Have any good sources of this topic of macro assemblers? I'm interested in reading about this type of thing. I'll search Google, but you can't always find good sources there today.
"Assembly language for the PC"
https://archive.org/details/assemblylanguage00soch
"TASM Reference"
https://archive.org/details/bitsavers_borlandturemblerVersio...
"Structured Assembler Language For IBM Microcomputers"
https://archive.org/details/structured-assembler-language-fo...
Or just go to MASM documentation, you will find plenty of directives that look like an high level language
https://docs.microsoft.com/en-us/cpp/assembler/masm/directiv...
Put "360 assembler macros" in your search engine and you'll find lots of information.
This is a good place to start: https://www.ibm.com/docs/en/zos/2.1.0?topic=language-macro-i...