mirror of
https://github.com/adtools/clib2.git
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66303e9ba2
with the library yet. - The byteswap code was contributed by Peter Bengtsson. Thank you very much! git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@15163 87f5fb63-7c3d-0410-a384-fd976d0f7a62
113 lines
2.4 KiB
C
113 lines
2.4 KiB
C
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#if defined(__GNUC__) && defined(__PPC__)
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/* r3=from, r4=to, r5=len, r6=index, r7=load/store temp */
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asm("\
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.text\n\
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.align 2\n\
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.globl swab32\n\
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.type swab32,@function\n\
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swab32:\n\
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srawi. %r5,%r5,2\n\
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li %r6,0\n\
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bc 4,gt,.exit\n\
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mtctr %r5\n\
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.loop:\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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bc 0,lt,.loop\n\
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.exit:\n\
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or %r3,%r4,%r4\n\
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blr\n\
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");
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/* r3=from, r4=to, r5=len/temp, r6=index, r7=load/store temp, r8=cache hint
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*
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* The unrolled, cache-hinting version appears to be about 4.5% faster, but
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* in this case I opted for the smaller implementation. swab64() appears to
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* gain more from cache-hinting - probably because of it using more registers
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* for intermediate storage.
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asm("\
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.text\n\
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.align 2\n\
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.globl swab32\n\
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.type swab32,@function\n\
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swab32:\n\
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dcbt 0,%r3\n\
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andi. %r8,%r5,31 # The number of bytes handled in '.pre'. Used for prefetch hint.\n\
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srawi %r5,%r5,2 # Convert bytes-># of 32-bit words\n\
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andi. %r7,%r5,7\n\
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li %r6,0\n\
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bc 4,gt,.preploop\n\
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mtctr %r7\n\
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.pre: # One 32-bit word at a time until we have (nLeft%8)==0 \n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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bc 0,lt,.pre\n\
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.preploop:\n\
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srawi. %r5,%r5,3 # Divide by 8 again to get number of loops.\n\
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addi %r8,%r8,32 # Start address for next loop (from r3).\n\
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bc 4,gt,.exit\n\
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mtctr %r5\n\
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.loop: # Loop unrolled 8 times = 32 bytes = 1 cache-line (except on the 970).\n\
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dcbt %r8,%r3 # Cache hint (prefetch) for the next loop\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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lwbrx %r7,%r6,%r3\n\
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stwx %r7,%r6,%r4\n\
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addi %r6,%r6,4\n\
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addi %r8,%r8,32 # Update cache-hint offset\n\
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bc 0,lt,.loop\n\
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.exit:\n\
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or %r3,%r4,%r4\n\
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blr\n\
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");
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*/
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#else
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#include <sys/types.h>
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#include <stdint.h>
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void *swab32(void *from,void *to,ssize_t len)
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{
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int i;
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uint32_t *u32in=from,*u32out=to,tmp;
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for(i=0;i<(len>>2);i++) {
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tmp=u32in[i];
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u32out[i]=((tmp&0xff)<<24)|
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((tmp&0xff00)<<8)|
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((tmp&0xff0000)>>8)|
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((tmp&0xff000000)>>24);
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}
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return(to);
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}
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#endif
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