(* Release 3.02 *)
(*===========================================================
== JPI-TopSpeed Assembler                                  ==
== Demo assembler skeleton (For Modula-2 and Pascal usage) ==
==                                                         ==
== Module name is ADemo,                                   ==
== all occurances of ADemo should be be replaced           ==
== with your module name                                   ==
==                                                         ==
== The following compiler directives are used extensively  ==
== in this example to show how to create memory model/     ==
== calling convention independent code                     ==
==                                                         ==
==  NearCall     TRUE for memory models small and compact  ==
==  NearPtr      TRUE for memory models small and medium   ==
==  SameDS       TRUE for memory models small, medium,     ==
==                    compact and large                    ==
==  RegParam     TRUE for the JPI calling convention       ==
==  (see corelib.inc for other directives)                 ==
==                                                         ==
==  The compiler directive 'Modula' is also used in this   ==
==  example to show the differences between C and Modula   ==
==  Normally you would decide on the main interface        ==
==  language then create an interface file for the other   ==
==  languages that sets the appropriate pragmas to do      ==
==  the language specific conversions for you              ==
=============================================================*)

include "corelib.inc"

module ADemo

Modula   = 1     (* Set this to 0 to compile as a C style caller *)
InitCode = 1     (* Set this to 0 if no initcode needed e.g. if pragma
                  * (*# module(init_code=>off) *) is in definition file
                  *)


segment _BSS(BSS,28H)

(* Data Goes here *)
public ADemo@GlobalVariable:  org 2

segment _CONST(DATA,28H)

(* Initialized constants go here,
   (Unless const-in-code required (large models only)) *)

(*%T InitCode*)
public ADemo$:                    (* Dependancy list *)

(*%F NearCall*)                   (* Far calls *)
    dd $AnInit                    (* initialization label goes here (far) *)
(*%E NearCall FALSE *)
(*%T NearCall*)                   (* Near Calls *)
  dw $AnInit
                                  (* See pg 108 of the Advanced Developer's *)
                                  (* Guide if you need to initialise other  *)
                                  (* modules                                *)
(*%E NearCall TRUE  *)
    dw -1                         (* Terminates list *)
(*%E InitCode TRUE  *)

(*************************************************************************)
(* This is the initialisation code.  It is equivalent to:                *)
(*                                                                       *)
(* BEGIN                                                                 *)
(*   GlobalVariable := 3;                                                *)
(* END ADemo.                                                            *)
(*                                                                       *)
(*************************************************************************)
(*%F NearCall *)
segment ADemo_TEXT(CODE,28H)
(*%E NearCall FALSE *)
(*%T NearCall *)
segment _TEXT(CODE,28H)
(*%E NearCall TRUE  *)

extrn ADemo@GlobalVariable
public $AnInit:
(*%F SameDS *)
    push ds
    mov  ax, _BSS
    mov  ds, ax
(*%E SameDS FALSE *)
    mov  word [ADemo@GlobalVariable],3
(*%F SameDS *)
    pop  ds
(*%E SameDS FALSE *)
(*%F NearCall *)
    ret  far 0
(*%E NearCall FALSE *)
(*%T NearCall *)
    ret      0
(*%E NearCall TRUE  *)


(*************************************************************************
* respecifying the segment allows the smart linking facility to
* only include the code that is actually used
*
*PROCEDURE AFunc (AString : Str30) : INTEGER;
*VAR
*  A : char;
*
*BEGIN
*  A := AString[0];
*  RETURN (GlobalVariable);
*END AFunc;
**************************************************************************)
(*%F NearCall *)
segment ADemo_TEXT(CODE,28H)
(*%E NearCall FALSE *)
(*%T NearCall *)
segment _TEXT(CODE,28H)
(*%E NearCall TRUE  *)

public ADemo$AFunc:
                    (* (JPI calling convention)
                       Parameters come in the following registers:
                       AX,BX,CX,DX and then on the stack.
                       The following registers should be saved if corrupted
                       BP,DS,SI,DI,ST0,ST1,
                       Also AX,BX,CX and DX (if NOT used as parameters)
                    *)
       push bp
       mov  bp,sp
(*%F RegParam*)
                            (* Move the parameters into the same   *)
                            (* registers as passed by JPI calling  *)
                            (* convention                          *)
(*%F NearPtr *)
       mov   bx,[bp][8]
(*%E NearPtr FALSE *)
       mov   ax,[bp][6]
(*%E RegParam FALSE *)
(*%F NearPtr *)
       sub   sp,6                 (* This is the scratch space for the *)
                                  (* local varaibles.                  *)
       mov   [bp][-4],ax
       mov   [bp][-2],bx
       les   bx,[bp][-4]
       mov   al,es:[bx][1]
       sub   ah,ah
       mov   [bp][-6],al
(*%E NearPtr FALSE *)
(*%T NearPtr *)
       dec   sp
       dec   sp
       mov   bx,ax
(*%F Modula *)
       mov   al,[bx]
(*%E Modula FALSE *)
(*%T Modula *)
       mov   al,[bx][1]
(*%E Modula TRUE  *)
       sub   ah,ah
       mov   [bp][-2],al
(*%E NearPtr TRUE  *)
(*%F SameDS *)
       push ds
       mov  ax, _BSS
       mov  ds, ax              (* Now DS points to the data segment   *)
                                (* containing ADemo@GlobalVariable     *)
(*%E SameDS FALSE *)
       mov   ax,[ADemo@GlobalVariable]
(*%F SameDS *)
       pop ds
(*%E SameDS FALSE *)
       mov   sp,bp
       pop   bp
(*%F RegParam *)
(*%F NearCall *)
(*%F NearPtr *)
       ret   far 4
(*%E NearPtr  FALSE *)
(*%T NearPtr *)
       ret   far 2
(*%E NearPtr  TRUE  *)
(*%E NearCall FALSE *)
(*%T NearCall *)
(*%F NearPtr *)
       ret       4
(*%E NearPtr  FALSE *)
(*%T NearPtr *)
       ret       2
(*%E NearPtr  TRUE  *)
(*%E NearCall TRUE  *)
(*%E RegParam FALSE *)
(*%F NearCall *)
       ret   far 0
(*%E NearCall FALSE *)
(*%T NearCall *)
       ret       0
(*%E NearCall TRUE  *)


(*************************************************************************
*PROCEDURE AProc (VAR variable : CHAR; param : INTEGER);
*BEGIN
*  variable := 'c';
*  GlobalVariable := param;
*END AProc;
**************************************************************************)
(*%F NearCall *)
segment ADemo_TEXT(CODE,28H)
(*%E NearCall FALSE *)
(*%T NearCall *)
segment _TEXT(CODE,28H)
(*%E NearCall TRUE  *)

public ADemo$AProc:
(*%F RegParam*)
                            (* Only need to deal with the stack if *)
                            (* using the stack calling convention  *)
                            (* Note that this is not true for all  *)
                            (* functions.  See AFunc               *)
       push  bp
       mov   bp, sp
                            (* Move the parameters into the same   *)
                            (* registers as passed by JPI calling  *)
                            (* convention                          *)
(*%F Modula *)
(*%F NearPtr *)
       mov   ax,[bp][6]
       mov   bx,[bp][8]
       mov   cx,[bp][10]
(*%E NearPtr FALSE *)
(*%T NearPtr *)
       mov   ax,[bp][6]
       mov   bx,[bp][8]
(*%E NearPtr TRUE *)
(*%E Modula FALSE *)
(*%T Modula *)
(*%F NearPtr *)
       mov   cx,[bp][6]
       mov   ax,[bp][8]
       mov   bx,[bp][10]
(*%E NearPtr FALSE *)
(*%T NearPtr *)
       mov   bx,[bp][6]
       mov   ax,[bp][8]
(*%E NearPtr TRUE *)
(*%E Modula TRUE  *)
(*%E RegParam FALSE*)
       push  si
       mov   si,ax
(*%F NearPtr *)
       mov   es,bx
       mov   byte es:[si],63H
(*%E NearPtr FALSE *)
(*%T NearPtr *)
       mov   byte [si],63H
(*%E NearPtr TRUE  *)
       pop   si
(*%F SameDS *)
       mov   ax, _BSS
       mov   es,ax
       mov   es:[ADemo@GlobalVariable],cx
(*%E SameDS FALSE *)
(*%T SameDS *)
(*%F NearPtr *)
       mov   [ADemo@GlobalVariable],cx
(*%E NearPtr FALSE *)
(*%T NearPtr *)
       mov   [ADemo@GlobalVariable],bx
(*%E NearPtr TRUE  *)
(*%E SameDS TRUE  *)
                            (* Now clean up everything before returning *)
(*%F RegParam *)
       pop bp
(*%F NearCall *)
(*%F NearPtr *)
       ret   far 6
(*%E NearPtr  FALSE *)
(*%T NearPtr *)
       ret   far 4
(*%E NearPtr  TRUE  *)
(*%E NearCall FALSE *)
(*%T NearCall *)
(*%F NearPtr *)
       ret       6
(*%E NearPtr  FALSE *)
(*%T NearPtr *)
       ret       4
(*%E NearPtr  TRUE  *)
(*%E NearCall TRUE  *)
(*%E RegParam FALSE *)
(*%F NearCall *)
       ret   far 0
(*%E NearCall FALSE *)
(*%T NearCall *)
       ret       0
(*%E NearCall TRUE  *)

end