There are quite a few text messages in the code, like "Stack overflow, try more P switches",
"Fatal error(s)" and "REPT/IRP/IRPC/MACRO".
These appear to come from ASM.COM:
which is a CP/M assembler, and was presumably used to build
the production binary.
No use of alternate registers
The code doesn't use the Z80's alternate register set. There is no EXX or EX AF,AF'
anywhere in it.