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:
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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
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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.
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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/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()