Using CodeView /2, Hercules Graphics Cards and Libraries

MS-DOS                             | WINDOWS

The information in this article applies to:

• Microsoft CodeView for MS-DOS, versions 2.2, 3.0, 3.11, 3.14, 4.0, 4.01, 4.05, and 4.1
• Microsoft CodeView for Windows, versions 3.0, 3.05, 3.06, 3.07, 4.0, 4.01, and 4.1

SUMMARY

Using CodeView in the dual-monitor mode with a Hercules graphics card as the primary (application) monitor requires the Hercules card to be configured in the half mode. Using the Hercules graphics library, the monitor must be configured using the config(0) function call. This function call is a part of the Hercules graphics library and does not use Microsoft graphics library or the MSHERC.COM program. Therefore, this information applies only if you are using the Hercules graphics libraries. This is NOT the same as using the /h switch with MSHERC.

MORE INFORMATION

The first page of the Hercules graphics display card is mapped to memory location B0000 (same as MDA), and the second page is mapped to B8000. The CGA/EGA/VGA also use B8000 as the beginning of their video memory. CodeView uses these two different address to run in the dual- monitor mode, sending the application output to the primary address, usually located at B8000, and the CodeView information to the secondary monitor, usually located at B0000.

This works well until a Hercules graphics card is used as the primary monitor (in graphics mode) and the CGA/EGA/VGA card is used as the secondary monitor. The Hercules graphics card uses both pages (one at B0000 and the other at B8000) in the full mode. Therefore, use config(0) and only the first page (B0000) will be used and CodeView will function properly in dual-monitor mode.