diff options
Diffstat (limited to 'arch/cris/arch-v10/lib/string.c')
| -rw-r--r-- | arch/cris/arch-v10/lib/string.c | 337 |
1 files changed, 174 insertions, 163 deletions
diff --git a/arch/cris/arch-v10/lib/string.c b/arch/cris/arch-v10/lib/string.c index 7161a2bef4fe..c7bd6ebdc93c 100644 --- a/arch/cris/arch-v10/lib/string.c +++ b/arch/cris/arch-v10/lib/string.c @@ -1,55 +1,59 @@ -/*#************************************************************************#*/ -/*#-------------------------------------------------------------------------*/ -/*# */ -/*# FUNCTION NAME: memcpy() */ -/*# */ -/*# PARAMETERS: void* dst; Destination address. */ -/*# void* src; Source address. */ -/*# int len; Number of bytes to copy. */ -/*# */ -/*# RETURNS: dst. */ -/*# */ -/*# DESCRIPTION: Copies len bytes of memory from src to dst. No guarantees */ -/*# about copying of overlapping memory areas. This routine is */ -/*# very sensitive to compiler changes in register allocation. */ -/*# Should really be rewritten to avoid this problem. */ -/*# */ -/*#-------------------------------------------------------------------------*/ -/*# */ -/*# HISTORY */ -/*# */ -/*# DATE NAME CHANGES */ -/*# ---- ---- ------- */ -/*# 941007 Kenny R Creation */ -/*# 941011 Kenny R Lots of optimizations and inlining. */ -/*# 941129 Ulf A Adapted for use in libc. */ -/*# 950216 HP N==0 forgotten if non-aligned src/dst. */ -/*# Added some optimizations. */ -/*# 001025 HP Make src and dst char *. Align dst to */ -/*# dword, not just word-if-both-src-and-dst- */ -/*# are-misaligned. */ -/*# */ -/*#-------------------------------------------------------------------------*/ - -#include <linux/types.h> - -void *memcpy(void *pdst, - const void *psrc, - size_t pn) +/* A memcpy for CRIS. + Copyright (C) 1994-2005 Axis Communications. + All rights reserved. + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions + are met: + + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + 2. Neither the name of Axis Communications nor the names of its + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + + THIS SOFTWARE IS PROVIDED BY AXIS COMMUNICATIONS AND ITS CONTRIBUTORS + ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL AXIS + COMMUNICATIONS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, + INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR + SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, + STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING + IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + POSSIBILITY OF SUCH DAMAGE. */ + +/* FIXME: This file should really only be used for reference, as the + result is somewhat depending on gcc generating what we expect rather + than what we describe. An assembly file should be used instead. */ + +#include <stddef.h> + +/* Break even between movem and move16 is really at 38.7 * 2, but + modulo 44, so up to the next multiple of 44, we use ordinary code. */ +#define MEMCPY_BY_BLOCK_THRESHOLD (44 * 2) + +/* No name ambiguities in this file. */ +__asm__ (".syntax no_register_prefix"); + +void * +memcpy(void *pdst, const void *psrc, size_t pn) { - /* Ok. Now we want the parameters put in special registers. + /* Now we want the parameters put in special registers. Make sure the compiler is able to make something useful of this. - As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop). + As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop). - If gcc was alright, it really would need no temporaries, and no - stack space to save stuff on. */ + If gcc was allright, it really would need no temporaries, and no + stack space to save stuff on. */ register void *return_dst __asm__ ("r10") = pdst; - register char *dst __asm__ ("r13") = pdst; - register const char *src __asm__ ("r11") = psrc; + register unsigned char *dst __asm__ ("r13") = pdst; + register unsigned const char *src __asm__ ("r11") = psrc; register int n __asm__ ("r12") = pn; - - + /* When src is aligned but not dst, this makes a few extra needless cycles. I believe it would take as many to check that the re-alignment was unnecessary. */ @@ -59,167 +63,174 @@ void *memcpy(void *pdst, && n >= 3) { if ((unsigned long) dst & 1) - { - n--; - *(char*)dst = *(char*)src; - src++; - dst++; - } + { + n--; + *dst = *src; + src++; + dst++; + } if ((unsigned long) dst & 2) - { - n -= 2; - *(short*)dst = *(short*)src; - src += 2; - dst += 2; - } + { + n -= 2; + *(short *) dst = *(short *) src; + src += 2; + dst += 2; + } } - /* Decide which copying method to use. */ - if (n >= 44*2) /* Break even between movem and - move16 is at 38.7*2, but modulo 44. */ - { - /* 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. - - If you want to check that the allocation was right; then - check the equalities in the first comment. It should say - "r13=r13, r11=r11, r12=r12" */ - __asm__ volatile ("\n\ - ;; Check that the following is true (same register names on \n\ - ;; both sides of equal sign, as in r8=r8): \n\ - ;; %0=r13, %1=r11, %2=r12 \n\ - ;; \n\ - ;; Save the registers we'll use in the movem process \n\ - ;; on the stack. \n\ - subq 11*4,$sp \n\ - movem $r10,[$sp] \n\ + /* Decide which copying method to use. */ + if (n >= MEMCPY_BY_BLOCK_THRESHOLD) + { + /* 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. */ + __asm__ volatile + ("\ + ;; GCC does promise correct register allocations, but let's \n\ + ;; make sure it keeps its promises. \n\ + .ifnc %0-%1-%2,$r13-$r11-$r12 \n\ + .error \"GCC reg alloc bug: %0-%1-%4 != $r13-$r12-$r11\" \n\ + .endif \n\ + \n\ + ;; Save the registers we'll use in the movem process \n\ + ;; on the stack. \n\ + subq 11*4,sp \n\ + movem r10,[sp] \n\ \n\ - ;; Now we've got this: \n\ - ;; r11 - src \n\ - ;; r13 - dst \n\ - ;; r12 - n \n\ + ;; Now we've got this: \n\ + ;; r11 - src \n\ + ;; r13 - dst \n\ + ;; r12 - n \n\ \n\ - ;; Update n for the first loop \n\ - subq 44,$r12 \n\ + ;; Update n for the first loop. \n\ + subq 44,r12 \n\ 0: \n\ - movem [$r11+],$r10 \n\ - subq 44,$r12 \n\ - bge 0b \n\ - movem $r10,[$r13+] \n\ +" +#ifdef __arch_common_v10_v32 + /* Cater to branch offset difference between v32 and v10. We + assume the branch below has an 8-bit offset. */ +" setf\n" +#endif +" movem [r11+],r10 \n\ + subq 44,r12 \n\ + bge 0b \n\ + movem r10,[r13+] \n\ \n\ - addq 44,$r12 ;; compensate for last loop underflowing n \n\ + ;; Compensate for last loop underflowing n. \n\ + addq 44,r12 \n\ \n\ - ;; Restore registers from stack \n\ - movem [$sp+],$r10" + ;; Restore registers from stack. \n\ + movem [sp+],r10" - /* Outputs */ : "=r" (dst), "=r" (src), "=r" (n) - /* Inputs */ : "0" (dst), "1" (src), "2" (n)); - - } + /* Outputs. */ + : "=r" (dst), "=r" (src), "=r" (n) - /* 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. */ + /* Inputs. */ + : "0" (dst), "1" (src), "2" (n)); + } - while ( n >= 16 ) - { - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - n -= 16; - } + while (n >= 16) + { + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + + 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*)src; + *dst = *src; break; + case 2: - *(short*)dst = *(short*)src; + *(short *) dst = *(short *) src; break; + case 3: - *((short*)dst)++ = *((short*)src)++; - *(char*)dst = *(char*)src; + *(short *) dst = *(short *) src; dst += 2; src += 2; + *dst = *src; break; + case 4: - *((long*)dst)++ = *((long*)src)++; + *(long *) dst = *(long *) src; break; + case 5: - *((long*)dst)++ = *((long*)src)++; - *(char*)dst = *(char*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *dst = *src; break; + case 6: - *((long*)dst)++ = *((long*)src)++; - *(short*)dst = *(short*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(short *) dst = *(short *) src; break; + case 7: - *((long*)dst)++ = *((long*)src)++; - *((short*)dst)++ = *((short*)src)++; - *(char*)dst = *(char*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(short *) dst = *(short *) src; dst += 2; src += 2; + *dst = *src; break; + case 8: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; break; + case 9: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *(char*)dst = *(char*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *dst = *src; break; + case 10: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *(short*)dst = *(short*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(short *) dst = *(short *) src; break; + case 11: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((short*)dst)++ = *((short*)src)++; - *(char*)dst = *(char*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(short *) dst = *(short *) src; dst += 2; src += 2; + *dst = *src; break; + case 12: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; break; + case 13: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *(char*)dst = *(char*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *dst = *src; break; + case 14: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *(short*)dst = *(short*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(short *) dst = *(short *) src; break; + case 15: - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((long*)dst)++ = *((long*)src)++; - *((short*)dst)++ = *((short*)src)++; - *(char*)dst = *(char*)src; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(long *) dst = *(long *) src; dst += 4; src += 4; + *(short *) dst = *(short *) src; dst += 2; src += 2; + *dst = *src; break; - } + } - return return_dst; /* destination pointer. */ -} /* memcpy() */ + return return_dst; +} |