Error on BIOS disassembly

[kdridi]

I tried to disassemble the BIOS using this (nice) tool.

I create the cartridge using this python3 script

#!/usr/bin/env python3

code = bytearray([
    0x31, 0xFE, 0xFF, 0xAF, 0x21, 0xFF, 0x9F, 0x32, 0xCB, 0x7C, 0x20, 0xFB, 0x21, 0x26, 0xFF, 0x0E,
    0x11, 0x3E, 0x80, 0x32, 0xE2, 0x0C, 0x3E, 0xF3,  -- snip --
])

rom = code + bytearray([0x00] * (32768 - len(code)))

with open("bios.gb", "wb") as out_file:
  out_file.write(rom)

The mgbdis creates some files but when I looked in bank_000.asm, I found is an error

; Disassembly of "bios.gb"
; This file was created with:
; mgbdis v1.4 - Game Boy ROM disassembler by Matt Currie and contributors.
; https://github.com/mattcurrie/mgbdis

SECTION "ROM Bank $000", ROM0[$0]

RST_00::
    ld sp, $fffe
    xor a
    ld hl, $9fff

jr_000_0007:
    ld [hl-], a

RST_08::
    bit 7, h
    jr nz, jr_000_0007

    ld hl, $ff26
    db $0e  ;  <<<<<<<<<<<<<< ERROR

RST_10::
    ld de, $803e
    ld [hl-], a
    ld [c], a
    inc c
    ld a, $f3

The tool seems to skip the disassembly of the 0x09 opcode (LD c, n) that has to consume an other byte.

[mattcurrie]

For disassembling boot ROMs you will want to remove the default symbols on the lines linked below, as they force mgbdis to have instructions starting at those addresses:

mgbdis/mgbdis.py

Lines 21 to 47 in b41f5c8

	'00:0000 RST_00',
	'00:0000 .code:8',
	'00:0008 RST_08',
	'00:0008 .code:8',
	'00:0010 RST_10',
	'00:0010 .code:8',
	'00:0018 RST_18',
	'00:0018 .code:8',
	'00:0020 RST_20',
	'00:0020 .code:8',
	'00:0028 RST_28',
	'00:0028 .code:8',
	'00:0030 RST_30',
	'00:0030 .code:8',
	'00:0038 RST_38',
	'00:0038 .code:8',
	'00:0040 VBlankInterrupt',
	'00:0040 .code:8',
	'00:0048 LCDCInterrupt',
	'00:0048 .code:8',
	'00:0050 TimerOverflowInterrupt',
	'00:0050 .code:8',
	'00:0058 SerialTransferCompleteInterrupt',
	'00:0058 .code:8',
	'00:0060 JoypadTransitionInterrupt',
	'00:0060 .code:8',

It would be nice if there was an option to disable these for cases where they aren't relevant :)

(Also note I've just edited your issue to remove the bulk of the boot ROM file).