78 lines
1.3 KiB
C
78 lines
1.3 KiB
C
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/* int _SubUnsArrFromUnsArr(src1,src2,dst,n)
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*
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* ARGUMENT
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* unsigned *src1, *src2, *dst;
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* unsigned n;
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*
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* DESCRIPTION
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* Subtracts src2 from src2 giving dst. src1 and src2 are unchanged.
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* src1, src2 and dst point to unsigned arrays.
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*
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* SIDE EFFECTS
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*
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*
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* RETURNS
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* GM_SUCCESS if no overflow, otherwise GM_FAILURE.
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*
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* AUTHOR
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* Brugnoli Giugno 1992
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*
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* MODIFICATIONS
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*
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*/
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#include <stdio.h>
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#include <math.h>
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#include "gm.h"
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#include "gmsystem.h"
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extern double pow(double, double);
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int _SubUnsArrFromUnsArr(src1, src2, dst, n)
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unsigned SHORT src1[], src2[], dst[];
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int n;
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{
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int i;
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unsigned long psrc,maxunsint;
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unsigned SHORT carry;
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carry=0;
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#ifdef SH_LIB
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maxunsint=1;
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for (i=1;i<=BITSPERUI;i++) maxunsint*=2;
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maxunsint--;
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#else
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maxunsint=(unsigned long)pow(2.,(float)BITSPERUI)-1;
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#endif
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if (n>0)
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{
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for (i=0;i<n;i++)
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{
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if (src2[i]>src1[i])
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{
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psrc=maxunsint+0x1L+(long)src1[i]-(long)carry;
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carry=1;
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}
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else
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{
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psrc=src1[i]-carry;
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carry=0;
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}
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dst[i]=(unsigned SHORT)(psrc-(unsigned long)src2[i]);
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}
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if (carry)
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{
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return(GM_FAILURE);
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}
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else
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{
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return(GM_SUCCESS);
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}
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}
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else
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{
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return(GM_SUCCESS);
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}
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}
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