| /* Optimized version of the standard bzero() function. |
| This file is part of the GNU C Library. |
| Copyright (C) 2000-2016 Free Software Foundation, Inc. |
| Contributed by Dan Pop for Itanium <Dan.Pop@cern.ch>. |
| Rewritten for McKinley by Sverre Jarp, HP Labs/CERN <Sverre.Jarp@cern.ch> |
| |
| 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: count |
| |
| The algorithm is fairly straightforward: set byte by byte until we |
| we get to a 16B-aligned address, then loop on 128 B chunks using an |
| early store as prefetching, then loop on 32B chucks, then clear remaining |
| words, finally clear remaining bytes. |
| Since a stf.spill f0 can store 16B in one go, we use this instruction |
| to get peak speed. */ |
| |
| #include <sysdep.h> |
| #undef ret |
| |
| #define dest in0 |
| #define cnt in1 |
| |
| #define tmp r31 |
| #define save_lc r30 |
| #define ptr0 r29 |
| #define ptr1 r28 |
| #define ptr2 r27 |
| #define ptr3 r26 |
| #define ptr9 r24 |
| #define loopcnt r23 |
| #define linecnt r22 |
| #define bytecnt r21 |
| |
| // This routine uses only scratch predicate registers (p6 - p15) |
| #define p_scr p6 // default register for same-cycle branches |
| #define p_unalgn p9 |
| #define p_y p11 |
| #define p_n p12 |
| #define p_yy p13 |
| #define p_nn p14 |
| |
| #define movi0 mov |
| |
| #define MIN1 15 |
| #define MIN1P1HALF 8 |
| #define LINE_SIZE 128 |
| #define LSIZE_SH 7 // shift amount |
| #define PREF_AHEAD 8 |
| |
| #define USE_FLP |
| #if defined(USE_INT) |
| #define store st8 |
| #define myval r0 |
| #elif defined(USE_FLP) |
| #define store stf8 |
| #define myval f0 |
| #endif |
| |
| .align 64 |
| ENTRY(bzero) |
| { .mmi |
| .prologue |
| alloc tmp = ar.pfs, 2, 0, 0, 0 |
| lfetch.nt1 [dest] |
| .save ar.lc, save_lc |
| movi0 save_lc = ar.lc |
| } { .mmi |
| .body |
| mov ret0 = dest // return value |
| nop.m 0 |
| cmp.eq p_scr, p0 = cnt, r0 |
| ;; } |
| { .mmi |
| and ptr2 = -(MIN1+1), dest // aligned address |
| and tmp = MIN1, dest // prepare to check for alignment |
| tbit.nz p_y, p_n = dest, 0 // Do we have an odd address? (M_B_U) |
| } { .mib |
| mov ptr1 = dest |
| nop.i 0 |
| (p_scr) br.ret.dpnt.many rp // return immediately if count = 0 |
| ;; } |
| { .mib |
| cmp.ne p_unalgn, p0 = tmp, r0 |
| } { .mib // NB: # of bytes to move is 1 |
| sub bytecnt = (MIN1+1), tmp // higher than loopcnt |
| cmp.gt p_scr, p0 = 16, cnt // is it a minimalistic task? |
| (p_scr) br.cond.dptk.many .move_bytes_unaligned // go move just a few (M_B_U) |
| ;; } |
| { .mmi |
| (p_unalgn) add ptr1 = (MIN1+1), ptr2 // after alignment |
| (p_unalgn) add ptr2 = MIN1P1HALF, ptr2 // after alignment |
| (p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 3 // should we do a st8 ? |
| ;; } |
| { .mib |
| (p_y) add cnt = -8, cnt |
| (p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 2 // should we do a st4 ? |
| } { .mib |
| (p_y) st8 [ptr2] = r0,-4 |
| (p_n) add ptr2 = 4, ptr2 |
| ;; } |
| { .mib |
| (p_yy) add cnt = -4, cnt |
| (p_unalgn) tbit.nz.unc p_y, p_n = bytecnt, 1 // should we do a st2 ? |
| } { .mib |
| (p_yy) st4 [ptr2] = r0,-2 |
| (p_nn) add ptr2 = 2, ptr2 |
| ;; } |
| { .mmi |
| mov tmp = LINE_SIZE+1 // for compare |
| (p_y) add cnt = -2, cnt |
| (p_unalgn) tbit.nz.unc p_yy, p_nn = bytecnt, 0 // should we do a st1 ? |
| } { .mmi |
| nop.m 0 |
| (p_y) st2 [ptr2] = r0,-1 |
| (p_n) add ptr2 = 1, ptr2 |
| ;; } |
| |
| { .mmi |
| (p_yy) st1 [ptr2] = r0 |
| cmp.gt p_scr, p0 = tmp, cnt // is it a minimalistic task? |
| } { .mbb |
| (p_yy) add cnt = -1, cnt |
| (p_scr) br.cond.dpnt.many .fraction_of_line // go move just a few |
| ;; } |
| { .mib |
| nop.m 0 |
| shr.u linecnt = cnt, LSIZE_SH |
| nop.b 0 |
| ;; } |
| |
| .align 32 |
| .l1b: // ------------------// L1B: store ahead into cache lines; fill later |
| { .mmi |
| and tmp = -(LINE_SIZE), cnt // compute end of range |
| mov ptr9 = ptr1 // used for prefetching |
| and cnt = (LINE_SIZE-1), cnt // remainder |
| } { .mmi |
| mov loopcnt = PREF_AHEAD-1 // default prefetch loop |
| cmp.gt p_scr, p0 = PREF_AHEAD, linecnt // check against actual value |
| ;; } |
| { .mmi |
| (p_scr) add loopcnt = -1, linecnt |
| add ptr2 = 16, ptr1 // start of stores (beyond prefetch stores) |
| add ptr1 = tmp, ptr1 // first address beyond total range |
| ;; } |
| { .mmi |
| add tmp = -1, linecnt // next loop count |
| movi0 ar.lc = loopcnt |
| ;; } |
| .pref_l1b: |
| { .mib |
| stf.spill [ptr9] = f0, 128 // Do stores one cache line apart |
| nop.i 0 |
| br.cloop.dptk.few .pref_l1b |
| ;; } |
| { .mmi |
| add ptr0 = 16, ptr2 // Two stores in parallel |
| movi0 ar.lc = tmp |
| ;; } |
| .l1bx: |
| { .mmi |
| stf.spill [ptr2] = f0, 32 |
| stf.spill [ptr0] = f0, 32 |
| ;; } |
| { .mmi |
| stf.spill [ptr2] = f0, 32 |
| stf.spill [ptr0] = f0, 32 |
| ;; } |
| { .mmi |
| stf.spill [ptr2] = f0, 32 |
| stf.spill [ptr0] = f0, 64 |
| cmp.lt p_scr, p0 = ptr9, ptr1 // do we need more prefetching? |
| ;; } |
| { .mmb |
| stf.spill [ptr2] = f0, 32 |
| (p_scr) stf.spill [ptr9] = f0, 128 |
| br.cloop.dptk.few .l1bx |
| ;; } |
| { .mib |
| cmp.gt p_scr, p0 = 8, cnt // just a few bytes left ? |
| (p_scr) br.cond.dpnt.many .move_bytes_from_alignment |
| ;; } |
| |
| .fraction_of_line: |
| { .mib |
| add ptr2 = 16, ptr1 |
| shr.u loopcnt = cnt, 5 // loopcnt = cnt / 32 |
| ;; } |
| { .mib |
| cmp.eq p_scr, p0 = loopcnt, r0 |
| add loopcnt = -1, loopcnt |
| (p_scr) br.cond.dpnt.many .store_words |
| ;; } |
| { .mib |
| and cnt = 0x1f, cnt // compute the remaining cnt |
| movi0 ar.lc = loopcnt |
| ;; } |
| .align 32 |
| .l2: // -----------------------------// L2A: store 32B in 2 cycles |
| { .mmb |
| store [ptr1] = myval, 8 |
| store [ptr2] = myval, 8 |
| ;; } { .mmb |
| store [ptr1] = myval, 24 |
| store [ptr2] = myval, 24 |
| br.cloop.dptk.many .l2 |
| ;; } |
| .store_words: |
| { .mib |
| cmp.gt p_scr, p0 = 8, cnt // just a few bytes left ? |
| (p_scr) br.cond.dpnt.many .move_bytes_from_alignment // Branch |
| ;; } |
| |
| { .mmi |
| store [ptr1] = myval, 8 // store |
| cmp.le p_y, p_n = 16, cnt // |
| add cnt = -8, cnt // subtract |
| ;; } |
| { .mmi |
| (p_y) store [ptr1] = myval, 8 // store |
| (p_y) cmp.le.unc p_yy, p_nn = 16, cnt |
| (p_y) add cnt = -8, cnt // subtract |
| ;; } |
| { .mmi // store |
| (p_yy) store [ptr1] = myval, 8 |
| (p_yy) add cnt = -8, cnt // subtract |
| ;; } |
| |
| .move_bytes_from_alignment: |
| { .mib |
| cmp.eq p_scr, p0 = cnt, r0 |
| tbit.nz.unc p_y, p0 = cnt, 2 // should we terminate with a st4 ? |
| (p_scr) br.cond.dpnt.few .restore_and_exit |
| ;; } |
| { .mib |
| (p_y) st4 [ptr1] = r0,4 |
| tbit.nz.unc p_yy, p0 = cnt, 1 // should we terminate with a st2 ? |
| ;; } |
| { .mib |
| (p_yy) st2 [ptr1] = r0,2 |
| tbit.nz.unc p_y, p0 = cnt, 0 // should we terminate with a st1 ? |
| ;; } |
| |
| { .mib |
| (p_y) st1 [ptr1] = r0 |
| ;; } |
| .restore_and_exit: |
| { .mib |
| nop.m 0 |
| movi0 ar.lc = save_lc |
| br.ret.sptk.many rp |
| ;; } |
| |
| .move_bytes_unaligned: |
| { .mmi |
| .pred.rel "mutex",p_y, p_n |
| .pred.rel "mutex",p_yy, p_nn |
| (p_n) cmp.le p_yy, p_nn = 4, cnt |
| (p_y) cmp.le p_yy, p_nn = 5, cnt |
| (p_n) add ptr2 = 2, ptr1 |
| } { .mmi |
| (p_y) add ptr2 = 3, ptr1 |
| (p_y) st1 [ptr1] = r0, 1 // fill 1 (odd-aligned) byte |
| (p_y) add cnt = -1, cnt // [15, 14 (or less) left] |
| ;; } |
| { .mmi |
| (p_yy) cmp.le.unc p_y, p0 = 8, cnt |
| add ptr3 = ptr1, cnt // prepare last store |
| movi0 ar.lc = save_lc |
| } { .mmi |
| (p_yy) st2 [ptr1] = r0, 4 // fill 2 (aligned) bytes |
| (p_yy) st2 [ptr2] = r0, 4 // fill 2 (aligned) bytes |
| (p_yy) add cnt = -4, cnt // [11, 10 (o less) left] |
| ;; } |
| { .mmi |
| (p_y) cmp.le.unc p_yy, p0 = 8, cnt |
| add ptr3 = -1, ptr3 // last store |
| tbit.nz p_scr, p0 = cnt, 1 // will there be a st2 at the end ? |
| } { .mmi |
| (p_y) st2 [ptr1] = r0, 4 // fill 2 (aligned) bytes |
| (p_y) st2 [ptr2] = r0, 4 // fill 2 (aligned) bytes |
| (p_y) add cnt = -4, cnt // [7, 6 (or less) left] |
| ;; } |
| { .mmi |
| (p_yy) st2 [ptr1] = r0, 4 // fill 2 (aligned) bytes |
| (p_yy) st2 [ptr2] = r0, 4 // fill 2 (aligned) bytes |
| // [3, 2 (or less) left] |
| tbit.nz p_y, p0 = cnt, 0 // will there be a st1 at the end ? |
| } { .mmi |
| (p_yy) add cnt = -4, cnt |
| ;; } |
| { .mmb |
| (p_scr) st2 [ptr1] = r0 // fill 2 (aligned) bytes |
| (p_y) st1 [ptr3] = r0 // fill last byte (using ptr3) |
| br.ret.sptk.many rp |
| ;; } |
| END(bzero) |