INTERFACE TFloat;

This interface provides simulations of the target machine's floating-point operations.

Unless otherwise specified, the arithmetic operations defined below return TRUE if they succeed in producing a new target value, otherwise they return FALSE.

FROM Target IMPORT Float, Precision;

CONST
  ZeroR = Float { Precision.Short,    0, 0.0x0 };
  ZeroL = Float { Precision.Long,     0, 0.0x0 };
  ZeroX = Float { Precision.Extended, 0, 0.0x0 };

PROCEDURE New (READONLY chars: ARRAY OF CHAR;  pre: Precision;
                                                      VAR f: Float): BOOLEAN;

converts 'chars' to a floating point value with the specified precision. Note: regardless of the precision, the exponent must be started by the character 'e'.

PROCEDURE Prec (READONLY f: Float): Precision;

returns the precision of 'f'

PROCEDURE Add (READONLY a, b: Float;  VAR f: Float): BOOLEAN;

returns 'a + b' unless there's an overflow

PROCEDURE Subtract (READONLY a, b: Float;  VAR f: Float): BOOLEAN;

returns 'a - b' unless there's an overflow

PROCEDURE Multiply (READONLY a, b: Float;  VAR f: Float): BOOLEAN;

returns 'a * b' unless there's an overflow

PROCEDURE Divide (READONLY a, b: Float;  VAR f: Float): BOOLEAN;

returns 'a / b' unless there's an overflow

PROCEDURE Mod (READONLY a, b: Float;  VAR f: Float): BOOLEAN;

returns 'a MOD b' unless there's an overflow

PROCEDURE EQ (READONLY a, b: Float): BOOLEAN;

returns 'a = b'

PROCEDURE LT (READONLY a, b: Float): BOOLEAN;

returns 'a < b' unless there's an overflow

PROCEDURE LE (READONLY a, b: Float): BOOLEAN;

returns 'a <= b' unless there's an overflow

PROCEDURE FloatF (READONLY a: Float;  p: Precision;  VAR f: Float): BOOLEAN;

returns 'FLOAT (a, p)' unless there's an overflow

PROCEDURE FloatI (READONLY i: INTEGER;  p: Precision;  VAR f: Float): BOOLEAN;

returns 'FLOAT (i, p)' unless there's an overflow

PROCEDURE Trunc (READONLY a: Float): INTEGER;

returns 'TRUNC(a)'

PROCEDURE Round (READONLY a: Float): INTEGER;

returns 'ROUND(a)'

PROCEDURE Floor (READONLY a: Float): INTEGER;

returns 'FLOOR(a)' unless there's an overflow

PROCEDURE Ceiling (READONLY a: Float): INTEGER;

returns 'CEILING(a)'

PROCEDURE ToChars (READONLY f: Float;  VAR buf: ARRAY OF CHAR): INTEGER;

converts 'f' to a printable string in 'buf'. Returns the number of characters in the string. Returns -1 if 'buf' is too short.

TYPE Byte = [0..255];

PROCEDURE ToBytes (READONLY f: Float;  VAR buf: ARRAY OF Byte): INTEGER;

converts 'f' to an array of bytes in 'buf'. Returns the number of bytes in 'buf'. Returns -1 if 'buf' is too short.

PROCEDURE FromBytes (READONLY buf: ARRAY OF Byte; p: Precision; VAR f: Float);

converts the array of bytes in 'buf' to a float 'f' with precision 'p'.

END TFloat.