Skip to content

L
linux
Commit 9fe3fd03 authored by Jesper Nilsson's avatar Jesper Nilsson Committed by Linus Torvalds
Browse files
Options

CRIS: Import string.c (memcpy) from newlib: fixes compile error with gcc 4 

Adrian Bunk reported another compile error with a SVN head GCC:

...
  CC      arch/cris/arch-v10/lib/string.o
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/string.c:138:
error: lvalue required as increment operand
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/string.c:138:
error: lvalue required as increment operand
/home/bunk/linux/kernel-2.6/git/linux-2.6/arch/cris/arch-v10/lib/string.c:139:
error: lvalue required as increment operand
...

This is due to the use of the construct:

	*((long*)dst)++ = lc;

Which isn't legal since casts don't return an lvalue.

The solution is to import the implementation from newlib,
which is continually autotested together with GCC mainline,
and uses the construct:

	*(long *) dst = lc; dst += 4;

Since this is an import of a file from newlib, I'm not touching
the formatting or correcting any checkpatch errors.

As for the earlier fix for memset.c, even if the two files for
CRIS v10 and CRIS v32 are identical at the moment, it might
be possible to tweak the CRIS v32 version.
Thus, I'm not yet folding them into the same file, at least not
until we've done some research on it.
Signed-off-by: default avatarJesper Nilsson <jesper.nilsson@axis.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a51f4124
Show whitespace changes
Inline Side-by-side
Showing with 345 additions and 317 deletions
arch/cris/arch-v10/lib/string.c
View file @ 9fe3fd03
/*#************************************************************************#*/ /* A memcpy for CRIS.
/*#-------------------------------------------------------------------------*/ Copyright (C) 1994-2005 Axis Communications.
/*# */ All rights reserved.
/*# FUNCTION NAME: memcpy() */
/*# */ Redistribution and use in source and binary forms, with or without
/*# PARAMETERS: void* dst; Destination address. */ modification, are permitted provided that the following conditions
/*# void* src; Source address. */ are met:
/*# int len; Number of bytes to copy. */
/*# */ 1. Redistributions of source code must retain the above copyright
/*# RETURNS: dst. */ notice, this list of conditions and the following disclaimer.
/*# */
/*# DESCRIPTION: Copies len bytes of memory from src to dst. No guarantees */ 2. Neither the name of Axis Communications nor the names of its
/*# about copying of overlapping memory areas. This routine is */ contributors may be used to endorse or promote products derived
/*# very sensitive to compiler changes in register allocation. */ from this software without specific prior written permission.
/*# Should really be rewritten to avoid this problem. */
/*# */ 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
/*# HISTORY */ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL AXIS
/*# */ COMMUNICATIONS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
/*# DATE NAME CHANGES */ INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
/*# ---- ---- ------- */ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
/*# 941007 Kenny R Creation */ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
/*# 941011 Kenny R Lots of optimizations and inlining. */ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
/*# 941129 Ulf A Adapted for use in libc. */ STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
/*# 950216 HP N==0 forgotten if non-aligned src/dst. */ IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
/*# Added some optimizations. */ POSSIBILITY OF SUCH DAMAGE. */
/*# 001025 HP Make src and dst char *. Align dst to */
/*# dword, not just word-if-both-src-and-dst- */ /* FIXME: This file should really only be used for reference, as the
/*# are-misaligned. */ 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>
#include <linux/types.h>
/* Break even between movem and move16 is really at 38.7 * 2, but
void *memcpy(void *pdst, modulo 44, so up to the next multiple of 44, we use ordinary code. */
const void *psrc, #define MEMCPY_BY_BLOCK_THRESHOLD (44 * 2)
size_t pn)
/* 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. 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 If gcc was allright, it really would need no temporaries, and no
stack space to save stuff on. */ stack space to save stuff on. */
register void *return_dst __asm__ ("r10") = pdst; register void *return_dst __asm__ ("r10") = pdst;
register char *dst __asm__ ("r13") = pdst; register unsigned char *dst __asm__ ("r13") = pdst;
register const char *src __asm__ ("r11") = psrc; register unsigned const char *src __asm__ ("r11") = psrc;
register int n __asm__ ("r12") = pn; register int n __asm__ ("r12") = pn;
/* When src is aligned but not dst, this makes a few extra needless /* 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 cycles. I believe it would take as many to check that the
re-alignment was unnecessary. */ re-alignment was unnecessary. */
...@@ -61,7 +65,7 @@ void *memcpy(void *pdst, ...@@ -61,7 +65,7 @@ void *memcpy(void *pdst,
if ((unsigned long) dst & 1) if ((unsigned long) dst & 1)
{ {
n--; n--;
*(char*)dst = *(char*)src; *dst = *src;
src++; src++;
dst++; dst++;
} }
...@@ -69,157 +73,164 @@ void *memcpy(void *pdst, ...@@ -69,157 +73,164 @@ void *memcpy(void *pdst,
if ((unsigned long) dst & 2) if ((unsigned long) dst & 2)
{ {
n -= 2; n -= 2;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
src += 2; src += 2;
dst += 2; dst += 2;
} }
} }
/* Decide which copying method to use. */ /* Decide which copying method to use. */
if (n >= 44*2) /* Break even between movem and if (n >= MEMCPY_BY_BLOCK_THRESHOLD)
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 /* It is not optimal to tell the compiler about clobbering any
registers; that will move the saving/restoring of those registers registers; that will move the saving/restoring of those registers
to the function prologue/epilogue, and make non-movem sizes to the function prologue/epilogue, and make non-movem sizes
suboptimal. suboptimal. */
__asm__ volatile
This method is not foolproof; it assumes that the "asm reg" ("\
declarations at the beginning of the function really are used ;; GCC does promise correct register allocations, but let's \n\
here (beware: they may be moved to temporary registers). ;; make sure it keeps its promises. \n\
This way, we do not have to save/move the registers around into .ifnc %0-%1-%2,$r13-$r11-$r12 \n\
temporaries; we can safely use them straight away. .error \"GCC reg alloc bug: %0-%1-%4 != $r13-$r12-$r11\" \n\
.endif \n\
If you want to check that the allocation was right; then \n\
check the equalities in the first comment. It should say
"r13=r13, r11=r11, r12=r12" */
__asm__ volatile ("\n\
;; Check that the following is true (same register names on \n\
;; both sides of equal sign, as in r8=r8): \n\
;; %0=r13, %1=r11, %2=r12 \n\
;; \n\
;; Save the registers we'll use in the movem process \n\ ;; Save the registers we'll use in the movem process \n\
;; on the stack. \n\ ;; on the stack. \n\
subq 11*4,$sp \n\ subq 11*4,sp \n\
movem $r10,[$sp] \n\ movem r10,[sp] \n\
\n\ \n\
;; Now we've got this: \n\ ;; Now we've got this: \n\
;; r11 - src \n\ ;; r11 - src \n\
;; r13 - dst \n\ ;; r13 - dst \n\
;; r12 - n \n\ ;; r12 - n \n\
\n\ \n\
;; Update n for the first loop \n\ ;; Update n for the first loop. \n\
subq 44,$r12 \n\ subq 44,r12 \n\
0: \n\ 0: \n\
movem [$r11+],$r10 \n\ "
subq 44,$r12 \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\ bge 0b \n\
movem $r10,[$r13+] \n\ movem r10,[r13+] \n\
\n\ \n\
addq 44,$r12 ;; compensate for last loop underflowing n \n\ ;; Compensate for last loop underflowing n. \n\
addq 44,r12 \n\
\n\ \n\
;; Restore registers from stack \n\ ;; Restore registers from stack. \n\
movem [$sp+],$r10" movem [sp+],r10"
/* Outputs */ : "=r" (dst), "=r" (src), "=r" (n) /* Outputs. */
/* Inputs */ : "0" (dst), "1" (src), "2" (n)); : "=r" (dst), "=r" (src), "=r" (n)
/* Inputs. */
: "0" (dst), "1" (src), "2" (n));
} }
/* Either we directly starts copying, using dword copying while (n >= 16)
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)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
n -= 16; n -= 16;
} }
/* A switch() is definitely the fastest although it takes a LOT of code.
* Particularly if you inline code this.
*/
switch (n) switch (n)
{ {
case 0: case 0:
break; break;
case 1: case 1:
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 2: case 2:
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 3: case 3:
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 4: case 4:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src;
break; break;
case 5: case 5:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 6: case 6:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 7: case 7:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 8: case 8:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src;
break; break;
case 9: case 9:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 10: case 10:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 11: case 11:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 12: case 12:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src;
break; break;
case 13: case 13:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 14: case 14:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 15: case 15:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
} }
return return_dst; /* destination pointer. */ return return_dst;
} /* memcpy() */ }
arch/cris/arch-v32/lib/string.c
View file @ 9fe3fd03
/*#************************************************************************#*/ /* A memcpy for CRIS.
/*#-------------------------------------------------------------------------*/ Copyright (C) 1994-2005 Axis Communications.
/*# */ All rights reserved.
/*# FUNCTION NAME: memcpy() */
/*# */ Redistribution and use in source and binary forms, with or without
/*# PARAMETERS: void* dst; Destination address. */ modification, are permitted provided that the following conditions
/*# void* src; Source address. */ are met:
/*# int len; Number of bytes to copy. */
/*# */ 1. Redistributions of source code must retain the above copyright
/*# RETURNS: dst. */ notice, this list of conditions and the following disclaimer.
/*# */
/*# DESCRIPTION: Copies len bytes of memory from src to dst. No guarantees */ 2. Neither the name of Axis Communications nor the names of its
/*# about copying of overlapping memory areas. This routine is */ contributors may be used to endorse or promote products derived
/*# very sensitive to compiler changes in register allocation. */ from this software without specific prior written permission.
/*# Should really be rewritten to avoid this problem. */
/*# */ 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
/*# HISTORY */ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL AXIS
/*# */ COMMUNICATIONS OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
/*# DATE NAME CHANGES */ INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
/*# ---- ---- ------- */ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
/*# 941007 Kenny R Creation */ SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
/*# 941011 Kenny R Lots of optimizations and inlining. */ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
/*# 941129 Ulf A Adapted for use in libc. */ STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
/*# 950216 HP N==0 forgotten if non-aligned src/dst. */ IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
/*# Added some optimizations. */ POSSIBILITY OF SUCH DAMAGE. */
/*# 001025 HP Make src and dst char *. Align dst to */
/*# dword, not just word-if-both-src-and-dst- */ /* FIXME: This file should really only be used for reference, as the
/*# are-misaligned. */ 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>
#include <linux/types.h>
/* Break even between movem and move16 is really at 38.7 * 2, but
void *memcpy(void *pdst, modulo 44, so up to the next multiple of 44, we use ordinary code. */
const void *psrc, #define MEMCPY_BY_BLOCK_THRESHOLD (44 * 2)
size_t pn)
/* 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. 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 If gcc was allright, it really would need no temporaries, and no
stack space to save stuff on. */ stack space to save stuff on. */
register void *return_dst __asm__ ("r10") = pdst; register void *return_dst __asm__ ("r10") = pdst;
register char *dst __asm__ ("r13") = pdst; register unsigned char *dst __asm__ ("r13") = pdst;
register const char *src __asm__ ("r11") = psrc; register unsigned const char *src __asm__ ("r11") = psrc;
register int n __asm__ ("r12") = pn; register int n __asm__ ("r12") = pn;
/* When src is aligned but not dst, this makes a few extra needless /* 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 cycles. I believe it would take as many to check that the
re-alignment was unnecessary. */ re-alignment was unnecessary. */
...@@ -61,7 +65,7 @@ void *memcpy(void *pdst, ...@@ -61,7 +65,7 @@ void *memcpy(void *pdst,
if ((unsigned long) dst & 1) if ((unsigned long) dst & 1)
{ {
n--; n--;
*(char*)dst = *(char*)src; *dst = *src;
src++; src++;
dst++; dst++;
} }
...@@ -69,151 +73,164 @@ void *memcpy(void *pdst, ...@@ -69,151 +73,164 @@ void *memcpy(void *pdst,
if ((unsigned long) dst & 2) if ((unsigned long) dst & 2)
{ {
n -= 2; n -= 2;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
src += 2; src += 2;
dst += 2; dst += 2;
} }
} }
/* Decide which copying method to use. Movem is dirt cheap, so the /* Decide which copying method to use. */
overheap is low enough to always use the minimum block size as the if (n >= MEMCPY_BY_BLOCK_THRESHOLD)
threshold. */
if (n >= 44)
{ {
/* For large copies we use 'movem' */
/* It is not optimal to tell the compiler about clobbering any /* It is not optimal to tell the compiler about clobbering any
registers; that will move the saving/restoring of those registers registers; that will move the saving/restoring of those registers
to the function prologue/epilogue, and make non-movem sizes to the function prologue/epilogue, and make non-movem sizes
suboptimal. */ suboptimal. */
__asm__ volatile (" \n\ __asm__ volatile
;; Check that the register asm declaration got right. \n\ ("\
;; The GCC manual explicitly says TRT will happen. \n\ ;; 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\ .ifnc %0-%1-%2,$r13-$r11-$r12 \n\
.err \n\ .error \"GCC reg alloc bug: %0-%1-%4 != $r13-$r12-$r11\" \n\
.endif \n\ .endif \n\
\n\ \n\
;; Save the registers we'll use in the movem process \n\ ;; Save the registers we'll use in the movem process \n\
\n\
;; on the stack. \n\ ;; on the stack. \n\
subq 11*4,$sp \n\ subq 11*4,sp \n\
movem $r10,[$sp] \n\ movem r10,[sp] \n\
\n\ \n\
;; Now we've got this: \n\ ;; Now we've got this: \n\
;; r11 - src \n\ ;; r11 - src \n\
;; r13 - dst \n\ ;; r13 - dst \n\
;; r12 - n \n\ ;; r12 - n \n\
\n\ \n\
;; Update n for the first loop \n\ ;; Update n for the first loop. \n\
subq 44,$r12 \n\ subq 44,r12 \n\
0: \n\ 0: \n\
movem [$r11+],$r10 \n\ "
subq 44,$r12 \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\ bge 0b \n\
movem $r10,[$r13+] \n\ movem r10,[r13+] \n\
\n\ \n\
addq 44,$r12 ;; compensate for last loop underflowing n \n\ ;; Compensate for last loop underflowing n. \n\
addq 44,r12 \n\
\n\ \n\
;; Restore registers from stack \n\ ;; Restore registers from stack. \n\
movem [$sp+],$r10" movem [sp+],r10"
/* Outputs */ : "=r" (dst), "=r" (src), "=r" (n) /* Outputs. */
/* Inputs */ : "0" (dst), "1" (src), "2" (n)); : "=r" (dst), "=r" (src), "=r" (n)
/* Inputs. */
: "0" (dst), "1" (src), "2" (n));
} }
/* Either we directly starts copying, using dword copying while (n >= 16)
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)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
n -= 16; n -= 16;
} }
/* A switch() is definitely the fastest although it takes a LOT of code.
* Particularly if you inline code this.
*/
switch (n) switch (n)
{ {
case 0: case 0:
break; break;
case 1: case 1:
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 2: case 2:
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 3: case 3:
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 4: case 4:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src;
break; break;
case 5: case 5:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 6: case 6:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 7: case 7:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 8: case 8:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src;
break; break;
case 9: case 9:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 10: case 10:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 11: case 11:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 12: case 12:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src;
break; break;
case 13: case 13:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
case 14: case 14:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*(short*)dst = *(short*)src; *(short *) dst = *(short *) src;
break; break;
case 15: case 15:
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((long*)dst)++ = *((long*)src)++; *(long *) dst = *(long *) src; dst += 4; src += 4;
*((short*)dst)++ = *((short*)src)++; *(short *) dst = *(short *) src; dst += 2; src += 2;
*(char*)dst = *(char*)src; *dst = *src;
break; break;
} }
return return_dst; /* destination pointer. */ return return_dst;
} /* memcpy() */ }
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7