MS-DOS's debugger DEBUG.EXE did only support the assembly/disassembly of 8086 opcodes. DR-DOS's debugger SID86.EXE, SID.EXE and Novel's debugger DEBUG.EXE did support 80286 opcodes and more, but no AMD, Cyrix, NEC etc. specialties.
So I'm wondering if the CPU manufacturers like AMD, NEC, Cyrix and others provided their own debugger for DOS and if so, if it was offered as Freeware or did it cost money?
Edit: I took the liberty of clarifying the question a bit.
In the DOS days, there were CPU manufacturers like NEC that had additional opcodes in their V20/V30 CPUs which where compatible replacements for the Intel 8080 and 8086. And Cyrix and IIT had extensions in their CPUs and co-processors.
Therefore, it would have made sense for these CPU manufacturers to better support their CPUs and FPUs with their own debugger, allowing developers to take advantage of their additional features and make their CPU and coprocessor products look better in tests.