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| author | Carmelo Amoroso <carmelo.amoroso@st.com> | 2008-03-16 09:11:31 +0000 | 
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| committer | Carmelo Amoroso <carmelo.amoroso@st.com> | 2008-03-16 09:11:31 +0000 | 
| commit | 1cd785fe106389b7cc708d1c413eb8bfbc95ff43 (patch) | |
| tree | 01a20f24c6cac36568a0c96ce76578fe8b8f47f8 /libc/string/cris/memset.c | |
| parent | b892d0f9caca5d891d7ce615e3df518b3870b36b (diff) | |
| download | uClibc-alpine-1cd785fe106389b7cc708d1c413eb8bfbc95ff43.tar.bz2 uClibc-alpine-1cd785fe106389b7cc708d1c413eb8bfbc95ff43.tar.xz  | |
Merge nptl branch tree with trunk. 
Step 8: add xtensa, cris and avr32 architecture dependent
files, as is.
Signed-off-by: Carmelo Amoroso <carmelo.amoroso@st.com>
Diffstat (limited to 'libc/string/cris/memset.c')
| -rw-r--r-- | libc/string/cris/memset.c | 271 | 
1 files changed, 271 insertions, 0 deletions
diff --git a/libc/string/cris/memset.c b/libc/string/cris/memset.c new file mode 100644 index 000000000..7e71bc50f --- /dev/null +++ b/libc/string/cris/memset.c @@ -0,0 +1,271 @@ +/* Copyright (C) 2001, 2003 Free Software Foundation, Inc. +   Copyright (C) 1999, 2000 Axis Communications AB. + +   This file is part of the GNU C Library. + +   The GNU C Library is free software; you can redistribute it and/or +   modify it under the terms of the GNU Library General Public License as +   published by the Free Software Foundation; either version 2 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 +   Library General Public License for more details. + +   You should have received a copy of the GNU Library General Public +   License along with the GNU C Library; see the file COPYING.LIB.  If not, +   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, +   Boston, MA 02111-1307, USA.  */ + +/*#************************************************************************#*/ +/*#-------------------------------------------------------------------------*/ +/*#                                                                         */ +/*# FUNCTION NAME: memset()                                                 */ +/*#                                                                         */ +/*# PARAMETERS:  void* dst;   Destination address.                          */ +/*#              int     c;   Value of byte to write.                       */ +/*#              int   len;   Number of bytes to write.                     */ +/*#                                                                         */ +/*# RETURNS:     dst.                                                       */ +/*#                                                                         */ +/*# DESCRIPTION: Sets the memory dst of length len bytes to c, as standard. */ +/*#              Framework taken from memcpy.  This routine is              */ +/*#              very sensitive to compiler changes in register allocation. */ +/*#              Should really be rewritten to avoid this problem.          */ +/*#                                                                         */ +/*#-------------------------------------------------------------------------*/ +/*#                                                                         */ +/*# HISTORY                                                                 */ +/*#                                                                         */ +/*# DATE      NAME            CHANGES                                       */ +/*# ----      ----            -------                                       */ +/*# 990713    HP              Tired of watching this function (or           */ +/*#                           really, the nonoptimized generic              */ +/*#                           implementation) take up 90% of simulator      */ +/*#                           output.  Measurements needed.                 */ +/*#                                                                         */ +/*#-------------------------------------------------------------------------*/ + +/* No, there's no macro saying 12*4, since it is "hard" to get it into +   the asm in a good way.  Thus better to expose the problem everywhere. +   */ + +/* Assuming 1 cycle per dword written or read (ok, not really true), and +   one per instruction, then 43+3*(n/48-1) <= 24+24*(n/48-1) +   so n >= 45.7; n >= 0.9; we win on the first full 48-byte block to set. */ + +#define ZERO_BLOCK_SIZE (1*12*4) + +void *memset(void *, int, unsigned long); + +libc_hidden_proto(memset) +void *memset(void *pdst, +             int c, +             unsigned long plen) +{ +  /* Ok.  Now we want the parameters put in special registers. +     Make sure the compiler is able to make something useful of this. */ + +  register char *return_dst __asm__ ("r10") = pdst; +  register long n __asm__ ("r12") = plen; +  register int lc __asm__ ("r11") = c; + +  /* Most apps use memset sanely.  Only those memsetting about 3..4 +     bytes or less get penalized compared to the generic implementation +     - and that's not really sane use. */ + +  /* Ugh.  This is fragile at best.  Check with newer GCC releases, if +     they compile cascaded "x |= x << 8" sanely! */ +  __asm__("movu.b %0,$r13 \n\ +	   lslq 8,$r13    \n\ +	   move.b %0,$r13 \n\ +	   move.d $r13,%0 \n\ +	   lslq 16,$r13   \n\ +	   or.d $r13,%0" +          : "=r" (lc) : "0" (lc) : "r13"); + +  { +    register char *dst __asm__ ("r13") = pdst; +  +  if (((unsigned long) pdst & 3) != 0 +     /* Oops! n=0 must be a legal call, regardless of alignment. */ +      && n >= 3) +  { +    if ((unsigned long)dst & 1) +    { +      *dst = (char) lc; +      n--; +      dst++; +    } + +    if ((unsigned long)dst & 2) +    { +      *(short *)dst = lc; +      n -= 2; +      dst += 2; +    } +  } + +  /* Now the fun part.  For the threshold value of this, check the equation +     above. */ +  /* Decide which copying method to use. */ +  if (n >= ZERO_BLOCK_SIZE) +  { +    /* For large copies we use 'movem' */ + +  /* It is not optimal to tell the compiler about clobbering any +     registers; that will move the saving/restoring of those registers +     to the function prologue/epilogue, and make non-movem sizes +     suboptimal. + +      This method is not foolproof; it assumes that the "asm reg" +     declarations at the beginning of the function really are used +     here (beware: they may be moved to temporary registers). +      This way, we do not have to save/move the registers around into +     temporaries; we can safely use them straight away.  */ +    __asm__ volatile ("								\n\ +	.syntax no_register_prefix						\n\ +										\n\ +        ;; Check that the register asm declaration got right.			\n\ +        ;; The GCC manual explicitly says there's no warranty for that (too).	\n\ +	.ifnc %0-%1-%4,$r13-$r12-$r11						\n\ +	.err									\n\ +	.endif									\n\ +										\n\ +	;; Save the registers we'll clobber in the movem process		\n\ +	;; on the stack.  Don't mention them to gcc, it will only be		\n\ +	;; upset.								\n\ +	subq 	11*4,sp								\n\ +        movem   r10,[sp]							\n\ +										\n\ +        move.d  r11,r0								\n\ +        move.d  r11,r1								\n\ +        move.d  r11,r2								\n\ +        move.d  r11,r3								\n\ +        move.d  r11,r4								\n\ +        move.d  r11,r5								\n\ +        move.d  r11,r6								\n\ +        move.d  r11,r7								\n\ +        move.d  r11,r8								\n\ +        move.d  r11,r9								\n\ +        move.d  r11,r10								\n\ +										\n\ +        ;; Now we've got this:							\n\ +	;; r13 - dst								\n\ +	;; r12 - n								\n\ +										\n\ +        ;; Update n for the first loop						\n\ +        subq    12*4,r12							\n\ +0:										\n\ +        subq   12*4,r12								\n\ +        bge     0b								\n\ +	movem	r11,[r13+]							\n\ +										\n\ +        addq   12*4,r12  ;; compensate for last loop underflowing n		\n\ +										\n\ +	;; Restore registers from stack						\n\ +        movem [sp+],r10"  + +     /* Outputs */ : "=r" (dst), "=r" (n) +     /* Inputs */ : "0" (dst), "1" (n), "r" (lc)); +     +  } + +    /* Either we directly starts copying, using dword copying +       in a loop, or we copy as much as possible with 'movem'  +       and then the last block (<44 bytes) is copied here. +       This will work since 'movem' will have updated src,dst,n. */ + +    while ( n >= 16 ) +    { +      *((long*)dst)++ = lc; +      *((long*)dst)++ = lc; +      *((long*)dst)++ = lc; +      *((long*)dst)++ = lc; +      n -= 16; +    } + +    /* A switch() is definitely the fastest although it takes a LOT of code. +     * Particularly if you inline code this. +     */ +    switch (n) +    { +      case 0: +        break; +      case 1: +        *(char*)dst = (char) lc; +        break; +      case 2: +        *(short*)dst = (short) lc; +        break; +      case 3: +        *((short*)dst)++ = (short) lc; +        *(char*)dst = (char) lc; +        break; +      case 4: +        *((long*)dst)++ = lc; +        break; +      case 5: +        *((long*)dst)++ = lc; +        *(char*)dst = (char) lc; +        break; +      case 6: +        *((long*)dst)++ = lc; +        *(short*)dst = (short) lc; +        break; +      case 7: +        *((long*)dst)++ = lc; +        *((short*)dst)++ = (short) lc; +        *(char*)dst = (char) lc; +        break; +      case 8: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        break; +      case 9: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *(char*)dst = (char) lc; +        break; +      case 10: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *(short*)dst = (short) lc; +        break; +      case 11: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *((short*)dst)++ = (short) lc; +        *(char*)dst = (char) lc; +        break; +      case 12: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        break; +      case 13: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *(char*)dst = (char) lc; +        break; +      case 14: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *(short*)dst = (short) lc; +        break; +      case 15: +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *((long*)dst)++ = lc; +        *((short*)dst)++ = (short) lc; +        *(char*)dst = (char) lc; +        break; +    } +  } + +  return return_dst; /* destination pointer. */ +} /* memset() */ +libc_hidden_def(memset)  | 
