dnl  x86 generic mpn_sqr_basecase -- square an mpn number.

dnl  Copyright 1999, 2000, 2002, 2003 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  cycles/triangleproduct

C P5

C P6

C K6

C K7

C P4

C void mpn_sqr_basecase (mp_ptr dst, mp_srcptr src, mp_size_t size);

C

C The algorithm is basically the same as mpn/generic/sqr_basecase.c, but a

C lot of function call overheads are avoided, especially when the size is

C small.

C

C The mul1 loop is not unrolled like mul_1.asm, it doesn't seem worth the

C code size to do so here.

C

C Enhancements:

C

C The addmul loop here is also not unrolled like aorsmul_1.asm and

C mul_basecase.asm are.  Perhaps it should be done.  It'd add to the

C complexity, but if it's worth doing in the other places then it should be

C worthwhile here.

C

C A fully-unrolled style like other sqr_basecase.asm versions (k6, k7, p6)

C might be worth considering.  That'd add quite a bit to the code size, but

C only as much as is used would be dragged into L1 cache.

defframe(PARAM_SIZE,12)

defframe(PARAM_SRC, 8)

defframe(PARAM_DST, 4)

	TEXT

	ALIGN(8)

PROLOGUE(mpn_sqr_basecase)

deflit(`FRAME',0)

	movl	PARAM_SIZE, %edx

	movl	PARAM_SRC, %eax

	cmpl	$2, %edx

	movl	PARAM_DST, %ecx

	je	L(two_limbs)

	ja	L(three_or_more)

C -----------------------------------------------------------------------------

C one limb only

	C eax	src

	C ebx

	C ecx	dst

	C edx

	movl	(%eax), %eax

	mull	%eax

	movl	%eax, (%ecx)

	movl	%edx, 4(%ecx)

	ret

C -----------------------------------------------------------------------------

	ALIGN(8)

L(two_limbs):

	C eax	src

	C ebx

	C ecx	dst

	C edx

	pushl	%ebx

	pushl	%ebp

	movl	%eax, %ebx

	movl	(%eax), %eax

	mull	%eax		C src[0]^2

	pushl	%esi

	pushl	%edi

	movl	%edx, %esi	C dst[1]

	movl	%eax, (%ecx)	C dst[0]

	movl	4(%ebx), %eax

	mull	%eax		C src[1]^2

	movl	%eax, %edi	C dst[2]

	movl	%edx, %ebp	C dst[3]

	movl	(%ebx), %eax

	mull	4(%ebx)		C src[0]*src[1]

	addl	%eax, %esi

	adcl	%edx, %edi

	adcl	$0, %ebp

	addl	%esi, %eax

	adcl	%edi, %edx

	movl	%eax, 4(%ecx)

	adcl	$0, %ebp

	movl	%edx, 8(%ecx)

	movl	%ebp, 12(%ecx)

	popl	%edi

	popl	%esi

	popl	%ebp

	popl	%ebx

	ret

C -----------------------------------------------------------------------------

	ALIGN(8)

L(three_or_more):

deflit(`FRAME',0)

	C eax	src

	C ebx

	C ecx	dst

	C edx	size

	pushl	%ebx	FRAME_pushl()

	pushl	%edi	FRAME_pushl()

	pushl	%esi	FRAME_pushl()

	pushl	%ebp	FRAME_pushl()

	leal	(%ecx,%edx,4), %edi	C &dst[size], end of this mul1

	leal	(%eax,%edx,4), %esi	C &src[size]

C First multiply src[0]*src[1..size-1] and store at dst[1..size].

	movl	(%eax), %ebp		C src[0], multiplier

	movl	%edx, %ecx

	negl	%ecx			C -size

	xorl	%ebx, %ebx		C clear carry limb

	incl	%ecx			C -(size-1)

L(mul1):

	C eax	scratch

	C ebx	carry

	C ecx	counter, limbs, negative

	C edx	scratch

	C esi	&src[size]

	C edi	&dst[size]

	C ebp	multiplier

	movl	(%esi,%ecx,4), %eax

	mull	%ebp

	addl	%eax, %ebx

	adcl	$0, %edx

	movl	%ebx, (%edi,%ecx,4)

	movl	%edx, %ebx

	incl	%ecx

	jnz	L(mul1)

	movl	%ebx, (%edi)

	C Add products src[n]*src[n+1..size-1] at dst[2*n-1...], for

	C n=1..size-2.

	C

	C The last products src[size-2]*src[size-1], which is the end corner

	C of the product triangle, is handled separately at the end to save

	C looping overhead.  If size is 3 then it's only this that needs to

	C be done.

	C

	C In the outer loop %esi is a constant, and %edi just advances by 1

	C limb each time.  The size of the operation decreases by 1 limb

	C each time.

	C eax

	C ebx	carry (needing carry flag added)

	C ecx

	C edx

	C esi	&src[size]

	C edi	&dst[size]

	C ebp

	movl	PARAM_SIZE, %ecx

	subl	$3, %ecx

	jz	L(corner)

	negl	%ecx

dnl  re-use parameter space

define(VAR_OUTER,`PARAM_DST')

L(outer):

	C eax

	C ebx

	C ecx

	C edx	outer loop counter, -(size-3) to -1

	C esi	&src[size]

	C edi	dst, pointing at stored carry limb of previous loop

	C ebp

	movl	%ecx, VAR_OUTER

	addl	$4, %edi		C advance dst end

	movl	-8(%esi,%ecx,4), %ebp	C next multiplier

	subl	$1, %ecx

	xorl	%ebx, %ebx		C initial carry limb

L(inner):

	C eax	scratch

	C ebx	carry (needing carry flag added)

	C ecx	counter, -n-1 to -1

	C edx	scratch

	C esi	&src[size]

	C edi	dst end of this addmul

	C ebp	multiplier

	movl	(%esi,%ecx,4), %eax

	mull	%ebp

	addl	%ebx, %eax

	adcl	$0, %edx

	addl	%eax, (%edi,%ecx,4)

	adcl	$0, %edx

	movl	%edx, %ebx

	addl	$1, %ecx

	jl	L(inner)

	movl	%ebx, (%edi)

	movl	VAR_OUTER, %ecx

	incl	%ecx

	jnz	L(outer)

L(corner):

	C esi	&src[size]

	C edi	&dst[2*size-3]

	movl	-4(%esi), %eax

	mull	-8(%esi)		C src[size-1]*src[size-2]

	addl	%eax, 0(%edi)

	adcl	$0, %edx

	movl	%edx, 4(%edi)		C dst high limb

C -----------------------------------------------------------------------------

C Left shift of dst[1..2*size-2], high bit shifted out becomes dst[2*size-1].

	movl	PARAM_SIZE, %eax

	negl	%eax

	addl	$1, %eax		C -(size-1) and clear carry

L(lshift):

	C eax	counter, negative

	C ebx	next limb

	C ecx

	C edx

	C esi

	C edi	&dst[2*size-4]

	C ebp

	rcll	8(%edi,%eax,8)

	rcll	12(%edi,%eax,8)

	incl	%eax

	jnz	L(lshift)

	adcl	%eax, %eax		C high bit out

	movl	%eax, 8(%edi)		C dst most significant limb

C Now add in the squares on the diagonal, namely src[0]^2, src[1]^2, ...,

C src[size-1]^2.  dst[0] hasn't yet been set at all yet, and just gets the

C low limb of src[0]^2.

	movl	PARAM_SRC, %esi

	movl	(%esi), %eax		C src[0]

	mull	%eax			C src[0]^2

	movl	PARAM_SIZE, %ecx

	leal	(%esi,%ecx,4), %esi	C src end

	negl	%ecx			C -size

	movl	%edx, %ebx		C initial carry

	movl	%eax, 12(%edi,%ecx,8)	C dst[0]

	incl	%ecx			C -(size-1)

L(diag):

	C eax	scratch (low product)

	C ebx	carry limb

	C ecx	counter, -(size-1) to -1

	C edx	scratch (high product)

	C esi	&src[size]

	C edi	&dst[2*size-3]

	C ebp	scratch (fetched dst limbs)

	movl	(%esi,%ecx,4), %eax

	mull	%eax

	addl	%ebx, 8(%edi,%ecx,8)

	movl	%edx, %ebx

	adcl	%eax, 12(%edi,%ecx,8)

	adcl	$0, %ebx

	incl	%ecx

	jnz	L(diag)

	addl	%ebx, 8(%edi)		C dst most significant limb

	popl	%ebp

	popl	%esi

	popl	%edi

	popl	%ebx

	ret

EPILOGUE()