76 lines
1.2 KiB
C
76 lines
1.2 KiB
C
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/* double ConvDecimalToDouble(x)
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*
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* ARGUMENT
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* DEC *x;
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*
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* DESCRIPTION
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* Converts a DEC to a double. It requires a global variable eTwoTo32,
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* 2^32 in double notation, and ergGMPowersOfTenDouble, an array of
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* powers of ten in double notation.
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*
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* SIDE EFFECTS
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* None.
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*
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* RETURNS
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* The double if the conversion is successful, and the error code
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* otherwise.
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*
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* POSSIBLE ERROR CODES
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*
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* GM_NULLPOINTER
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*
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* AUTHOR
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* Jared Levy Feb. 9, 1987
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* Copyright (C) 1987-1990 Greenleaf Software Inc. All rights reserved.
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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 "gm.h"
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#include "gmsystem.h"
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double ConvDecimalToDouble(x)
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DEC *x;
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{
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int p;
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double f, g;
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_MacStart(GM_DTODF);
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/* check for null pointer */
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_MacInVar(x, 0.0);
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/* change 64-bit number to double */
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f = (double) x->ls.lsl[0];
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if (f<0.0)
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f+= eTwoTo32;
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if (x->ls.lsl[1] != 0) {
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g = (double) x->ls.lsl[1];
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if (g<0.0)
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g+=eTwoTo32;
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f+= (g * eTwoTo32);
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}
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if (x->ls.lmsd != 0)
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f+= ((double) x->ls.lmsd) * eTwoTo64;
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/* adjust by power of 10 */
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p = x->ls.lid;
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while (p>=25) {
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f = f / 1e25;
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p-= 25;
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}
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f = f / ergGMPowersOfTenDouble[p];
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/* make negative numbers negative */
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if (_MacIsDecN(x)) {
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f = -f;
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}
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_MacRet(f);
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}
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