(%edi)

	adcl	%eax,%ebp	C new lo + cylimb

	movl	$0,%ebx

	adcl	%edx,%ebx

	addl	%ebp,12(%edi)

	adcl	$0,%ebx		C propagate carry into cylimb

	leal	16(%esi),%esi

	leal	16(%edi),%edi

	decl	%ecx

	jnz	L(oopX)

L(endX):

	movl	%ebx,(%edi)

	addl	$4,%edi

	C we incremented wp and xp in the loop above; compensate

	movl	PARAM_XSIZE,%eax

	shll	$2,%eax

	subl	%eax,%edi

	subl	%eax,%esi

	movl	VAR_COUNTER,%eax

	decl	%eax

	movl	%eax,VAR_COUNTER

	jnz	L(outer)

L(skip):

	popl	%ebx

	popl	%edi

	popl	%ebp

	popl	%esi

	addl	$8,%esp

	ret

L(done):

	movl	%edx,4(%edi)	   C store to wp[1]

	popl	%edi

	popl	%ebp

	popl	%esi

	addl	$8,%esp

	ret

EPILOGUE()