ni...@lysator.liu.se (Niels Möller) writes: > So it should be doable with the addmul_1 loop and two additional, > non-recurrency, not instructions per limb, and then maybe some extra > logic for the return value. One could aim for 4.25 c/l, I guess.
The below seems to give correct results. But still 5.25 c/l. Maybe scheduling can be improved, I just put the new mvn instructions immediately preceding umaal and str. Regards, /Niels dnl ARM mpn_submul_1. dnl Copyright 2012 Free Software Foundation, Inc. dnl This file is part of the GNU MP Library. dnl The GNU MP Library is free software; you can redistribute it and/or modify dnl it under the terms of the GNU Lesser General Public License as published dnl by the Free Software Foundation; either version 3 of the License, or (at dnl your option) any later version. 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 Lesser General Public dnl License for more details. dnl You should have received a copy of the GNU Lesser General Public License dnl along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. include(`../config.m4') C cycles/limb C StrongARM: - C XScale - C Cortex-A7 ? C Cortex-A8 ? C Cortex-A9 5.25 C Cortex-A15 ? C TODO C * Micro-optimise feed-in code. C * Optimise for n=1,2 by delaying register saving. C * Try using ldm/stm. define(`rp',`r0') define(`up',`r1') define(`n', `r2') define(`v0',`r3') ASM_START() PROLOGUE(mpn_submul_1) stmfd sp!, { r4, r5, r6, r7 } ands r6, n, #3 mov r12, #0 beq L(fi0) cmp r6, #2 bcc L(fi1) beq L(fi2) L(fi3): ldr r4, [up], #4 ldr r6, [rp, #0] ldr r5, [up], #4 b L(lo3) L(fi0): ldr r5, [up], #4 ldr r7, [rp], #4 ldr r4, [up], #4 b L(lo0) L(fi1): ldr r4, [up], #4 ldr r6, [rp], #8 subs n, n, #1 beq L(1) ldr r5, [up], #4 b L(lo1) L(fi2): ldr r5, [up], #4 ldr r7, [rp], #12 ldr r4, [up], #4 b L(lo2) ALIGN(16) L(top): ldr r6, [rp, #-8] ldr r5, [up], #4 mvn r7, r7 str r7, [rp, #-12] L(lo1): mvn r6, r6 umaal r6, r12, r4, v0 ldr r7, [rp, #-4] ldr r4, [up], #4 mvn r6, r6 str r6, [rp, #-8] L(lo0): mvn r7, r7 umaal r7, r12, r5, v0 ldr r6, [rp, #0] ldr r5, [up], #4 mvn r7, r7 str r7, [rp, #-4] L(lo3): mvn r6, r6 umaal r6, r12, r4, v0 ldr r7, [rp, #4] ldr r4, [up], #4 mvn r6, r6 str r6, [rp], #16 L(lo2): mvn r7, r7 umaal r7, r12, r5, v0 subs n, n, #4 bhi L(top) ldr r6, [rp, #-8] mvn r7, r7 str r7, [rp, #-12] L(1): mvn r6, r6 umaal r6, r12, r4, v0 mvn r6, r6 str r6, [rp, #-8] mov r0, r12 ldmfd sp!, { r4, r5, r6, r7 } bx lr EPILOGUE() -- Niels Möller. PGP-encrypted email is preferred. Keyid C0B98E26. Internet email is subject to wholesale government surveillance. _______________________________________________ gmp-devel mailing list gmp-devel@gmplib.org http://gmplib.org/mailman/listinfo/gmp-devel
