cxw42 / do-not-self-host Goto Github PK

Because it would be nice to have while reading traces.

• ngbasm: Emit the symbol<->address map
• ngb: Read the map if present in an input file
• ngb: while printing trace output, also print the symbol name if any matches.

• Make MCVE
• Report it upstream to Data::DFA

See linked commit for more.

• Tokenizer (currently regex-based)
• Table-driven parser
• Bytecode generator

E.g., so this will work:

:global_var
    .data 42
.scope
    :local1_var
         .data 1
    fetch &global_var    ; OK
    fetch &local1_var    ; OK
    fetch &local2_var    ; assembly-time error - not in scope
.endscope
.scope
    :local2_var
         .data 2
    fetch &global_var    ; OK
    fetch &local1_var    ; assembly-time error - not in scope
    fetch &local2_var    ; OK
.endscope

General:

• Add Makefile

VM:

• Rename nga->ngb (to avoid confusion). (Note: I'm basing ngb on nga rather than retro since nga is much simpler, and I will eventually be implementing the VM in x86 assembly.)
• Add in, out instructions (currently in ngaita.c)
• Add err instruction to output to stderr (since we're going to want that for the toolchain)
• Add iseof (push (TOS == -1) ? -1 : 0); leave the character on the stack)
• Rename cjump to ccall, since that's what it is in nga.c
• Add real cjump
• Add dedicated counter variable and setcount/getcount instructions
• Add loop &label a la x86 (because it's a nice, convenient thing to have).

  • I think this should be loopcheck &done_label so you can put it at the top of the loop, since most of the loops I have written have been top-check. The resulting loop would look like:

        setcount 5
    :loop
        loopcheck &loop_done    ; branch if counter==0; otherwise, decrement counter.
        getcount
        outnum
        jump &loop
    :loop_done
    

Assembler:

• Permit comments in asm source files
• Add .include directive
• Add .lit <n> directive that emits a lit <n> instruction.
• Change syntax so that any operand becomes a lit <n> before the instruction. E.g., cjump &done is assembled to lit, &done, cjump. Or eq 32 becomes lit, 32, eq. (This requires more care on the programmer's part with stack discipline :) .)