38 lines
759 B
C
38 lines
759 B
C
/** @file z80/support.c
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*/
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#include "z80.h"
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#include <math.h>
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int
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convertFloat (Z80_FLOAT * f, double native)
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{
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unsigned long mantissa, exponent;
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double f2;
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wassert (f);
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if (native != 0)
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{
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f2 = floor (log (fabs (native)) / log (2)) + 1;
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mantissa = (unsigned long) (0x1000000 * fabs (native) / exp (f2 * log (2))) ;
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mantissa &= 0xffffff;
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exponent = (unsigned long) (f2 + 0x40) ;
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if (native < 0)
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exponent |= 0x80;
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}
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else
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{
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mantissa = 0;
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exponent = 0;
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}
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f->w[0] = (WORD) mantissa;
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f->w[1] = (BYTE) (mantissa >> 16);
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f->w[1] |= exponent << 8;
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f->b[0] = (BYTE) f->w[0];
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f->b[1] = (BYTE) (f->w[0] >> 8);
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f->b[2] = (BYTE) f->w[1];
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f->b[3] = (BYTE) (f->w[1] >> 8);
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return 0;
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}
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