annotate model/calc.h @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).

/*
    calc.h
    ======

    definitions to make model source portable across calculation type.
    Used fixed point representation for real numbers in integer machines.

    Type names:
	DataType - type used to pass results between modules
		   EG. usually a short.
	StoreType - type used to store an intermediate result within a module
	ScalarType - type used to store fixed-point multipliers

    Integer arithmetic:

	SCALE - convert to fixed point
	SCALAR- float to fixed to fixed point multiplier
		(Used to create a value for a ScalarType).
	DESCALE - convert back to int (opposite of SCALE).

	UNSCALE - convert fixed point back to float.

	Use int instead float to get fixed point arithmetic, but shift
	numbers to preserve the significant digits, EG for multiplication:
		use SCALAR on one operand (which will then be a ScalarType)
		use DESCALE on the result
*/

#if 1                   /* Switch to convert whole model to floating point */
#define FLOAT float     /* version (default uses integer arithmetic)       */
#endif

#ifdef  DSP32
#define FLOAT float
#endif


#ifdef  FLOAT

typedef FLOAT ScalarType ;
typedef FLOAT  StoreType ;
typedef FLOAT   DataType ;

#define   SCALE( _num ) (          _num                         )
#define  SCALAR( _num ) (          _num                         )
#define DESCALE( _num ) (          _num                         )
#define UNSCALE( _num ) (          _num                         )

#else

typedef long ScalarType ;
typedef long  StoreType ;
typedef short  DataType ;

#define   SCALE( _num ) ( (long) ( _num )                << 16l         )
#define  SCALAR( _num ) (        ( _num ) *         ( 1l << 16l ) + 0.5 )
#define DESCALE( _num ) ( (long) ( _num )                >> 16l         )
#define UNSCALE( _num ) (        ( _num ) / (float) ( 1l << 16l )       )

#endif