Does Turbo Assembler or MASM come with an IDE?

[Roger Wilco]

I'm unable to assure you about such „complete” compatibility; according to docs it's highly compatible to MASM (and some other assemblers), but you can download the free version (which isn't limited nor crippled!) and test it by yourself. In case of doubts you can also contact the Author (yes, he's „responsive”).
Of course this is different assembler (it's not any „clone” of MASM/TASM); my suggestion came from the fact, that OP seems to be going to use as slow gear, as XT. In such case something as fast, as A86 is, of course makes the work easier.

 

[Chuck(G)]

Thanks, but after thousands of lines of MASM/ML, i'm not particularly eager to try another one. Where a lot of assemblers fail in compatibility is with the pseudo-ops and macros and 64-bit support. Opdefs and strong typing are two more stumbling blocks. I've used MASM since the terrible 1.0--still have the manual and disk.

 

[Roger Wilco]

Thanks, but after thousands of lines of MASM/ML, i'm not particularly eager to try another one.

In such case indeed it could mean additional effort (and rather significant) — and another problem could be that while A86 has its A386 version, but I'm not sure whether Eric released any 64-bit version (maybe, but I didn't make any inquiry about that; the highest CPUs mentioned in the docs are Pentium III and Athlon).
But my suggestion was rather directed to OP, who was asking about „coding [in] assembler in DOS for a PC-XT”. A86 is probably the fastest x86 assembler around (it's written directly in ML, according to Eric).