dnl  S/390-64 mpn_sqr_basecase.

dnl  Copyright 2011 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

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

include(`../config.m4')

C            cycles/limb

C z900		 ?

C z990		23

C z9		 ?

C z10		28

C z196		 ?

C TODO

C  * Clean up.

C  * Stop iterating addmul_1 loop at latest for n = 2, implement longer tail.

C    This will ask for basecase handling of n = 3.

C  * Update counters and pointers more straightforwardly, possibly lowering

C    register usage.

C  * Should we use this allocation-free style for more sqr_basecase asm

C    implementations?  The only disadvantage is that it requires R != U.

C  * Replace loops by faster code.  The mul_1 and addmul_1 loops could be sped

C    up by about 10%.  The sqr_diag_addlsh1 loop could probably be sped up even

C    more.

C INPUT PARAMETERS

define(`rp',	`%r2')

define(`up',	`%r3')

define(`n',	`%r4')

define(`zero',	`%r8')

define(`rp_saved',	`%r9')

define(`up_saved',	`%r13')

define(`n_saved',	`%r14')

ASM_START()

PROLOGUE(mpn_sqr_basecase)

	aghi	n, -2

	jhe	L(ge2)

C n = 1

	lg	%r5, 0(up)

	mlgr	%r4, %r5

	stg	%r5, 0(rp)

	stg	%r4, 8(rp)

	br	%r14

L(ge2):	jne	L(gen)

C n = 2

	stmg	%r6, %r8, 48(%r15)

	lghi	zero, 0

	lg	%r5, 0(up)

	mlgr	%r4, %r5		C u0 * u0

	lg	%r1, 8(up)

	mlgr	%r0, %r1		C u1 * u1

	stg	%r5, 0(rp)

	lg	%r7, 0(up)

	mlg	%r6, 8(up)		C u0 * u1

	algr	%r7, %r7

	alcgr	%r6, %r6

	alcgr	%r0, zero

	algr	%r4, %r7

	alcgr	%r1, %r6

	alcgr	%r0, zero

	stg	%r4, 8(rp)

	stg	%r1, 16(rp)

	stg	%r0, 24(rp)

	lmg	%r6, %r8, 48(%r15)

	br	%r14

L(gen):

C mul_1 =======================================================================

	stmg	%r6, %r14, 48(%r15)

	lghi	zero, 0

	lgr	up_saved, up

	lgr	rp_saved, rp

	lgr	n_saved, n

	lg	%r6, 0(up)

	lg	%r11, 8(up)

	lghi	%r12, 16		C init index register

	mlgr	%r10, %r6

	lgr	%r5, n

	stg	%r11, 8(rp)

	cr	%r15, %r15		C clear carry flag

L(tm):	lg	%r1, 0(%r12,up)

	mlgr	%r0, %r6

	alcgr	%r1, %r10

	lgr	%r10, %r0		C copy high part to carry limb

	stg	%r1, 0(%r12,rp)

	la	%r12, 8(%r12)

	brctg	%r5, L(tm)

	alcgr	%r0, zero

	stg	%r0, 0(%r12,rp)

C addmul_1 loop ===============================================================

	aghi	n, -1

	je	L(outer_end)

L(outer_loop):

	la	rp, 16(rp)		C rp += 2

	la	up, 8(up)		C up += 1

	lg	%r6, 0(up)

	lg	%r11, 8(up)

	lghi	%r12, 16		C init index register

	mlgr	%r10, %r6

	lgr	%r5, n

	alg	%r11, 8(rp)

	stg	%r11, 8(rp)

L(tam):	lg	%r1, 0(%r12,up)

	lg	%r7, 0(%r12,rp)

	mlgr	%r0, %r6

	alcgr	%r1, %r7

	alcgr	%r0, zero

	algr	%r1, %r10

	lgr	%r10, %r0

	stg	%r1, 0(%r12,rp)

	la	%r12, 8(%r12)

	brctg	%r5, L(tam)

	alcgr	%r0, zero

	stg	%r0, 0(%r12,rp)

	brctg	n, L(outer_loop)

L(outer_end):

	lg	%r6, 8(up)

	lg	%r1, 16(up)

	lgr	%r7, %r0		C Same as: lg %r7, 24(,rp)

	mlgr	%r0, %r6

	algr	%r1, %r7

	alcgr	%r0, zero

	stg	%r1, 24(rp)

	stg	%r0, 32(rp)

C sqr_diag_addlsh1 ============================================================

define(`up', `up_saved')

define(`rp', `rp_saved')

	la	n, 1(n_saved)

	lg	%r1, 0(up)

	mlgr	%r0, %r1

	stg	%r1, 0(rp)

C	clr	%r15, %r15		C clear carry (already clear per above)

L(top):	lg	%r11, 8(up)

	la	up, 8(up)

	lg	%r6, 8(rp)

	lg	%r7, 16(rp)

	mlgr	%r10, %r11

	alcgr	%r6, %r6

	alcgr	%r7, %r7

	alcgr	%r10, zero		C propagate carry to high product limb

	algr	%r6, %r0

	alcgr	%r7, %r11

	stmg	%r6, %r7, 8(rp)

	la	rp, 16(rp)

	lgr	%r0, %r10		C copy carry limb

	brctg	n, L(top)

	alcgr	%r0, zero

	stg	%r0, 8(rp)

	lmg	%r6, %r14, 48(%r15)

	br	%r14

EPILOGUE()