--- /dev/null
+/*#************************************************************************#*/
+/*#-------------------------------------------------------------------------*/
+/*# */
+/*# FUNCTION NAME: memcpy() */
+/*# */
+/*# PARAMETERS: void* dst; Destination address. */
+/*# void* src; Source address. */
+/*# int len; Number of bytes to copy. */
+/*# */
+/*# RETURNS: dst. */
+/*# */
+/*# DESCRIPTION: Copies len bytes of memory from src to dst. No guarantees */
+/*# about copying of overlapping memory areas. This routine is */
+/*# very sensitive to compiler changes in register allocation. */
+/*# Should really be rewritten to avoid this problem. */
+/*# */
+/*#-------------------------------------------------------------------------*/
+/*# */
+/*# HISTORY */
+/*# */
+/*# DATE NAME CHANGES */
+/*# ---- ---- ------- */
+/*# 941007 Kenny R Creation */
+/*# 941011 Kenny R Lots of optimizations and inlining. */
+/*# 941129 Ulf A Adapted for use in libc. */
+/*# 950216 HP N==0 forgotten if non-aligned src/dst. */
+/*# Added some optimizations. */
+/*# 001025 HP Make src and dst char *. Align dst to */
+/*# dword, not just word-if-both-src-and-dst- */
+/*# are-misaligned. */
+/*# */
+/*#-------------------------------------------------------------------------*/
+
+#include <linux/types.h>
+
+void *memcpy(void *pdst,
+ const void *psrc,
+ size_t pn)
+{
+ /* Ok. 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 char *dst __asm__ ("r13") = pdst;
+ register 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--;
+ *(char*)dst = *(char*)src;
+ src++;
+ dst++;
+ }
+
+ if ((unsigned long) dst & 2)
+ {
+ n -= 2;
+ *(short*)dst = *(short*)src;
+ src += 2;
+ dst += 2;
+ }
+ }
+
+ /* Decide which copying method to use. Movem is dirt cheap, so the
+ overheap is low enough to always use the minimum block size as the
+ threshold. */
+ if (n >= 44)
+ {
+ /* 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. */
+ __asm__ volatile (" \n\
+ ;; Check that the register asm declaration got right. \n\
+ ;; The GCC manual explicitly says TRT will happen. \n\
+ .ifnc %0-%1-%2,$r13-$r11-$r12 \n\
+ .err \n\
+ .endif \n\
+ \n\
+ ;; Save the registers we'll use in the movem process \n\
+ \n\
+ ;; on the stack. \n\
+ subq 11*4,$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,$r12 \n\
+0: \n\
+ movem [$r11+],$r10 \n\
+ subq 44,$r12 \n\
+ bge 0b \n\
+ movem $r10,[$r13+] \n\
+ \n\
+ addq 44,$r12 ;; compensate for last loop underflowing n \n\
+ \n\
+ ;; Restore registers from stack \n\
+ movem [$sp+],$r10"
+
+ /* Outputs */ : "=r" (dst), "=r" (src), "=r" (n)
+ /* Inputs */ : "0" (dst), "1" (src), "2" (n));
+
+ }
+
+ /* 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)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ 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*)src;
+ break;
+ case 2:
+ *(short*)dst = *(short*)src;
+ break;
+ case 3:
+ *((short*)dst)++ = *((short*)src)++;
+ *(char*)dst = *(char*)src;
+ break;
+ case 4:
+ *((long*)dst)++ = *((long*)src)++;
+ break;
+ case 5:
+ *((long*)dst)++ = *((long*)src)++;
+ *(char*)dst = *(char*)src;
+ break;
+ case 6:
+ *((long*)dst)++ = *((long*)src)++;
+ *(short*)dst = *(short*)src;
+ break;
+ case 7:
+ *((long*)dst)++ = *((long*)src)++;
+ *((short*)dst)++ = *((short*)src)++;
+ *(char*)dst = *(char*)src;
+ break;
+ case 8:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ break;
+ case 9:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *(char*)dst = *(char*)src;
+ break;
+ case 10:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *(short*)dst = *(short*)src;
+ break;
+ case 11:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((short*)dst)++ = *((short*)src)++;
+ *(char*)dst = *(char*)src;
+ break;
+ case 12:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ break;
+ case 13:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *(char*)dst = *(char*)src;
+ break;
+ case 14:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *(short*)dst = *(short*)src;
+ break;
+ case 15:
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((long*)dst)++ = *((long*)src)++;
+ *((short*)dst)++ = *((short*)src)++;
+ *(char*)dst = *(char*)src;
+ break;
+ }
+
+ return return_dst; /* destination pointer. */
+} /* memcpy() */
git.openpandora.org / pandora-kernel.git / blobdiff