__64tof.h File Reference

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Classes
union	_FLOAT_RESULT

Macros
#define	FRACTION_LEN   23
#define	EXPONENT_LEN   8
#define	SHIFT_OFFSET   (EXPONENT_LEN + 32)
#define	SIGN_MASK   0x8000000000000000ULL
#define	EXPONENT_ZERO   ((1 << (EXPONENT_LEN - 1)) - 1)
#define	NEGATE(x)   (~(x) + 1)

Typedefs
typedef float	FLOAT_TYPE
typedef unsigned int	FINT_TYPE
typedef unsigned long long	INT64SU
typedef union _FLOAT_RESULT	FLOAT_RESULT

Functions
FLOAT_TYPE	__64tof (INT64SU value)

Macro Definition Documentation

EXPONENT_LEN

#define EXPONENT_LEN   8

Definition at line 18 of file __64tof.h.

EXPONENT_ZERO

#define EXPONENT_ZERO   ((1 << (EXPONENT_LEN - 1)) - 1)

Definition at line 36 of file __64tof.h.

FRACTION_LEN

#define FRACTION_LEN   23

Definition at line 17 of file __64tof.h.

NEGATE

#define NEGATE

(

x

)

(~(x) + 1)

Definition at line 38 of file __64tof.h.

SHIFT_OFFSET

#define SHIFT_OFFSET   (EXPONENT_LEN + 32)

Definition at line 19 of file __64tof.h.

SIGN_MASK

#define SIGN_MASK   0x8000000000000000ULL

Definition at line 34 of file __64tof.h.

Typedef Documentation

FINT_TYPE

typedef unsigned int FINT_TYPE

Definition at line 16 of file __64tof.h.

FLOAT_RESULT

typedef union _FLOAT_RESULT FLOAT_RESULT

FLOAT_TYPE

typedef float FLOAT_TYPE

Definition at line 15 of file __64tof.h.

INT64SU

typedef unsigned long long INT64SU

Definition at line 25 of file __64tof.h.

Function Documentation

__64tof()

FLOAT_TYPE __64tof

(

INT64SU

value

)

Definition at line 41 of file __64tof.h.

{
    FLOAT_RESULT result;
    FINT_TYPE exponent = EXPONENT_ZERO + FRACTION_LEN;
    int count = 0;
    unsigned long long mask = SIGN_MASK;
 
    if (value == 0)
        return (FLOAT_TYPE)0;
 
#ifdef _USE_SIGNED_
    if (value & SIGN_MASK)
    {
        value = NEGATE(value);
        /* set Sign bit using exponent */
        exponent |= 1 << EXPONENT_LEN;
    }
#endif
 
    for (; count < 64; count++)
    {
        if (value & mask)
            break;
        mask = mask >> 1;
    }
 
    count -= SHIFT_OFFSET;
    /* exponent is FRACTION_LEN - count */
    exponent -= count;
    result.raw = exponent << FRACTION_LEN;
 
    mask--;
    value = value & mask;
    if (value == 0)
        return result.value;
 
    if (count == 0)
    {
        result.raw |= value;
    }
    else if (count < 0)
    {
        count = NEGATE(count) - 1;
        value = value >> count;
        mask = value & 1;
        result.raw |= value >> 1;
 
        /* round up if left most bit of lost data is 1 */
        if (mask)
            result.raw++;
    }
    else
    {
        result.raw |= value << count;
    }
 
    return result.value;
}