dnl ARM Neon mpn_lshiftc. dnl Contributed to the GNU project by Torbjörn Granlund. dnl Copyright 2013 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 cycles/limb cycles/limb good C aligned unaligned best seen for cpu? C StrongARM - - C XScale - - C Cortex-A7 ? ? C Cortex-A8 ? ? C Cortex-A9 3.5 3.5 Y C Cortex-A15 1.75 1.75 Y C We read 64 bits at a time at 32-bit aligned addresses, and except for the C first and last store, we write using 64-bit aligned addresses. All shifting C is done on 64-bit words in 'extension' registers. C C It should be possible to read also using 64-bit alignment, by manipulating C the shift count for unaligned operands. Not done, since it does not seem to C matter for A9 or A15. C C This will not work in big-endian mode. C TODO C * Try using 128-bit operations. Note that Neon lacks pure 128-bit shifts, C which might make it tricky. C * Clean up and simplify. C * Consider sharing most of the code for lshift and rshift, since the feed-in C code, the loop, and most of the wind-down code are identical. C * Replace the basecase code with code using 'extension' registers. C * Optimise. It is not clear that this loop insn permutation is optimal for C either A9 or A15. C INPUT PARAMETERS define(`rp', `r0') define(`ap', `r1') define(`n', `r2') define(`cnt', `r3') define(`IFLSH', `$1') define(`IFRSH', `') define(`X',`0') define(`Y',`1') define(`func',`mpn_lshiftc') define(`OPERATION_lshiftc',1) ASM_START() TEXT ALIGN(64) PROLOGUE(mpn_lshiftc) IFLSH(` mov r12, n, lsl #2 ') IFLSH(` add rp, rp, r12 ') IFLSH(` add ap, ap, r12 ') cmp n, #4 C SIMD code n limit ble L(base) ifdef(`OPERATION_lshiftc',` vdup.32 d6, r3 C left shift count is positive sub r3, r3, #64 C right shift count is negative vdup.32 d7, r3 mov r12, #-8') C lshift pointer update offset ifdef(`OPERATION_rshift',` rsb r3, r3, #0 C right shift count is negative vdup.32 d6, r3 add r3, r3, #64 C left shift count is positive vdup.32 d7, r3 mov r12, #8') C rshift pointer update offset IFLSH(` sub ap, ap, #8 ') vld1.32 {d19}, [ap], r12 C load initial 2 limbs vshl.u64 d18, d19, d7 C retval tst rp, #4 C is rp 64-bit aligned already? beq L(rp_aligned) C yes, skip vmvn d19, d19 IFLSH(` add ap, ap, #4 ') C move back ap pointer IFRSH(` sub ap, ap, #4 ') C move back ap pointer vshl.u64 d4, d19, d6 sub n, n, #1 C first limb handled IFLSH(` sub rp, rp, #4 ') vst1.32 {d4[Y]}, [rp]IFRSH(!) C store first limb, rp gets aligned vld1.32 {d19}, [ap], r12 C load ap[1] and ap[2] L(rp_aligned): IFLSH(` sub rp, rp, #8 ') subs n, n, #6 vmvn d19, d19 blt L(two_or_three_more) tst n, #2 beq L(2) L(1): vld1.32 {d17}, [ap], r12 vshl.u64 d5, d19, d6 vmvn d17, d17 vld1.32 {d16}, [ap], r12 vshl.u64 d0, d17, d7 vshl.u64 d4, d17, d6 sub n, n, #2 b L(mid) L(2): vld1.32 {d16}, [ap], r12 vshl.u64 d4, d19, d6 vmvn d16, d16 vld1.32 {d17}, [ap], r12 vshl.u64 d1, d16, d7 vshl.u64 d5, d16, d6 subs n, n, #4 blt L(end) L(top): vmvn d17, d17 vld1.32 {d16}, [ap], r12 vorr d2, d4, d1 vshl.u64 d0, d17, d7 vshl.u64 d4, d17, d6 vst1.32 {d2}, [rp:64], r12 L(mid): vmvn d16, d16 vld1.32 {d17}, [ap], r12 vorr d3, d5, d0 vshl.u64 d1, d16, d7 vshl.u64 d5, d16, d6 vst1.32 {d3}, [rp:64], r12 subs n, n, #4 bge L(top) L(end): tst n, #1 beq L(evn) vorr d2, d4, d1 vst1.32 {d2}, [rp:64], r12 b L(cj1) L(evn): vmvn d17, d17 vorr d2, d4, d1 vshl.u64 d0, d17, d7 vshl.u64 d4, d17, d6 vst1.32 {d2}, [rp:64], r12 vmov.u8 d17, #255 vorr d2, d5, d0 vshl.u64 d0, d17, d7 vorr d3, d4, d0 b L(cj2) C Load last 2 - 3 limbs, store last 4 - 5 limbs L(two_or_three_more): tst n, #1 beq L(l2) L(l3): vshl.u64 d5, d19, d6 vld1.32 {d17}, [ap], r12 L(cj1): vmov.u8 d16, #0 IFLSH(` add ap, ap, #4 ') vmvn d17, d17 vld1.32 {d16[Y]}, [ap], r12 vshl.u64 d0, d17, d7 vshl.u64 d4, d17, d6 vmvn d16, d16 vorr d3, d5, d0 vshl.u64 d1, d16, d7 vshl.u64 d5, d16, d6 vst1.32 {d3}, [rp:64], r12 vorr d2, d4, d1 vst1.32 {d2}, [rp:64], r12 IFLSH(` add rp, rp, #4 ') vst1.32 {d5[Y]}, [rp] vmov.32 r0, d18[X] bx lr L(l2): vld1.32 {d16}, [ap], r12 vshl.u64 d4, d19, d6 vmvn d16, d16 vshl.u64 d1, d16, d7 vshl.u64 d5, d16, d6 vmov.u8 d17, #255 vorr d2, d4, d1 vshl.u64 d0, d17, d7 vorr d3, d5, d0 L(cj2): vst1.32 {d2}, [rp:64], r12 vst1.32 {d3}, [rp] vmov.32 r0, d18[X] bx lr define(`tnc', `r12') L(base): push {r4, r6, r7, r8} ldr r4, [ap, #-4]! rsb tnc, cnt, #32 mvn r6, r4 mov r7, r6, lsl cnt tst n, #1 beq L(ev) C n even L(od): subs n, n, #2 bcc L(ed1) C n = 1 ldr r8, [ap, #-4]! mvn r8, r8 b L(md) C n = 3 L(ev): ldr r6, [ap, #-4]! mvn r6, r6 subs n, n, #2 beq L(ed) C n = 3 C n = 4 L(tp): ldr r8, [ap, #-4]! orr r7, r7, r6, lsr tnc str r7, [rp, #-4]! mvn r8, r8 mov r7, r6, lsl cnt L(md): ldr r6, [ap, #-4]! orr r7, r7, r8, lsr tnc str r7, [rp, #-4]! mvn r6, r6 mov r7, r8, lsl cnt L(ed): orr r7, r7, r6, lsr tnc str r7, [rp, #-4]! mov r7, r6, lsl cnt L(ed1): mvn r6, #0 orr r7, r7, r6, lsr tnc str r7, [rp, #-4] mov r0, r4, lsr tnc pop {r4, r6, r7, r8} bx r14 EPILOGUE()