INTERFACE TWord;

This interface provides simulations of unsigned integer operations, at the maximum precision supported by any target.

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;

CONST Size = BITSIZE(Int);

CONST
  Max8  = Int{16_FF, 0, ..};
  Max16 = Int{16_FF, 16_FF, 0, ..};
  Max32 = Int{16_FF, 16_FF, 16_FF, 16_FF, 0, ..};
  Max64 = Int{16_FF, 16_FF, 16_FF, 16_FF, 16_FF, 16_FF, 16_FF, 16_FF};

PROCEDURE New (READONLY chars: ARRAY OF CHAR;  base: [2..16];
               VAR i: Int): BOOLEAN;

converts the string of characters in 'chars' representing a base 'base' number to an integer value in 'i'

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

returns 'Word.Plus (a, b)'

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

returns 'Word.Minus (a, b)'

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

returns 'Word.Times (a, b)'

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

returns 'Word.Divide (a, b)' unless b is zero.

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

returns 'Word.Mod (a, b)' unless b is zero.

PROCEDURE DivMod (READONLY x, y: Int;  VAR q, r: Int);

returns 'q = x DIV y', and 'r = x MOD y', but assumes that 'y # 0'

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

returns 'Word.LT (a, b)'

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

returns 'Word.GT (a, b)'

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

returns 'Word.LE (a, b)'

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

returns 'Word.GE (a, b)'

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

returns 'Word.And (a, b)'

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

returns 'Word.Or (a, b)'

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

returns 'Word.Xor (a, b)'

PROCEDURE Not (READONLY a: Int;  VAR i: Int);

returns 'Word.Not (a)'

PROCEDURE Shift (READONLY a: Int;  b: INTEGER;  VAR r: Int);

returns 'Word.Shift (a, b)'

PROCEDURE LeftShift (READONLY a: Int;  b: [0..Size-1];  VAR r: Int);

returns 'Word.LeftShift (a, b)'

PROCEDURE RightShift (READONLY a: Int;  b: [0..Size-1];  VAR r: Int);

returns 'Word.RightShift (a, b)'

PROCEDURE Rotate (READONLY a: Int;  b: INTEGER;  n: CARDINAL;  VAR r: Int);

returns 'Word.Rotate (a, b)'

PROCEDURE Extract (READONLY a: Int;  b, c: CARDINAL;  VAR r: Int): BOOLEAN;

returns 'Word.Extract (a, b, c)'

PROCEDURE Insert (READONLY a, b: Int;  c, d: CARDINAL;  VAR r: Int): BOOLEAN;

returns 'Word.Insert (a, b, c, d)'

PROCEDURE Truncate (READONLY a: Int;  n: CARDINAL;  VAR r: Int): BOOLEAN;

truncates to the low-order 'n' bytes of 'i'. Returns TRUE if 'i' has at most 'n' significant bytes, FALSE otherwise.

END TWord.