/* Optimized version of the standard memset() function. This file is part of the GNU C Library. Copyright (C) 2000, 2001, 2002, 2003 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: value in2: 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 when value = 0. */ #include <sysdep.h> #undef ret #define dest in0 #define value in1 #define cnt in2 #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 #define fvalue f6 /* This routine uses only scratch predicate registers (p6 - p15) */ #define p_scr p6 /* default register for same-cycle branches */ #define p_nz p7 #define p_zr p8 #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 value #elif defined(USE_FLP) #define store stf8 #define myval fvalue #endif .align 64 ENTRY(memset) { .mmi .prologue alloc tmp = ar.pfs, 3, 0, 0, 0 lfetch.nt1 [dest] .save ar.lc, save_lc movi0 save_lc = ar.lc } { .mmi .body mov ret0 = dest /* return value */ cmp.ne p_nz, p_zr = value, r0 /* use stf.spill if value is zero */ 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 mux1 value = value, @brcst /* create 8 identical bytes in word */ (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 higher */ sub bytecnt = (MIN1+1), tmp /* 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] = value, -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] = value, -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 setf.sig fvalue=value /* transfer value to FLP side */ (p_y) st2 [ptr2] = value, -1 (p_n) add ptr2 = 1, ptr2 ;; } { .mmi (p_yy) st1 [ptr2] = value 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 (p_zr) br.cond.dptk.many .l1b /* Jump to use stf.spill */ ;; } #ifndef GAS_ALIGN_BREAKS_UNWIND_INFO .align 32 /* -------- L1A: store ahead into cache lines; fill later */ #endif { .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 /* start of stores */ add ptr2 = 8, ptr1 /* (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_l1a: { .mib store [ptr9] = myval, 128 /* Do stores one cache line apart */ nop.i 0 br.cloop.dptk.few .pref_l1a ;; } { .mmi add ptr0 = 16, ptr2 /* Two stores in parallel */ movi0 ar.lc = tmp ;; } .l1ax: { .mmi store [ptr2] = myval, 8 store [ptr0] = myval, 8 ;; } { .mmi store [ptr2] = myval, 24 store [ptr0] = myval, 24 ;; } { .mmi store [ptr2] = myval, 8 store [ptr0] = myval, 8 ;; } { .mmi store [ptr2] = myval, 24 store [ptr0] = myval, 24 ;; } { .mmi store [ptr2] = myval, 8 store [ptr0] = myval, 8 ;; } { .mmi store [ptr2] = myval, 24 store [ptr0] = myval, 24 ;; } { .mmi store [ptr2] = myval, 8 store [ptr0] = myval, 32 cmp.lt p_scr, p0 = ptr9, ptr1 /* do we need more prefetching? */ ;; } { .mmb store [ptr2] = myval, 24 (p_scr) store [ptr9] = myval, 128 br.cloop.dptk.few .l1ax ;; } { .mbb cmp.le p_scr, p0 = 8, cnt /* just a few bytes left ? */ (p_scr) br.cond.dpnt.many .fraction_of_line /* Branch no. 2 */ br.cond.dpnt.many .move_bytes_from_alignment /* Branch no. 3 */ ;; } #ifdef GAS_ALIGN_BREAKS_UNWIND_INFO { nop 0 } #else .align 32 #endif .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 ;; } #ifndef GAS_ALIGN_BREAKS_UNWIND_INFO .align 32 #endif .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] = value, 4 tbit.nz.unc p_yy, p0 = cnt, 1 /* should we terminate with a st2 ? */ ;; } { .mib (p_yy) st2 [ptr1] = value, 2 tbit.nz.unc p_y, p0 = cnt, 0 ;; } { .mib (p_y) st1 [ptr1] = value ;; } .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] = value, 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] = value, 4 /* fill 2 (aligned) bytes */ (p_yy) st2 [ptr2] = value, 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] = value, 4 /* fill 2 (aligned) bytes */ (p_y) st2 [ptr2] = value, 4 /* fill 2 (aligned) bytes */ (p_y) add cnt = -4, cnt /* [7, 6 (or less) left] */ ;; } { .mmi (p_yy) st2 [ptr1] = value, 4 /* fill 2 (aligned) bytes */ (p_yy) st2 [ptr2] = value, 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] = value /* fill 2 (aligned) bytes */ (p_y) st1 [ptr3] = value /* fill last byte (using ptr3) */ br.ret.sptk.many rp ;; } END(memset) libc_hidden_def (memset)