dnl S/390-64 mpn_add_n and mpn_sub_n.
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
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 5.5
C z990 3
C z9 ?
C z10 6
C z196 ?
C TODO
C * Optimise for small n
C * Use r0 and save/restore one less register
C * Using logops_n's v1 inner loop operand order make the loop about 20%
C faster, at the expense of highly alignment-dependent performance.
C INPUT PARAMETERS
define(`rp', `%r2')
define(`up', `%r3')
define(`vp', `%r4')
define(`n', `%r5')
ifdef(`OPERATION_add_n', `
define(ADSB, alg)
define(ADSBCR, alcgr)
define(ADSBC, alcg)
define(RETVAL,`dnl
lghi %r2, 0
alcgr %r2, %r2')
define(func, mpn_add_n)
define(func_nc, mpn_add_nc)')
ifdef(`OPERATION_sub_n', `
define(ADSB, slg)
define(ADSBCR, slbgr)
define(ADSBC, slbg)
define(RETVAL,`dnl
slbgr %r2, %r2
lcgr %r2, %r2')
define(func, mpn_sub_n)
define(func_nc, mpn_sub_nc)')
MULFUNC_PROLOGUE(mpn_add_n mpn_sub_n)
ASM_START()
PROLOGUE(func)
stmg %r6, %r8, 48(%r15)
aghi n, 3
lghi %r7, 3
srlg %r1, n, 2
ngr %r7, n C n mod 4
je L(b1)
cghi %r7, 2
jl L(b2)
jne L(b0)
L(b3): lmg %r5, %r7, 0(up)
la up, 24(up)
ADSB %r5, 0(vp)
ADSBC %r6, 8(vp)
ADSBC %r7, 16(vp)
la vp, 24(vp)
stmg %r5, %r7, 0(rp)
la rp, 24(rp)
brctg %r1, L(top)
j L(end)
L(b0): lmg %r5, %r8, 0(up) C This redundant insns is no mistake,
la up, 32(up) C it is needed to make main loop run
ADSB %r5, 0(vp) C fast for n = 0 (mod 4).
ADSBC %r6, 8(vp)
j L(m0)
L(b1): lg %r5, 0(up)
la up, 8(up)
ADSB %r5, 0(vp)
la vp, 8(vp)
stg %r5, 0(rp)
la rp, 8(rp)
brctg %r1, L(top)
j L(end)
L(b2): lmg %r5, %r6, 0(up)
la up, 16(up)
ADSB %r5, 0(vp)
ADSBC %r6, 8(vp)
la vp, 16(vp)
stmg %r5, %r6, 0(rp)
la rp, 16(rp)
brctg %r1, L(top)
j L(end)
L(top): lmg %r5, %r8, 0(up)
la up, 32(up)
ADSBC %r5, 0(vp)
ADSBC %r6, 8(vp)
L(m0): ADSBC %r7, 16(vp)
ADSBC %r8, 24(vp)
la vp, 32(vp)
stmg %r5, %r8, 0(rp)
la rp, 32(rp)
brctg %r1, L(top)
L(end): RETVAL
lmg %r6, %r8, 48(%r15)
br %r14
EPILOGUE()