; number.h

; Author:  Douglas W. Jones
; Purpose: Definiton of the abstract class number

; all instances of subclasses of numbers
; begin with a pointer to the class descriptor

; For all methods of all subclasses of this class:
; linkage is always through R1
; unless the method-specific documentation says otherwise,
;   registers 3 to 7 may be destroyed by the call.

; the class descriptors of all subclasses of numbers
; are always structured as follows:

NASSBIN =       0       ; pointer to int assign routine
        ; takes   R3 = pointer to destination number object
        ; takes   R4 = binary integer value to assign
	; returns R3 = pointer to destination object
	;   this routine may have to convert from binary
	;   integer into the required numeric type

NASSNUM =       4       ; pointer to number assign routine
	; takes   R3 = pointer to the destination number object
	; takes   R4 = pointer to the source number object
	; returns R3 = pointer to destination object
	;   this routine may have to convert from one
	;   numeric type into the required numeric type

NTOBIN  =       8       ; pointer to number to binary routine
	; takes   R3 = pointer to the source number object
	; returns R3 = corresponding binary integer value
	;   this routine may have to convert to binary integer

NTODSP  =      12       ; pointer to display number routine
	; takes   R3 = pointer to the source number object
	; returns R3 = pointer to source object
	;   as a side effect, the number is displayed on the
	;   display screen.

NADD    =      16       ; pointer to number add routine
	; takes   R3 = pointer to the destination number object
	; takes   R4 = pointer to the source number object
	; returns R3 = pointer to destination object
	;   add the source object's value to the destination;
	;   if they are the same type, do it the easy way,
	;   otherwise, do the necessary conversion.

NSUB    =      20       ; pointer to number subtract routine
	; takes   R3 = pointer to the destination number object
	; takes   R4 = pointer to the source number object
	; returns R3 = pointer to destination object
	;   subtract the source object from the destination;
	;   if they are the same type, do it the easy way,
	;   otherwise, do the necessary conversion.

NMUL    =      24       ; pointer to number multiply routine
	; takes   R3 = pointer to the destination number object
	; takes   R4 = pointer to the source number object
	; returns R3 = pointer to destination object
	;   multiply the source object by the destination;
	;   if they are the same type, do it the easy way,
	;   otherwise, do the necessary conversion.

NDIV    =      28       ; pointer to number divide routine
	; takes   R3 = pointer to the destination number object
	; takes   R4 = pointer to the source number object
	; returns R3 = pointer to destination object
	;   divide the source object by the destination;
	;   if they are the same type, do it the easy way,
	;   otherwise, do the necessary conversion.