| /* Optimized version of the standard strncpy() function. |
| This file is part of the GNU C Library. |
| Copyright (C) 2000-2018 Free Software Foundation, Inc. |
| Contributed by Dan Pop <Dan.Pop@cern.ch> |
| and Jakub Jelinek <jakub@redhat.com>. |
| |
| The GNU C Library is free software; you can redistribute it and/or |
| modify it under the terms of the GNU Lesser General Public |
| License as published by the Free Software Foundation; either |
| version 2.1 of the License, or (at your option) any later version. |
| |
| The GNU C Library is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public |
| License along with the GNU C Library; if not, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| /* Return: dest |
| |
| Inputs: |
| in0: dest |
| in1: src |
| in2: len |
| |
| In this form, it assumes little endian mode. |
| */ |
| |
| #include <sysdep.h> |
| #undef ret |
| |
| #define saved_lc r15 |
| #define saved_pr r16 |
| #define thresh r17 |
| #define dest r18 |
| #define dest2 r19 |
| #define src r20 |
| #define len r21 |
| #define asrc r22 |
| #define tmp r23 |
| #define pos r24 |
| #define w0 r25 |
| #define w1 r26 |
| #define c r27 |
| #define sh2 r28 |
| #define sh1 r29 |
| #define loopcnt r30 |
| #define value r31 |
| |
| ENTRY(strncpy) |
| .prologue |
| alloc r2 = ar.pfs, 3, 0, 29, 32 |
| |
| #define MEMLAT 2 |
| .rotr r[MEMLAT + 2] |
| .rotp p[MEMLAT + 1] |
| |
| mov ret0 = in0 // return value = dest |
| .save pr, saved_pr |
| mov saved_pr = pr // save the predicate registers |
| .save ar.lc, saved_lc |
| mov saved_lc = ar.lc // save the loop counter |
| mov ar.ec = 0 // ec is not guaranteed to |
| // be zero upon function entry |
| .body |
| cmp.geu p6, p5 = 24, in2 |
| (p6) br.cond.spnt .short_len |
| sub tmp = r0, in0 ;; // tmp = -dest |
| mov len = in2 // len |
| mov dest = in0 // dest |
| mov src = in1 // src |
| and tmp = 7, tmp ;; // loopcnt = -dest % 8 |
| cmp.eq p6, p7 = tmp, r0 |
| adds loopcnt = -1, tmp // --loopcnt |
| (p6) br.cond.sptk .dest_aligned ;; |
| sub len = len, tmp // len -= -dest % 8 |
| mov ar.lc = loopcnt |
| .l1: // copy -dest % 8 bytes |
| (p5) ld1 c = [src], 1 // c = *src++ |
| ;; |
| st1 [dest] = c, 1 // *dest++ = c |
| cmp.ne p5, p7 = c, r0 |
| br.cloop.dptk .l1 ;; |
| (p7) br.cond.dpnt .found0_align |
| |
| .dest_aligned: // p7 should be cleared here |
| shr.u c = len, 3 // c = len / 8 |
| and sh1 = 7, src // sh1 = src % 8 |
| and asrc = -8, src ;; // asrc = src & -OPSIZ -- align src |
| adds c = (MEMLAT-1), c // c = (len / 8) + MEMLAT - 1 |
| sub thresh = 8, sh1 |
| mov pr.rot = 1 << 16 // set rotating predicates |
| shl sh1 = sh1, 3 ;; // sh1 = 8 * (src % 8) |
| mov ar.lc = c // "infinite" loop |
| sub sh2 = 64, sh1 // sh2 = 64 - sh1 |
| cmp.eq p6, p0 = sh1, r0 // is the src aligned? |
| (p6) br.cond.sptk .src_aligned |
| adds c = -(MEMLAT-1), c ;; // c = (len / 8) |
| ld8 r[1] = [asrc],8 |
| mov ar.lc = c ;; |
| |
| .align 32 |
| .l2: |
| (p6) st8 [dest] = value, 8 // store val to dest |
| ld8.s r[0] = [asrc], 8 |
| shr.u value = r[1], sh1 ;; // value = w0 >> sh1 |
| czx1.r pos = value ;; // do we have an "early" zero |
| cmp.lt p7, p0 = pos, thresh // in w0 >> sh1? |
| adds len = -8, len // len -= 8 |
| (p7) br.cond.dpnt .nonalign_found0 |
| chk.s r[0], .recovery2 // it is safe to do that only |
| .back2: // after the previous test |
| shl tmp = r[0], sh2 // tmp = w1 << sh2 |
| ;; |
| or value = value, tmp ;; // value |= tmp |
| czx1.r pos = value ;; |
| cmp.ne p7, p6 = 8, pos |
| (p7) br.cond.dpnt .nonalign_found0 |
| br.ctop.dptk .l2 ;; |
| adds len = 8, len |
| br.cond.sptk .not_found0 ;; |
| .nonalign_found0: |
| cmp.gtu p6, p0 = -8, len |
| (p6) br.cond.dptk .found0 |
| adds len = 8, len |
| br.cond.sptk .not_found0 ;; |
| |
| .align 32 |
| .src_aligned: |
| .l3: |
| (p[0]) ld8.s r[0] = [src], 8 |
| (p[MEMLAT]) chk.s r[MEMLAT], .recovery3 |
| .back3: |
| (p[MEMLAT]) mov value = r[MEMLAT] |
| (p[MEMLAT]) czx1.r pos = r[MEMLAT] ;; |
| (p[MEMLAT]) cmp.ne p7, p0 = 8, pos |
| (p[MEMLAT]) adds len = -8, len // len -= 8 |
| (p7) br.cond.dpnt .found0 |
| (p[MEMLAT]) st8 [dest] = r[MEMLAT], 8 |
| br.ctop.dptk .l3 ;; |
| |
| chk.s r[MEMLAT-1], .recovery4 |
| .back4: |
| mov value = r[MEMLAT-1] |
| |
| .not_found0: |
| cmp.eq p5, p6 = len, r0 |
| adds len = -1, len |
| (p5) br.cond.dptk .restore_and_exit ;; |
| mov ar.lc = len |
| .l4: |
| (p6) extr.u c = value, 0, 8 // c = value & 0xff |
| (p6) shr.u value = value, 8 ;; |
| st1 [dest] = c, 1 |
| cmp.ne p6, p0 = c, r0 |
| br.cloop.dptk .l4 |
| br.cond.sptk .restore_and_exit |
| |
| .found0_align: |
| mov pos = 0 |
| adds len = -8, len |
| mov value = 0 ;; |
| .found0: |
| shl tmp = pos, 3 |
| shr.u loopcnt = len, 4 // loopcnt = len / 16 |
| mov c = -1 ;; |
| cmp.eq p6, p0 = loopcnt, r0 |
| adds loopcnt = -1, loopcnt |
| shl c = c, tmp ;; |
| and len = 0xf, len |
| andcm value = value, c |
| mov ar.lc = loopcnt ;; |
| cmp.le p7, p0 = 8, len |
| adds dest2 = 16, dest |
| st8 [dest] = value, 8 |
| and len = 0x7, len |
| (p6) br.cond.dpnt .l6 ;; |
| .l5: |
| st8 [dest] = r0, 16 |
| st8 [dest2] = r0, 16 |
| br.cloop.dptk .l5 ;; |
| .l6: |
| (p7) st8 [dest] = r0, 8 |
| cmp.eq p5, p0 = len, r0 |
| adds len = -1, len |
| (p5) br.cond.dptk .restore_and_exit ;; |
| mov ar.lc = len ;; |
| .l7: |
| st1 [dest] = r0, 1 |
| br.cloop.dptk .l7 ;; |
| .restore_and_exit: |
| mov ar.lc = saved_lc // restore the loop counter |
| mov pr = saved_pr, -1 // restore the predicate registers |
| br.ret.sptk.many b0 |
| |
| .short_len: |
| cmp.eq p5, p0 = in2, r0 |
| adds loopcnt = -1, in2 |
| (p5) br.cond.spnt .restore_and_exit ;; |
| mov ar.lc = loopcnt // p6 should be set when we get here |
| .l8: |
| (p6) ld1 c = [in1], 1 // c = *src++ |
| ;; |
| st1 [in0] = c, 1 // *dest++ = c |
| (p6) cmp.ne p6, p0 = c, r0 |
| br.cloop.dptk .l8 |
| ;; |
| mov ar.lc = saved_lc // restore the loop counter |
| mov pr = saved_pr, -1 // restore the predicate registers |
| br.ret.sptk.many b0 |
| .recovery2: |
| add c = 8, len |
| add tmp = -8, asrc ;; |
| cmp.gtu p8, p5 = c, thresh ;; |
| (p8) ld8 r[0] = [tmp] |
| (p5) mov r[0] = r0 |
| br.cond.sptk .back2 |
| .recovery3: |
| add tmp = -(MEMLAT + 1) * 8, src ;; |
| ld8 r[MEMLAT] = [tmp] |
| br.cond.sptk .back3 |
| .recovery4: |
| cmp.eq p5, p6 = len, r0 |
| add tmp = -MEMLAT * 8, src ;; |
| (p6) ld8 r[MEMLAT - 1] = [tmp] |
| (p5) mov r[MEMLAT - 1] = r0 |
| br.cond.sptk .back4 |
| END(strncpy) |
| libc_hidden_builtin_def (strncpy) |