67 lines
1.2 KiB
C
67 lines
1.2 KiB
C
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/* void _SubUnsArr(src1,src2,n)
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*
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* ARGUMENT
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* unsigned *src1, *src2;
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* int n;
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*
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* DESCRIPTION
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* Subtracts src2 from src1 putting the result in src1. It's assumed
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* that caller has checked to assure that src1>src2 so no borrow can ever
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* be generate (that's why this is a void!!).
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*
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* SIDE EFFECTS
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* The original value of src1 is destroyed.
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*
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* RETURNS
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* None.
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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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void _SubUnsArr(src1, src2, n)
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unsigned SHORT src1[], src2[];
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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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src1[i]=(unsigned SHORT)(psrc-(unsigned long)src2[i]);
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}
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}
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}
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