-/*#************************************************************************#*/
-/*#-------------------------------------------------------------------------*/
-/*# */
-/*# 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;
+}
git.samba.org / sfrench / cifs-2.6.git / blobdiff