| /* A memset for CRIS. |
| Copyright (C) 1999-2008 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 <string.h> |
| |
| /* 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; |
| } |
| libc_hidden_def(memset) |