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2e2cd8bad6
Add \n\ at end of lines inside asm statement to avoid warning. No change except adding \n\ to end of line and correcting whitespace has been done. Removes warning about multi-line string literals when compiling arch/cris/arch-v10/lib/memset.c Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Mikael Starvik <mikael.starvik@axis.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
253 lines
8.3 KiB
C
253 lines
8.3 KiB
C
/*#************************************************************************#*/
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/*#-------------------------------------------------------------------------*/
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/*# */
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/*# FUNCTION NAME: memset() */
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/*# */
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/*# PARAMETERS: void* dst; Destination address. */
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/*# int c; Value of byte to write. */
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/*# int len; Number of bytes to write. */
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/*# */
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/*# RETURNS: dst. */
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/*# */
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/*# DESCRIPTION: Sets the memory dst of length len bytes to c, as standard. */
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/*# Framework taken from memcpy. This routine is */
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/*# very sensitive to compiler changes in register allocation. */
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/*# Should really be rewritten to avoid this problem. */
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/*# */
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/*#-------------------------------------------------------------------------*/
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/*# */
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/*# HISTORY */
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/*# */
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/*# DATE NAME CHANGES */
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/*# ---- ---- ------- */
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/*# 990713 HP Tired of watching this function (or */
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/*# really, the nonoptimized generic */
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/*# implementation) take up 90% of simulator */
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/*# output. Measurements needed. */
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/*# */
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/*#-------------------------------------------------------------------------*/
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#include <linux/types.h>
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/* No, there's no macro saying 12*4, since it is "hard" to get it into
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the asm in a good way. Thus better to expose the problem everywhere.
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*/
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/* Assuming 1 cycle per dword written or read (ok, not really true), and
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one per instruction, then 43+3*(n/48-1) <= 24+24*(n/48-1)
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so n >= 45.7; n >= 0.9; we win on the first full 48-byte block to set. */
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#define ZERO_BLOCK_SIZE (1*12*4)
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void *memset(void *pdst,
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int c,
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size_t plen)
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{
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/* Ok. Now we want the parameters put in special registers.
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Make sure the compiler is able to make something useful of this. */
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register char *return_dst __asm__ ("r10") = pdst;
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register int n __asm__ ("r12") = plen;
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register int lc __asm__ ("r11") = c;
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/* Most apps use memset sanely. Only those memsetting about 3..4
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bytes or less get penalized compared to the generic implementation
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- and that's not really sane use. */
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/* Ugh. This is fragile at best. Check with newer GCC releases, if
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they compile cascaded "x |= x << 8" sanely! */
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__asm__("movu.b %0,$r13\n\t"
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"lslq 8,$r13\n\t"
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"move.b %0,$r13\n\t"
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"move.d $r13,%0\n\t"
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"lslq 16,$r13\n\t"
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"or.d $r13,%0"
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: "=r" (lc) : "0" (lc) : "r13");
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{
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register char *dst __asm__ ("r13") = pdst;
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/* This is NONPORTABLE, but since this whole routine is */
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/* grossly nonportable that doesn't matter. */
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if (((unsigned long) pdst & 3) != 0
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/* Oops! n=0 must be a legal call, regardless of alignment. */
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&& n >= 3)
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{
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if ((unsigned long)dst & 1)
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{
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*dst = (char) lc;
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n--;
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dst++;
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}
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if ((unsigned long)dst & 2)
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{
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*(short *)dst = lc;
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n -= 2;
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dst += 2;
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}
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}
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/* Now the fun part. For the threshold value of this, check the equation
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above. */
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/* Decide which copying method to use. */
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if (n >= ZERO_BLOCK_SIZE)
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{
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/* For large copies we use 'movem' */
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/* It is not optimal to tell the compiler about clobbering any
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registers; that will move the saving/restoring of those registers
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to the function prologue/epilogue, and make non-movem sizes
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suboptimal.
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This method is not foolproof; it assumes that the "asm reg"
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declarations at the beginning of the function really are used
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here (beware: they may be moved to temporary registers).
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This way, we do not have to save/move the registers around into
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temporaries; we can safely use them straight away.
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If you want to check that the allocation was right; then
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check the equalities in the first comment. It should say
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"r13=r13, r12=r12, r11=r11" */
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__asm__ volatile ("\n\
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;; Check that the following is true (same register names on \n\
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;; both sides of equal sign, as in r8=r8): \n\
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;; %0=r13, %1=r12, %4=r11 \n\
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;; \n\
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;; Save the registers we'll clobber in the movem process \n\
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;; on the stack. Don't mention them to gcc, it will only be \n\
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;; upset. \n\
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subq 11*4,$sp \n\
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movem $r10,[$sp] \n\
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\n\
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move.d $r11,$r0 \n\
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move.d $r11,$r1 \n\
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move.d $r11,$r2 \n\
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move.d $r11,$r3 \n\
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move.d $r11,$r4 \n\
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move.d $r11,$r5 \n\
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move.d $r11,$r6 \n\
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move.d $r11,$r7 \n\
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move.d $r11,$r8 \n\
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move.d $r11,$r9 \n\
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move.d $r11,$r10 \n\
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\n\
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;; Now we've got this: \n\
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;; r13 - dst \n\
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;; r12 - n \n\
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\n\
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;; Update n for the first loop \n\
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subq 12*4,$r12 \n\
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0: \n\
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subq 12*4,$r12 \n\
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bge 0b \n\
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movem $r11,[$r13+] \n\
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\n\
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addq 12*4,$r12 ;; compensate for last loop underflowing n \n\
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\n\
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;; Restore registers from stack \n\
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movem [$sp+],$r10"
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/* Outputs */ : "=r" (dst), "=r" (n)
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/* Inputs */ : "0" (dst), "1" (n), "r" (lc));
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}
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/* Either we directly starts copying, using dword copying
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in a loop, or we copy as much as possible with 'movem'
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and then the last block (<44 bytes) is copied here.
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This will work since 'movem' will have updated src,dst,n. */
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while ( n >= 16 )
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{
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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n -= 16;
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}
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/* A switch() is definitely the fastest although it takes a LOT of code.
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* Particularly if you inline code this.
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*/
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switch (n)
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{
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case 0:
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break;
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case 1:
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*(char*)dst = (char) lc;
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break;
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case 2:
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*(short*)dst = (short) lc;
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break;
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case 3:
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*((short*)dst)++ = (short) lc;
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*(char*)dst = (char) lc;
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break;
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case 4:
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*((long*)dst)++ = lc;
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break;
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case 5:
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*((long*)dst)++ = lc;
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*(char*)dst = (char) lc;
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break;
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case 6:
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*((long*)dst)++ = lc;
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*(short*)dst = (short) lc;
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break;
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case 7:
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*((long*)dst)++ = lc;
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*((short*)dst)++ = (short) lc;
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*(char*)dst = (char) lc;
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break;
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case 8:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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break;
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case 9:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*(char*)dst = (char) lc;
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break;
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case 10:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*(short*)dst = (short) lc;
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break;
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case 11:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((short*)dst)++ = (short) lc;
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*(char*)dst = (char) lc;
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break;
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case 12:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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break;
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case 13:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*(char*)dst = (char) lc;
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break;
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case 14:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*(short*)dst = (short) lc;
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break;
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case 15:
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((long*)dst)++ = lc;
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*((short*)dst)++ = (short) lc;
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*(char*)dst = (char) lc;
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break;
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}
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}
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return return_dst; /* destination pointer. */
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} /* memset() */
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