source: buchla-68k/orig/LATTICE/VALUES.H@ 6d3de83

/*
   =============================================================================
        values.h -- values for arithmetic functions
        Version 7 -- 1987-12-16 -- D.N. Lynx Crowe
   =============================================================================
*/

#ifndef BITSPERBYTE

#define gcos    0
#define m68k    1
#define pdp11   0
#define u3b     0
#define u3b5    0
#define u370    0
#define vax     0

/* These values work with any binary representation of integers
 * where the high-order bit contains the sign. */

/* a number used normally for size of a shift */

#if gcos
#define BITSPERBYTE     9
#else
#define BITSPERBYTE     8
#endif

#define BITS(type)      (BITSPERBYTE * (int)sizeof(type))

/* short, regular and long ints with only the high-order bit turned on */

#define HIBITS  ((short)(1 << BITS(short) - 1))
#define HIBITI  (1 << BITS(int) - 1)
#define HIBITL  (1L << BITS(long) - 1)

/* largest short, regular and long int */

#define MAXSHORT        ((short)~HIBITS)
#define MAXINT  (~HIBITI)
#define MAXLONG (~HIBITL)

/* various values that describe the binary floating-point representation

 * _EXPBASE     - the exponent base
 * DMAXEXP      - the maximum exponent of a double (as returned by frexp())
 * FMAXEXP      - the maximum exponent of a float  (as returned by frexp())
 * DMINEXP      - the minimum exponent of a double (as returned by frexp())
 * FMINEXP      - the minimum exponent of a float  (as returned by frexp())
 * MAXDOUBLE    - the largest double
                        ((_EXPBASE ** DMAXEXP) * (1 - (_EXPBASE ** -DSIGNIF)))
 * MAXFLOAT     - the largest float
                        ((_EXPBASE ** FMAXEXP) * (1 - (_EXPBASE ** -FSIGNIF)))
 * MINDOUBLE    - the smallest double (_EXPBASE ** (DMINEXP - 1))
 * MINFLOAT     - the smallest float (_EXPBASE ** (FMINEXP - 1))
 * DSIGNIF      - the number of significant bits in a double
 * FSIGNIF      - the number of significant bits in a float
 * DMAXPOWTWO   - the largest power of two exactly representable as a double
 * FMAXPOWTWO   - the largest power of two exactly representable as a float
 * _IEEE        - 1 if IEEE standard representation is used
 * _DEXPLEN     - the number of bits for the exponent of a double
 * _FEXPLEN     - the number of bits for the exponent of a float
 * _HIDDENBIT   - 1 if high-significance bit of mantissa is implicit
 * LN_MAXDOUBLE - the natural log of the largest double  -- log(MAXDOUBLE)
 * LN_MINDOUBLE - the natural log of the smallest double -- log(MINDOUBLE)
 */

#if u3b || u3b5 || m68k
#define MAXDOUBLE       1.79769313486231470e+308
#define MAXFLOAT        ((float)3.40282346638528860e+38)
#define MINDOUBLE       4.94065645841246544e-324
#define MINFLOAT        ((float)1.40129846432481707e-45)
#define _IEEE           1
#define _DEXPLEN        11
#define _HIDDENBIT      1
#define DMINEXP (-(DMAXEXP + DSIGNIF - _HIDDENBIT - 3))
#define FMINEXP (-(FMAXEXP + FSIGNIF - _HIDDENBIT - 3))
#endif

#if pdp11 || vax
#define MAXDOUBLE       1.701411834604692293e+38
#define MAXFLOAT        ((float)1.701411733192644299e+38)

/* The following is kludged because the PDP-11 compilers botch the simple form.
   The kludge causes the constant to be computed at run-time on the PDP-11,
   even though it is still "folded" at compile-time on the VAX. */

#define MINDOUBLE       (0.01 * 2.938735877055718770e-37)
#define MINFLOAT        ((float)MINDOUBLE)
#define _IEEE           0
#define _DEXPLEN        8
#define _HIDDENBIT      1
#define DMINEXP (-DMAXEXP)
#define FMINEXP (-FMAXEXP)
#endif

#if gcos
#define MAXDOUBLE       1.7014118346046923171e+38
#define MAXFLOAT        ((float)1.7014118219281863150e+38)
#define MINDOUBLE       2.9387358770557187699e-39
#define MINFLOAT        ((float)MINDOUBLE)
#define _IEEE           0
#define _DEXPLEN        8
#define _HIDDENBIT      0
#define DMINEXP (-(DMAXEXP + 1))
#define FMINEXP (-(FMAXEXP + 1))
#endif

#if u370
#define _LENBASE        4
#else
#define _LENBASE        1
#endif

#define _EXPBASE        (1 << _LENBASE)
#define _FEXPLEN        8
#define DSIGNIF (BITS(double) - _DEXPLEN + _HIDDENBIT - 1)
#define FSIGNIF (BITS(float)  - _FEXPLEN + _HIDDENBIT - 1)
#define DMAXPOWTWO      ((double)(1L<<BITS(long)-2)*(1L<<DSIGNIF-BITS(long)+1))
#define FMAXPOWTWO      ((float)(1L << FSIGNIF - 1))
#define DMAXEXP ((1 << _DEXPLEN - 1) - 1 + _IEEE)
#define FMAXEXP ((1 << _FEXPLEN - 1) - 1 + _IEEE)
#define LN_MAXDOUBLE    (M_LN2 * DMAXEXP)
#define LN_MINDOUBLE    (M_LN2 * (DMINEXP - 1))
#define H_PREC  (DSIGNIF % 2 ? (1L << DSIGNIF/2) * M_SQRT2 : 1L << DSIGNIF/2)
#define X_EPS   (1.0/H_PREC)
#define X_PLOSS ((double)(long)(M_PI * H_PREC))
#define X_TLOSS (M_PI * DMAXPOWTWO)
#define M_LN2   0.69314718055994530942
#define M_PI    3.14159265358979323846
#define M_SQRT2 1.41421356237309504880
#define MAXBEXP DMAXEXP /* for backward compatibility */
#define MINBEXP DMINEXP /* for backward compatibility */
#define MAXPOWTWO       DMAXPOWTWO /* for backward compatibility */

#endif