Q34466: MASM 5.10 MACRO.DOC: Calling Macros in DOS.INC, BIOS.INC

Article: Q34466
Product(s): See article
Version(s): 5.10   | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | | mspl13_masm
Last Modified: 12-JAN-1989

The following information was taken from the MASM 5.10 MACRO.DOC file.

Calling Macros in DOS.INC and BIOS.INC

You are responsible for saving and restoring registers used in macros.
The "Registers used" field identifies registers to save.

Macros that accept address parameters use internal macros that allow
you to specify addresses in several ways. The macro automatically
identifies the type of the argument and handles it appropriately. For
example, assume the following declarations:

  String    DB   "test$"
  pString   DW   Str
  fpString  DD   Str

Given these values, the macro @DispStr (which displays the string at
DS:DX) has the following effects:

  Kind of argument          Example               Value loaded

  Label of byte variable    @DispStr String       DS:OFFSET String
  Near pointer variable     @DispStr pString      DS:pString
  Far pointer variable      @DispStr fpString
  fpString[2]:fpString[0]
  Constant                  @DispStr 0            DS:0
  Pointer in register       @DispStr si           DS:SI
  Near Pointer with segment @DispStr pString,es   ES:pString
  Constant with segment     @DispStr 0,es         ES:0
  Register with segment     @DispStr di,es        ES:DI

Note that if a far pointer or a segment is given, DS must be saved
before the macro call and restored afterward. Segments may be given as
registers, constants, or word variables.

In syntax, parameters enclosed in brackets are optional. Paramaters
sometimes have a leading symbol to indicate that the argument must
have a certain type, as shown below:

  Leading Symbol   Example      Limitation

        #          #return      Must be constant
        &          &vector      Must be offset address as described
                                above
        $          $terminator  May be constant or register, but not
                                memory

Parameters with no leading symbol may be constants, registers, or
variables. Parameters are 16-bit except where noted in the
description.

Symbols must be previously defined before they can be passed as
arguments to most of the DOS macros. Generally this means that data
must be declared before code in the source file.

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