Source to src/include/fpp-unknown.h

 /*
  * UAE - The Un*x Amiga Emulator
  *
  * MC68881 emulation
  *
  * Conversion routines for hosts with unknown floating point format.
  *
  * Copyright 1996 Herman ten Brugge
  */

#ifndef HAVE_to_single
STATIC_INLINE double to_single (uae_u32 value)
{
    double frac;

    if ((value & 0x7fffffff) == 0)
	return (0.0);
    frac = (double) ((value & 0x7fffff) | 0x800000) / 8388608.0;
    if (value & 0x80000000)
	frac = -frac;
    return (ldexp (frac, ((value >> 23) & 0xff) - 127));
}
#endif

#ifndef HAVE_from_single
STATIC_INLINE uae_u32 from_single (double src)
{
    int expon;
    uae_u32 tmp;
    double frac;

    if (src == 0.0)
	return 0;
    if (src < 0) {
	tmp = 0x80000000;
	src = -src;
    } else {
	tmp = 0;
    }
    frac = frexp (src, &expon);
    frac += 0.5 / 16777216.0;
    if (frac >= 1.0) {
	frac /= 2.0;
	expon++;
    }
    return (tmp | (((expon + 127 - 1) & 0xff) << 23) |
	    (((int) (frac * 16777216.0)) & 0x7fffff));
}
#endif

#ifndef HAVE_to_exten
STATIC_INLINE double to_exten(uae_u32 wrd1, uae_u32 wrd2, uae_u32 wrd3)
{
    double frac;

    if ((wrd1 & 0x7fff0000) == 0 && wrd2 == 0 && wrd3 == 0)
	return 0.0;
    frac = (double) wrd2 / 2147483648.0 +
	(double) wrd3 / 9223372036854775808.0;
    if (wrd1 & 0x80000000)
	frac = -frac;
    return ldexp (frac, ((wrd1 >> 16) & 0x7fff) - 16383);
}
#endif

#ifndef HAVE_from_exten
STATIC_INLINE void from_exten(double src, uae_u32 * wrd1, uae_u32 * wrd2, uae_u32 * wrd3)
{
    int expon;
    double frac;

    if (src == 0.0) {
	*wrd1 = 0;
	*wrd2 = 0;
	*wrd3 = 0;
	return;
    }
    if (src < 0) {
	*wrd1 = 0x80000000;
	src = -src;
    } else {
	*wrd1 = 0;
    }
    frac = frexp (src, &expon);
    frac += 0.5 / 18446744073709551616.0;
    if (frac >= 1.0) {
	frac /= 2.0;
	expon++;
    }
    *wrd1 |= (((expon + 16383 - 1) & 0x7fff) << 16);
    *wrd2 = (uae_u32) (frac * 4294967296.0);
    *wrd3 = (uae_u32) (frac * 18446744073709551616.0 - *wrd2 * 4294967296.0);
}
#endif

#ifndef HAVE_to_double
STATIC_INLINE double to_double(uae_u32 wrd1, uae_u32 wrd2)
{
    double frac;

    if ((wrd1 & 0x7fffffff) == 0 && wrd2 == 0)
	return 0.0;
    frac = (double) ((wrd1 & 0xfffff) | 0x100000) / 1048576.0 +
	(double) wrd2 / 4503599627370496.0;
    if (wrd1 & 0x80000000)
	frac = -frac;
    return ldexp (frac, ((wrd1 >> 20) & 0x7ff) - 1023);
}
#endif

#ifndef HAVE_from_double
STATIC_INLINE void from_double(double src, uae_u32 * wrd1, uae_u32 * wrd2)
{
    int expon;
    int tmp;
    double frac;

    if (src == 0.0) {
	*wrd1 = 0;
	*wrd2 = 0;
	return;
    }
    if (src < 0) {
	*wrd1 = 0x80000000;
	src = -src;
    } else {
	*wrd1 = 0;
    }
    frac = frexp (src, &expon);
    frac += 0.5 / 9007199254740992.0;
    if (frac >= 1.0) {
	frac /= 2.0;
	expon++;
    }
    tmp = (uae_u32) (frac * 2097152.0);
    *wrd1 |= (((expon + 1023 - 1) & 0x7ff) << 20) | (tmp & 0xfffff);
    *wrd2 = (uae_u32) (frac * 9007199254740992.0 - tmp * 4294967296.0);
}
#endif