Configuring Extended Memory for the CodeView Debugger

Extended memory is the memory above the first megabyte that an 80286, 80386, or 80486 can access in protected mode. (Extended memory is not the same as expanded memory. Expanded memory is bank-switched memory that overcomes the 640K RAM limit of machines with 8086/8088 processors.)

To use the extended memory features of the CodeView debugger under DOS, you must first add DEVICE=HIMEM.SYS (with HIMEM's full pathname) to the CONFIG.SYS file, then reboot. The NEW-CONF.SYS file created by SETUP contains a sample HIMEM entry.

NOTE:

HIMEM.SYS implements the XMS 2.x standard. The complete XMS source and specification are available from the Microsoft Information Center.

There are several additional factors to consider when using extended memory with CodeView under DOS or Windows:

CodeView needs at least 384K of extended memory. If you add memory to your computer, be sure to configure at least 384K of it as extended memory.

Older versions of HIMEM.SYS may not work properly with this product. Use the version of HIMEM.SYS on the MASM 6.0 distribution disks.

Other memory managers such as 386-Max or QEMM may conflict with HIMEM.SYS. Don't install more than one memory manager.

Don't use HIMEM.SYS (or any other memory manager) with Windows/386. Windows/386 allocates extended and expanded memory automatically.

If you run Windows 3.0 in 286-Protected mode, create a PIF for CodeView and specify at least 384K of XMS (extended) memory.

Many RAM-disk and disk-cache programs are incompatible with HIMEM.SYS. The RAMDRIVE and SMARTDRV programs supplied on the distribution disks are HIMEM.SYS-compatible.

If you run TSRs, check their documentation to see if they are compatible with HIMEM/XMS 2.x. If there is any question about compatibility, manually install one TSR at a time.

SETUP places the HIMEM, RAMDRIVE, and SMARTDRV drivers in the
C:\MASM\BIN directory or in the directory you have specified for real-mode executable files.