asmsplit.py

#!/usr/bin/env nix-shell
#! nix-shell -i python3 -p python3
#
# Usage: ./asmsplit.py MAPFILE < ASMFILE

import os
import re
import sys

basedir = 'asm/'
macros = 'macros.inc'

filenames = {}
lastfile = None

with open(sys.argv[1]) as mapfile:
    for mapline in mapfile:
        match = re.match(
            '  [0-9a-f]{8} [0-9a-f]{6} ([0-9a-f]{8}) [0-9a-f]{8} [ 0-9][0-9] [^ ]+ \t(.+)',
            mapline)
        if match and match.group(2) != lastfile:
            lastfile = match.group(2)
            addr = int(match.group(1), 16)
            fname = basedir + '/'.join(
                map(lambda s: os.path.splitext(s)[0],
                    match.group(2).strip().split(
                        ' '))) + f"_{hex(addr)[2:]}" + '.s'
            filenames[addr] = fname

curfile = open(macros, 'w')
curaddr = 0
section = ''
remainder = None

while asmline := remainder or sys.stdin.readline():
    remainder = None
    trim = asmline.strip()
    if trim.startswith('.section'):
        ex = trim.split("#", 1)
        comment = ex[1]
        ex = comment.split(" ")
        curaddr = int(ex[1], 0)
        section = asmline
        curfile.close()
    else:
        if trim != "":
            if curfile.closed:
                fname = filenames[curaddr]
                if os.path.exists(fname):
                    curfile = open(fname, 'a')
                    curfile.write('\n')
                else:
                    os.makedirs(os.path.dirname(fname), exist_ok=True)
                    curfile = open(fname, 'x')
                    curfile.write('.include "' + macros + '"\n\n')

                curfile.write(section)
            if trim.startswith("#"):
                continue
            if trim.startswith('.skip'):
                curaddr += int(trim[6:], 0)
            elif trim.startswith('.incbin'):
                f, a, s = asmline.split(', ')
                a = int(a, 0)
                s = int(s, 0)
                if s < 0: raise ValueError()
                elif s == 0: continue

                k = 1
                while (curaddr + k) not in filenames and k < s:
                    k += 1
                curaddr += k

                if k < s:
                    asmline = f + ', 0x' + format(a, 'X') + ', 0x' + format(
                        k, 'X') + '\n'
                    remainder = f + ', 0x' + format(
                        a + k, 'X') + ', 0x' + format(s - k, 'X') + '\n'
            elif trim.startswith(".balign"):
                _, alignment = asmline.split(' ')
                alignment = int(alignment)
                if curaddr % alignment != 0:
                    curaddr += 4 - (curaddr % alignment)
            elif not trim.startswith('.global') and not trim.endswith(':'):
                if trim.startswith(".2byte"):
                    curaddr += 2
                elif trim.startswith(".byte"):
                    parts = trim.count(",") + 1
                    curaddr += parts
                else:
                    curaddr += 4

        if not curfile.closed: curfile.write(asmline)

    if curaddr in filenames and filenames[curaddr] != curfile.name:
        curfile.close()