DOCUMENT:Q39373  04-MAY-2001  [masm]
TITLE   :FIX: Warning A4057 Generated Instead of Error A2019
PRODUCT :Microsoft Macro Assembler
PROD/VER::5.1
OPER/SYS:
KEYWORDS:

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Macro Assembler (MASM), version 5.1 
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SYMPTOMS
========

The code below is correctly flagged as an error in the Microsoft Macro Assembler
(MASM) versions 5.0, 6.0, 6.0a, 6.0b, but MASM 5.1 generates a warning and
incorrect code.

The following is the error generated by MASM 5.0

   A2019: Wrong type of register

Macro Assembler Version 5.1 fails to generate an error on the MOV instruction
using the 8-bit registers (AH, BH, CH, DH, AL, BL, CL, DL) with segment
registers (CS, DS, ES, SS). Instead, the following warning is generated

   A4057: Illegal size for operand

The code generated is also in error. Each of the (8-bit) byte registers maps to
the set (SP, DI, BP, SI, AX, BX, CX, DX).

The following is the error generated by MASM 6.0

   A2024: invalid operand size for instruction

STATUS
======

Microsoft has confirmed this to be a problem in MASM version 5.1. This problem
was corrected in MASM version 6.0.

MORE INFORMATION
================

The following sample code demonstrates the problem:

Sample Code:
------------

   ;Assemble options needed: none

   _TEXT   segment word public 'CODE'
         ; instruction in source     Generated code shown in listing
           mov     ds, ah          ; mov   ds, sp
           mov     ds, bh          ; mov   ds, di
           mov     ds, ch          ; mov   ds, bp
           mov     ds, dh          ; mov   ds, si

           mov     ds, al          ; mov   ds, ax
           mov     ds, bl          ; mov   ds, bx
           mov     ds, cl          ; mov   ds, cx
           mov     ds, dl          ; mov   ds, dx

           mov     ah, 4ch
           int     21h
   _TEXT   ends
           end

Additional query words: 5.10 buglist5.10 fixlist6.00

======================================================================
Keywords          :  
Technology        : kbMASMsearch kbAudDeveloper kbMASM510
Version           : :5.1
Solution Type     : kbfix

=============================================================================

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