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
92 lines
1.6 KiB
C
92 lines
1.6 KiB
C
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#if defined(__GNUC__) && defined(__PPC__)
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/* r3=from, r4=to, r5=len/remaining, r6/r7=index & r7=temp, r8/r9/r10=read/write temp */
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asm("\
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.text\n\
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.align 2\n\
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.globl swab24\n\
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.type swab24,@function\n\
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swab24:\n\
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dcbt 0,%r3\n\
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li %r7,3\n\
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divwu %r5,%r5,%r7\n\
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andi. %r7,%r5,3\n\
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srawi. %r5,%r5,2\n\
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mtctr %r5\n\
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or %r5,%r7,%r7\n\
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li %r6,0\n\
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bc 4,gt,.postfix\n\
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.loop:\n\
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lwbrx %r8,%r6,%r3\n\
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addi %r7,%r6,4\n\
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lwzx %r9,%r7,%r3\n\
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addi %r7,%r6,8\n\
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lwbrx %r10,%r7,%r3\n\
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rotlwi %r8,%r8,8\n\
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or %r7,%r9,%r9\n\
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rlwimi %r9,%r8,16,8,15\n\
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rlwimi %r9,%r10,8,16,23\n\
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rlwimi %r8,%r7,16,24,31\n\
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rotrwi %r10,%r10,8\n\
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rlwimi %r10,%r7,16,0,7\n\
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stwx %r8,%r6,%r4\n\
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addi %r6,%r6,4\n\
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stwx %r9,%r6,%r4\n\
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addi %r6,%r6,4\n\
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stwx %r10,%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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.postfix: # Fix any remaining 24-bit words (number of remaining words in r5).\n\
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or. %r5,%r5,%r5\n\
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bc 4,gt,.exit\n\
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mtctr %r5\n\
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add %r3,%r3,%r6\n\
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add %r6,%r4,%r6\n\
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subi %r3,%r3,1\n\
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.fixloop:\n\
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lbzu %r7,1(%r3)\n\
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lbzu %r8,1(%r3)\n\
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lbzu %r9,1(%r3)\n\
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stb %r7,2(%r6)\n\
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stb %r8,1(%r6)\n\
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stb %r9,0(%r6)\n\
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addi %r6,%r6,3\n\
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bc 0,lt,.fixloop\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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#else
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#include <sys/types.h>
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#include <stdint.h>
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/*
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* Ugh, this is really very, very ineffiecient.
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* (But simple, understandable and safe)
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*/
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void *swab24(void *from,void *to,ssize_t len)
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{
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uint8_t *src=from,B0,B1,B2,*dst=to;
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int i;
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for(i=0;i<len;i+=3) {
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B0=src[i];
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B1=src[i+1];
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B2=src[i+2];
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dst[i]=B2;
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dst[i+1]=B1;
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dst[i+2]=B0;
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}
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return(to);
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}
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#endif
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