+++ /dev/null
-/* Optimized version of the standard bzero() function.
- This file is part of the GNU C Library.
- Copyright (C) 2000-2022 Free Software Foundation, Inc.
-
- 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
- <https://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)
projects / thirdparty / glibc.git / commitdiff
