[COFF] Re: machine code translation,as mental architecture models

On 7/13/24 19:46, John Levine wrote: Possibly, but they use 'syllables' for tokens (symbols or integers), and they say here that they advance the location counter after each word copied.  If they were copying characters into the input stream, they would not be incrementing the location counter ('.') after each word transferred. And as you say, it is simple parameter substitution, so tracking which macro argument goes into which instruction's address field is easy.  The instruction format is simple.  So for each line in the macro definition body, if the opcode is a memory reference instruction, put the argument number in the binary instruction address field before storing the instruction word in a list/block. When expanding the macro, if the opcode is a memory reference instruction, get the argument number from the address field and replace it with the symbol table value of the symbol passed in as the actual argument, and store the word in the output stream (and incrememnt '.'). I haven't yet gotten the 18-bit-but-incompatible PDP-4 documentation for comparison.  [IIRC the PDP-4 assembler was the one with a single pass assembler that punched the symbol table at the end of the tape, and the clever loader that read the tape upside down and backwards to first rebuild the symbol table and then fix up the instructions and load them into memory.] - Aron