diff options
Diffstat (limited to 'kernel/arch/cris/arch-v32/lib/memset.c')
| -rw-r--r-- | kernel/arch/cris/arch-v32/lib/memset.c | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/kernel/arch/cris/arch-v32/lib/memset.c b/kernel/arch/cris/arch-v32/lib/memset.c new file mode 100644 index 000000000..c94ea9b3e --- /dev/null +++ b/kernel/arch/cris/arch-v32/lib/memset.c @@ -0,0 +1,259 @@ +/* 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) +{ + /* 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. Memsetting about 3..4 bytes or less get + penalized here compared to the generic implementation. */ + + /* 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; + + 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) dst & 2) + { + *(short *) dst = lc; + n -= 2; + dst += 2; + } + } + + /* 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\ + \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\ +" +#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\ + ;; Compensate for last loop underflowing n. \n\ + addq 12*4,r12 \n\ + \n\ + ;; Restore registers from stack. \n\ + movem [sp+],r10" + + /* 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; + } + + switch (n) + { + case 0: + break; + + case 1: + *dst = (char) lc; + break; + + case 2: + *(short *) dst = (short) lc; + break; + + case 3: + *(short *) dst = (short) lc; dst += 2; + *dst = (char) lc; + break; + + case 4: + *(long *) dst = lc; + break; + + case 5: + *(long *) dst = lc; dst += 4; + *dst = (char) lc; + break; + + case 6: + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; + break; + + case 7: + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; dst += 2; + *dst = (char) lc; + break; + + case 8: + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; + break; + + case 9: + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *dst = (char) lc; + break; + + case 10: + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(short *) dst = (short) lc; + break; + + case 11: + *(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; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; + break; + + case 13: + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *(long *) dst = lc; dst += 4; + *dst = (char) lc; + break; + + case 14: + *(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; 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; +} |