0931a7a6d6
- Renamed all pandora-specific folder names to the common WinUAE pattern - Updated the VS Solution to reflect these changes - Updated Makefile to reflect these changes
131 lines
2.9 KiB
C
131 lines
2.9 KiB
C
/*
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* UAE - The Un*x Amiga Emulator
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*
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* MC68881 emulation
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* Support functions for IEEE 754-compatible host CPUs.
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* These functions use a GCC extension (type punning through unions) and
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* should only be compiled with compilers that support this.
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*
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* Copyright 1999 Sam Jordan
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* Copyright 2007 Richard Drummond
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*/
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#define FPCR_ROUNDING_MODE 0x00000030
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#define FPCR_ROUND_NEAR 0x00000000
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#define FPCR_ROUND_ZERO 0x00000010
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#define FPCR_ROUND_MINF 0x00000020
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#define FPCR_ROUND_PINF 0x00000030
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#define FPCR_ROUNDING_PRECISION 0x000000c0
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#define FPCR_PRECISION_SINGLE 0x00000040
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#define FPCR_PRECISION_DOUBLE 0x00000080
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#define FPCR_PRECISION_EXTENDED 0x00000000
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STATIC_INLINE void exten_zeronormalize(uae_u32 *pwrd1, uae_u32 *pwrd2, uae_u32 *pwrd3)
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{
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uae_u32 wrd1 = *pwrd1;
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uae_u32 wrd2 = *pwrd2;
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uae_u32 wrd3 = *pwrd3;
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int exp = (wrd1 >> 16) & 0x7fff;
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// Force zero if mantissa is zero but exponent is non-zero
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// M68k FPU automatically convert them to plain zeros.
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// x86 FPU considers them invalid values
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if (exp != 0 && exp != 0x7fff && !wrd2 && !wrd3) {
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*pwrd1 = (wrd1 & 0x80000000);
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}
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}
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STATIC_INLINE double to_single (uae_u32 value)
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{
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union {
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float f;
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uae_u32 u;
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} val;
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val.u = value;
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return val.f;
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}
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STATIC_INLINE uae_u32 from_single (double src)
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{
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union {
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float f;
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uae_u32 u;
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} val;
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val.f = (float) src;
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return val.u;
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}
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STATIC_INLINE double to_double (uae_u32 wrd1, uae_u32 wrd2)
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{
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union {
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double d;
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uae_u32 u[2];
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} val;
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val.u[0] = wrd2; // little endian
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val.u[1] = wrd1;
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return val.d;
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}
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STATIC_INLINE void from_double (double src, uae_u32 * wrd1, uae_u32 * wrd2)
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{
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uae_u32 *longarray = (uae_u32 *)&src;
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*wrd1 = longarray[1]; // little endian
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*wrd2 = longarray[0];
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}
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static const double twoto32 = 4294967296.0;
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STATIC_INLINE void to_exten(fpdata *fpd, uae_u32 wrd1, uae_u32 wrd2, uae_u32 wrd3)
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{
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double frac;
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exten_zeronormalize(&wrd1, &wrd2, &wrd3);
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if ((wrd1 & 0x7fff0000) == 0 && wrd2 == 0 && wrd3 == 0) {
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fpd->fp = (wrd1 & 0x80000000) ? -0.0 : +0.0;
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return;
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}
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frac = ((double)wrd2 + ((double)wrd3 / twoto32)) / 2147483648.0;
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if (wrd1 & 0x80000000)
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frac = -frac;
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fpd->fp = ldexp (frac, ((wrd1 >> 16) & 0x7fff) - 16383);
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}
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STATIC_INLINE void from_exten(fpdata *fpd, uae_u32 * wrd1, uae_u32 * wrd2, uae_u32 * wrd3)
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{
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int expon;
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double frac;
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fptype v;
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v = fpd->fp;
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if (v == 0.0) {
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*wrd1 = signbit(v) ? 0x80000000 : 0;
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*wrd2 = 0;
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*wrd3 = 0;
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return;
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}
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if (v < 0) {
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*wrd1 = 0x80000000;
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v = -v;
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} else {
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*wrd1 = 0;
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}
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frac = frexp (v, &expon);
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frac += 0.5 / (twoto32 * twoto32);
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if (frac >= 1.0) {
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frac /= 2.0;
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expon++;
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}
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*wrd1 |= (((expon + 16383 - 1) & 0x7fff) << 16);
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*wrd2 = (uae_u32) (frac * twoto32);
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*wrd3 = (uae_u32) ((frac * twoto32 - *wrd2) * twoto32);
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}
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#define HAVE_from_double
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#define HAVE_to_double
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#define HAVE_from_exten
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#define HAVE_to_exten
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#define HAVE_from_single
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#define HAVE_to_single
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