diff options
Diffstat (limited to 'arch/cris/arch-v10/lib/memset.c')
| -rw-r--r-- | arch/cris/arch-v10/lib/memset.c | 397 |
1 files changed, 202 insertions, 195 deletions
diff --git a/arch/cris/arch-v10/lib/memset.c b/arch/cris/arch-v10/lib/memset.c index 42c1101043a3..c94ea9b3ec29 100644 --- a/arch/cris/arch-v10/lib/memset.c +++ b/arch/cris/arch-v10/lib/memset.c @@ -1,252 +1,259 @@ -/*#************************************************************************#*/ -/*#-------------------------------------------------------------------------*/ -/*# */ -/*# 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. */ -/*# */ -/*#-------------------------------------------------------------------------*/ - -#include <linux/types.h> - -/* 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 *pdst, - int c, - size_t plen) +/* A memset for CRIS. + Copyright (C) 1999-2005 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. */ + +/* Note the multiple occurrence of the expression "12*4", including the + asm. It is hard to get it into the asm in a good way. Thus better to + expose the problem everywhere: no macro. */ + +/* Assuming one cycle per dword written or read (ok, not really true; the + world is not ideal), and one cycle 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 MEMSET_BY_BLOCK_THRESHOLD (1 * 48) + +/* No name ambiguities in this file. */ +__asm__ (".syntax no_register_prefix"); + +void *memset(void *pdst, int c, unsigned int plen) { - /* Ok. Now we want the parameters put in special registers. - Make sure the compiler is able to make something useful of this. */ + /* Now we want the parameters in special registers. Make sure the + compiler does something usable with this. */ register char *return_dst __asm__ ("r10") = pdst; register int 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. */ + /* Most apps use memset sanely. Memsetting about 3..4 bytes or less get + penalized here compared to the generic implementation. */ - /* Ugh. This is fragile at best. Check with newer GCC releases, if - they compile cascaded "x |= x << 8" sanely! */ - __asm__("movu.b %0,$r13\n\t" - "lslq 8,$r13\n\t" - "move.b %0,$r13\n\t" - "move.d $r13,%0\n\t" - "lslq 16,$r13\n\t" - "or.d $r13,%0" - : "=r" (lc) : "0" (lc) : "r13"); + /* This is fragile performancewise at best. Check with newer GCC + releases, if they compile cascaded "x |= x << 8" to sane code. */ + __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) /* Inputs. */ + : "0" (lc) /* Outputs. */ + : "r13"); /* Trash. */ { register char *dst __asm__ ("r13") = pdst; - /* This is NONPORTABLE, but since this whole routine is */ - /* grossly nonportable that doesn't matter. */ + if (((unsigned long) pdst & 3) != 0 + /* Oops! n = 0 must be a valid call, regardless of alignment. */ + && n >= 3) + { + if ((unsigned long) dst & 1) + { + *dst = (char) lc; + n--; + dst++; + } - 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; - } - } + 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. - - If you want to check that the allocation was right; then - check the equalities in the first comment. It should say - "r13=r13, r12=r12, r11=r11" */ - __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=r12, %4=r11 \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\ + /* Decide which setting method to use. */ + if (n >= MEMSET_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-block sizes + suboptimal. */ + __asm__ volatile + ("\ + ;; GCC does promise correct register allocations, but let's \n\ + ;; make sure it keeps its promises. \n\ + .ifnc %0-%1-%4,$r13-$r12-$r11 \n\ + .error \"GCC reg alloc bug: %0-%1-%4 != $r13-$r12-$r11\" \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\ + 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\ + ;; Now we've got this: \n\ + ;; r13 - dst \n\ + ;; r12 - n \n\ \n\ - ;; Update n for the first loop \n\ - subq 12*4,$r12 \n\ + ;; Update n for the first loop \n\ + subq 12*4,r12 \n\ 0: \n\ - subq 12*4,$r12 \n\ - bge 0b \n\ - movem $r11,[$r13+] \n\ +" +#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 +" subq 12*4,r12 \n\ + bge 0b \n\ + movem r11,[r13+] \n\ \n\ - addq 12*4,$r12 ;; compensate for last loop underflowing n \n\ + ;; Compensate for last loop underflowing n. \n\ + addq 12*4,r12 \n\ \n\ - ;; Restore registers from stack \n\ - movem [$sp+],$r10" + ;; Restore registers from stack. \n\ + movem [sp+],r10" - /* Outputs */ : "=r" (dst), "=r" (n) - /* Inputs */ : "0" (dst), "1" (n), "r" (lc)); + /* Outputs. */ + : "=r" (dst), "=r" (n) - } + /* Inputs. */ + : "0" (dst), "1" (n), "r" (lc)); + } + + /* An ad-hoc unroll, used for 4*12-1..16 bytes. */ + while (n >= 16) + { + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + n -= 16; + } - /* 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; + *dst = (char) lc; break; + case 2: - *(short*)dst = (short) lc; + *(short *) dst = (short) lc; break; + case 3: - *((short*)dst)++ = (short) lc; - *(char*)dst = (char) lc; + *(short *) dst = (short) lc; dst += 2; + *dst = (char) lc; break; + case 4: - *((long*)dst)++ = lc; + *(long *) dst = lc; break; + case 5: - *((long*)dst)++ = lc; - *(char*)dst = (char) lc; + *(long *) dst = lc; dst += 4; + *dst = (char) lc; break; + case 6: - *((long*)dst)++ = lc; - *(short*)dst = (short) lc; + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; break; + case 7: - *((long*)dst)++ = lc; - *((short*)dst)++ = (short) lc; - *(char*)dst = (char) lc; + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; dst += 2; + *dst = (char) lc; break; + case 8: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; break; + case 9: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *(char*)dst = (char) lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *dst = (char) lc; break; + case 10: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *(short*)dst = (short) lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; break; + case 11: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *((short*)dst)++ = (short) lc; - *(char*)dst = (char) lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; dst += 2; + *dst = (char) lc; break; + case 12: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; break; + case 13: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *(char*)dst = (char) lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *dst = (char) lc; break; + case 14: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *(short*)dst = (short) lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; break; + case 15: - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *((long*)dst)++ = lc; - *((short*)dst)++ = (short) lc; - *(char*)dst = (char) lc; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; dst += 2; + *dst = (char) lc; break; - } + } } - return return_dst; /* destination pointer. */ -} /* memset() */ + return return_dst; +} |