INTERFACE TInt;

This interface provides simulations of the target machine's signed integer 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 Int, IBytes;

CONST
  Zero = Int{NUMBER (IBytes), IBytes{16_00,16_00,..}};
  One  = Int{NUMBER (IBytes), IBytes{16_01,16_00,..}};
  MOne = Int{NUMBER (IBytes), IBytes{16_ff,16_ff,..}};

PROCEDURE FromInt (x: INTEGER;  n: CARDINAL;  VAR i: Int): BOOLEAN;

converts a host integer 'x' to a target integer 'i'

PROCEDURE IntI (READONLY x: Int;  n: CARDINAL;  VAR i: Int): BOOLEAN;

converts a target integer 'x' to a target integer 'i'

PROCEDURE ToInt (READONLY i: Int;  VAR x: INTEGER): BOOLEAN;

converts a target integer 'i' to a host integer 'x'

PROCEDURE New (READONLY chars: ARRAY OF CHAR;  n: CARDINAL;
               VAR i: Int): BOOLEAN;

converts the string of decimal characters in 'chars' to an integer value in 'i'

PROCEDURE Add (READONLY a, b: Int;  VAR i: Int): BOOLEAN;

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

PROCEDURE Subtract (READONLY a, b: Int;  VAR i: Int): BOOLEAN;

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

PROCEDURE Multiply (READONLY a, b: Int;  VAR i: Int): BOOLEAN;

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

PROCEDURE Div (READONLY a, b: Int;  VAR i: Int): BOOLEAN;

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

PROCEDURE Mod (READONLY a, b: Int;  VAR i: Int): BOOLEAN;

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

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

returns 'a = b'

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

returns 'a < b'

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

returns 'a <= b'

PROCEDURE ToChars (READONLY i: Int;  VAR buf: ARRAY OF CHAR): INTEGER;

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

PROCEDURE ToBytes (READONLY i: Int;  VAR buf: ARRAY OF [0..255]): INTEGER;

converts 'i' to the shortest sequence of bytes in little-endian order which when sign-extended equal 'i'. Returns the number of significant bytes in the result. Returns -1 if 'buf' is too short.

END TInt.