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authorDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
committerDuncan Wilkie <antigravityd@gmail.com>2023-11-18 06:11:09 -0600
commit11da511c784eca003deb90c23570f0873954e0de (patch)
treee14fdd3d5d6345956d67e79ae771d0633d28362b /gmp-6.3.0/mpn/arm64/mod_34lsub1.asm
Initial commit.
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+dnl ARM64 mpn_mod_34lsub1 -- remainder modulo 2^48-1.
+
+dnl Copyright 2012-2014 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 Cortex-A53 2
+C Cortex-A57 1
+C X-Gene 1.45
+
+define(`ap', x0)
+define(`n', x1)
+
+changecom(blah)
+
+C mp_limb_t mpn_mod_34lsub1 (mp_srcptr up, mp_size_t n)
+
+C TODO
+C * An alternative inner loop which could run at 0.722 c/l on A57:
+C adds x8, x8, x2
+C adcs x9, x9, x3
+C ldp x2, x3, [ap, #-32]
+C adcs x10, x10, x4
+C adc x12, x12, xzr
+C adds x8, x8, x5
+C ldp x4, x5, [ap, #-16]
+C sub n, n, #6
+C adcs x9, x9, x6
+C adcs x10, x10, x7
+C ldp x6, x7, [ap], #48
+C adc x12, x12, xzr
+C tbz n, #63, L(top)
+
+ASM_START()
+ TEXT
+ ALIGN(32)
+PROLOGUE(mpn_mod_34lsub1)
+ subs n, n, #3
+ mov x8, #0
+ b.lt L(le2) C n <= 2
+
+ ldp x2, x3, [ap, #0]
+ ldr x4, [ap, #16]
+ add ap, ap, #24
+ subs n, n, #3
+ b.lt L(sum) C n <= 5
+ cmn x0, #0 C clear carry
+
+L(top): ldp x5, x6, [ap, #0]
+ ldr x7, [ap, #16]
+ add ap, ap, #24
+ sub n, n, #3
+ adcs x2, x2, x5
+ adcs x3, x3, x6
+ adcs x4, x4, x7
+ tbz n, #63, L(top)
+
+ adc x8, xzr, xzr C x8 <= 1
+
+L(sum): cmn n, #2
+ mov x5, #0
+ b.lo 1f
+ ldr x5, [ap], #8
+1: mov x6, #0
+ b.ls 1f
+ ldr x6, [ap], #8
+1: adds x2, x2, x5
+ adcs x3, x3, x6
+ adcs x4, x4, xzr
+ adc x8, x8, xzr C x8 <= 2
+
+L(sum2):
+ and x0, x2, #0xffffffffffff
+ add x0, x0, x2, lsr #48
+ add x0, x0, x8
+
+ lsl x8, x3, #16
+ and x1, x8, #0xffffffffffff
+ add x0, x0, x1
+ add x0, x0, x3, lsr #32
+
+ lsl x8, x4, #32
+ and x1, x8, #0xffffffffffff
+ add x0, x0, x1
+ add x0, x0, x4, lsr #16
+ ret
+
+L(le2): cmn n, #1
+ b.ne L(1)
+ ldp x2, x3, [ap]
+ mov x4, #0
+ b L(sum2)
+L(1): ldr x2, [ap]
+ and x0, x2, #0xffffffffffff
+ add x0, x0, x2, lsr #48
+ ret
+EPILOGUE()