glibc/sysdeps/ia64/bzero.S

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/* 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
Prefer https to http for gnu.org and fsf.org URLs Also, change sources.redhat.com to sourceware.org. This patch was automatically generated by running the following shell script, which uses GNU sed, and which avoids modifying files imported from upstream: sed -ri ' s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g ' \ $(find $(git ls-files) -prune -type f \ ! -name '*.po' \ ! -name 'ChangeLog*' \ ! -path COPYING ! -path COPYING.LIB \ ! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \ ! -path manual/texinfo.tex ! -path scripts/config.guess \ ! -path scripts/config.sub ! -path scripts/install-sh \ ! -path scripts/mkinstalldirs ! -path scripts/move-if-change \ ! -path INSTALL ! -path locale/programs/charmap-kw.h \ ! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \ ! '(' -name configure \ -execdir test -f configure.ac -o -f configure.in ';' ')' \ ! '(' -name preconfigure \ -execdir test -f preconfigure.ac ';' ')' \ -print) and then by running 'make dist-prepare' to regenerate files built from the altered files, and then executing the following to cleanup: chmod a+x sysdeps/unix/sysv/linux/riscv/configure # Omit irrelevant whitespace and comment-only changes, # perhaps from a slightly-different Autoconf version. git checkout -f \ sysdeps/csky/configure \ sysdeps/hppa/configure \ sysdeps/riscv/configure \ sysdeps/unix/sysv/linux/csky/configure # Omit changes that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines git checkout -f \ sysdeps/powerpc/powerpc64/ppc-mcount.S \ sysdeps/unix/sysv/linux/s390/s390-64/syscall.S # Omit change that caused a pre-commit check to fail like this: # remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
2019-09-07 05:40:42 +00:00
<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
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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
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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)