Utility for converting gbz80 ASM/opcodes into an item list for use with 8F.
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8F Helper

A quick and dirty (but fast!) application in C that uses lookup tables to assist in the creation of item lists for use with the 8F item in Pokemon R/B/Y. It's got a small amount of error handling and supports the use of a single label for jumping.


You can download the latest version of the 8F Helper on the releases page.


Usage: gbz80aid [options] [hex]

  -f file      File mode (read input from file)
  -o format    Display output in a specific format
  -ofs offset  Specify memory offset to display in asm format.
                 (Ignored in other formats)
  -w           Disable item warning messages
  -h           Print this help message and exit
  -v           Print version information and exit

  asm          GB-Z80 assembly language
  bgb          BGB-style assembly language
  hex          Hexadecimal machine code format
  joy          Joypad values
  gen1         R/B/Y item codes for use with ACE
  gen2         G/S/C item codes for use with ACE

  gbz80aid EA14D7C9
  gbz80aid -o asm -f bgb_mem.dump
  gbz80aid -o hex -f zzazz.asm
  gbz80aid -o gen1 0E1626642EBB4140CDD635C9
  gbz80aid -o gen2 -f coin_case.asm



di               ; Kill all interrupts

.testJump        ; Just to show the label/jump processing
dec a
inc a
inc b
jr c, testJump   ; Relative jump to label

ld h, $FF        ; Set hl to $FF00
inc b
xor l

ld a, $20        ; Enter STOP mode until D-pad is pressed
inc c
ld (hl), a

ret              ; Continue normal execution 

Program outputs

root@gbdev:~# gbz80aid -o hex -f test_code.asm

Machine code: F33D3C0438FB26FF04AD3E200C771001C9
root@gbdev:~# gbz80aid F33D3C0438FB26FF04AD3E200C771001C9

gbz80 Assembly:

   0  F3               di
   1  3D               dec  a
   2  3C               inc  a
   3  04               inc  b
   4  38 FB            jr   c,$FB
   6  26 FF            ld   h,$FF
   8  04               inc  b
   9  AD               xor  l
   A  3E 20            ld   a,$20
   C  0C               inc  c
   D  77               ld   (hl),a
   E  10 01            stop
  10  C9               ret
root@gbdev:~# gbz80aid -o gen1 -f test_code.asm

Item            Quantity
TM43            x61
Fresh Water     x4
Super Repel     x251
Carbos          x255
Poke Ball       x173
Lemonade        x32
Burn Heal       x119
Full Restore    x1
TM01            xAny


I've opted to use 10 01 as the STOP opcode instead of the correct 10 00. This is because it's much easier to get 1 of an item rather than 0 of an item. In all tests, the STOP instruction executes normally even with a non-zero argument.