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
71 lines
1.4 KiB
C
71 lines
1.4 KiB
C
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#if defined(__GNUC__) && defined(__PPC__)
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/* r3=from, r4=to, r5=len/count, 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 swab\n\
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.type swab,@function\n\
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swab:\n\
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dcbt 0,%r3\n\
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srawi. %r5,%r5,1\n\
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bc 4,gt,.exit\n\
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andi. %r7,%r3,3 # Check if we start on an address evenly divisible by 4.\n\
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li %r6,0\n\
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bc 4,gt,.preploop\n\
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lhbrx %r7,%r6,%r3 # Fix alignment if needed.\n\
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sthx %r7,%r6,%r4\n\
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addi %r6,%r6,2\n\
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subi %r5,%r5,1\n\
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.preploop:\n\
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andi. %r7,%r5,1 # Check if even or odd number of 16-bit words.\n\
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srawi %r5,%r5,1 # Number of 32-bit words to half-swap.\n\
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mtctr %r5\n\
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bc 12,gt,.oddloop # Jump to loop for odd number of 16-bit words.\n\
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.loop: # Loop is 'unrolled' by reading/writing 32-bit words.\n\
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lwbrx %r7,%r6,%r3\n\
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rotlwi %r7,%r7,16\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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.oddloop:\n\
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lwbrx %r7,%r6,%r3\n\
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rotlwi %r7,%r7,16\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,.oddloop\n\
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sub %r6,%r6,2\n\
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lhbrx %r7,%r6,%r3 # Fix last 16-bit word.\n\
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sthx %r7,%r6,%r4\n\
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or %r3,%r4,%r4\n\
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blr\n\
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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 *swab(void *from,void *to,ssize_t len)
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{
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int i;
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uint16_t u16,*u16in=from,*u16out=to;
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for(i=0;i<(len>>1);i++) {
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u16=u16in[i];
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u16out[i]=u16>>8|u16<<8;
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}
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return(u16out);
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}
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#endif
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