Q65591: Screen Output Fails When Using Animate with Assembly Files

Article: Q65591
Product(s): See article
Version(s): 2.51
Operating System(s): MS-DOS
Keyword(s): ENDUSER | buglist2.51 | mspl13_masm
Last Modified: 17-OCT-1990

While debugging an assembler program under Microsoft QuickAssembler
version 2.51, if Animate is selected from the Run menu, the code below
will not print anything to the output screen if Screen Swap is set to
On in the Options Run/Debug menu.

Sample Code
-----------

        TITLE   HELLO
        .MODEL  small, c
        DOSSEG

        .STACK  100h

        .DATA
msg     DB      "Hello, world.", 13, 10, "$"

        .CODE
        .STARTUP

        mov     ah, 9h
        mov     dx, OFFSET msg

        int     21h

        .EXIT   0

        END

The following are three valid workarounds:

1. In the Run menu, disable Animate.

2. Make sure Screen Swap is set to On, and then trace (F8) or Step
   (F10) through the program instead.

Microsoft has confirmed this to be a problem with QuickAssembler
version 2.51. We are researching this problem and will post new
information here as it becomes available.