| /* A memcpy for CRIS. |
| Copyright (C) 1994-2008 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> |
| |
| #ifdef __arch_v32 |
| /* For CRISv32, movem is very cheap. */ |
| #define MEMCPY_BY_BLOCK_THRESHOLD (44) |
| #else |
| /* 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) |
| #endif |
| |
| /* No name ambiguities in this file. */ |
| __asm__ (".syntax no_register_prefix"); |
| |
| void * |
| memcpy(void *pdst, const void *psrc, size_t pn) |
| { |
| /* 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). |
| |
| 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 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. */ |
| if (((unsigned long) dst & 3) != 0 |
| /* Don't align if we wouldn't copy more than a few bytes; so we |
| don't have to check further for overflows. */ |
| && n >= 3) |
| { |
| if ((unsigned long) dst & 1) |
| { |
| n--; |
| *dst = *src; |
| src++; |
| dst++; |
| } |
| |
| if ((unsigned long) dst & 2) |
| { |
| n -= 2; |
| *(short *) dst = *(short *) src; |
| src += 2; |
| dst += 2; |
| } |
| } |
| |
| /* 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\ |
| \n\ |
| ;; Update n for the first loop. \n\ |
| subq 44,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 |
| " movem [r11+],r10 \n\ |
| subq 44,r12 \n\ |
| bge 0b \n\ |
| movem r10,[r13+] \n\ |
| \n\ |
| ;; Compensate for last loop underflowing n. \n\ |
| addq 44,r12 \n\ |
| \n\ |
| ;; Restore registers from stack. \n\ |
| movem [sp+],r10" |
| |
| /* Outputs. */ |
| : "=r" (dst), "=r" (src), "=r" (n) |
| |
| /* Inputs. */ |
| : "0" (dst), "1" (src), "2" (n)); |
| } |
| |
| 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; |
| } |
| |
| switch (n) |
| { |
| case 0: |
| break; |
| |
| case 1: |
| *dst = *src; |
| break; |
| |
| case 2: |
| *(short *) dst = *(short *) src; |
| break; |
| |
| case 3: |
| *(short *) dst = *(short *) src; dst += 2; src += 2; |
| *dst = *src; |
| break; |
| |
| case 4: |
| *(long *) dst = *(long *) src; |
| break; |
| |
| case 5: |
| *(long *) dst = *(long *) src; dst += 4; src += 4; |
| *dst = *src; |
| break; |
| |
| case 6: |
| *(long *) dst = *(long *) src; dst += 4; src += 4; |
| *(short *) dst = *(short *) src; |
| break; |
| |
| case 7: |
| *(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; dst += 4; src += 4; |
| *(long *) dst = *(long *) src; |
| break; |
| |
| case 9: |
| *(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; dst += 4; src += 4; |
| *(long *) dst = *(long *) src; dst += 4; src += 4; |
| *(short *) dst = *(short *) src; |
| break; |
| |
| case 11: |
| *(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; dst += 4; src += 4; |
| *(long *) dst = *(long *) src; dst += 4; src += 4; |
| *(long *) dst = *(long *) src; |
| break; |
| |
| case 13: |
| *(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; 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; 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; |
| } |
| libc_hidden_def(memcpy) |