Table of Contents

ugBASIC User Manual

DECLARE PROCEDURE ✓

SYNTAX

   DECLARE [SYSTEM] PROCEDURE name AT address [ ( par [, par [, ... ] ] ) ] [ ON targets ]
     par : name AS type ON register
     par : name AS type ON STACK(width)
     width: BYTE | WORD | DWORD
     targets : name of targets, separated by comma (,)

PURPOSE

The DECLARE PROCEDURE is a way to define and call external procedures written in machine language and to insert assembly into the sources. The procedures defined in this way can be called as if they were an integral part of the language. Once the procedure has been declared, it will be sufficient to invoke it with one of the following syntaxes: 

'''CALL test'''
'''PROC test'''
'''test[]'''

as if it were any ugBASIC procedure. If desired, parameters can be added. For each it is obviously necessary to indicate how the value will be passed to the function written in machine language.

The ugBASIC compiler allows you to declare functions and procedures that are “system”. It means that the machine code resides in a ROM, preloaded at run time and therefore already made available to any program that knows how to call it.

However, since ugBASIC makes available all memory space allowed by the hardware, it is possible that the ROMs have been disabled or otherwise made unreachable. Indicating that you want to call a procedure or a system function, ugBASIC will take care of re-enabling the ROM before executing the request, deactivating it on exit.

To declare a procedure or function to be system, simply use the SYSTEM keyword.

EXAMPLE

  DECLARE SYSTEM PROCEDURE test ON CPC, ZX

See also the following example files:

ABBREVIATION

 DecPrcd

AVAILABLE ON

SEE ALSO

DECLARE FUNCTION

ALIAS FOR

DECLARE PROC

ANY PROBLEM?

If you have encountered a problem using this command, if you think there is a bug or the explanation is unclear, please open an issue for this keyword on GitHub. Thank you!

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