Microsoft MASM 6.0

Microsoft MASM 6.0 added high level language constructs such as IF, WHILE and REPEAT alongside some further loop controls, also the first MASM version to support LR offsets, fully flat 32 bit memory and the full Intel 80486 instruction set. The engine had also been re-written so it now performed all passes in memory rather than off disk and supports DPMI memory management, but no longer runs in severely memory constrained DOS systems. Version 6 also added some automatic memory range fixes.

It's the last version that supports OS/2 fully, can generate flat 32-bit code for OS/2, DOS (using a supplied DOS extender) and Windows. Microsoft MASM 6.1 was no longer OS/2-hosted.

Version

 * 6.0 (1991)
 * 6.0a
 * 6.0b (1992)

Links

 * Microsoft KB: Creating 32-Bit Flat Memory Model MASM Code for OS/2 2.0