Game Boy Advance SDK Demos

Edit on Github | Updated: 28th March 2021

Version 3.0 of the Game Boy Advance Software Development Kit (SDK) was leaked on to the internet for everyone to enjoy.

There are some very interesting findings in this SDK, but this post will cover something particularly interesting, the demo games developed by Nintendo to show off the power of the GBA to developers.

If you look in the src/demos folder you will find two pretty cool GBA game source code projects. One is a Yoshi’s Story example and the other is called Dolphin featuring Ricky the Dolphin!.

Dolphin Demo

Dolphin is a demo game for the Game Boy Advance with very strong similarities to the Ecco the Dolphin series. You control a Dolphin called Ricky and can move through the water and go through rings. It is simple but a very nice tech demo for the possibilities of the GBA hardware.

You can see it in action in the video below:

This folder contains the main source code and build scripts required to compile the Dolphin example into a working GBA ROM.

File Name	Extension	Description
Agb_c2_s	.bat	Window Batch script to use Cygwin GCC to compile main.c
Gasdepend	N/A	Lists dependencies for the GNU assembler to know when to reassemble crt0.s
Makedepend	N/A	Lists dependencies to tell Make when to re-compile files
Makefile	N/A	Main Makefile used to build the project
bg	.c, .h, .o	Code for drawing Background images, such as water and coral floor
crt0	.o, .s	Implements the start function and bootstraps the program, all GBA games need this as it sets up the interrupts and jumps to the main function
dolphin	.bin, .elf, .map	The generated game in both ELF and .bin (GBA ROM) formats, along with the linker map file containing all the final locations of code inside the game
dolphin_readme	.txt	A Brief introduction to the game and how to play it
enemy	.c, .h, .o	Main enemy logic such as drawing and hit detection
enemy_dat	.c, .o	Enemy animation data (references images for each frame)
game_dat	.c, .o	Just contains pre-computer sin and cos tables
gdbrc	N/A	Configuration for the GNU debugger for debugging the game
hitcheck	.c, .h, .o	Main collision detection logic
main	.c, .h, .o	This contains the AgbMain function which starts the game along with the other main game logic
player	.c, .h, .o	Main player logic such as drawing and moving
player_dat	.c, .o	Just contains player animation data, references to each of the images used and the delay of each frame
ring	.c, .h, .o	Contains all the logic for the rings, including drawing them and what happens when the dolphin moves through them
rom_header	.s	Assembly code that implements the common GBA ROM reader required of all GBA ROMs

Code Files

bg.c

BgAnmPat[4] wave2nd_pat
Bg Light
Bg Coral
Bg OceanA
Bg OceanB
Bg Sky
u16[1024] UmiA_ScreenDat
u16[1024] Bg2_ScreenDat
u16[1024] Sky_ScreenDat
u16[1024] Sango_ScreenDat
s32 ocean_xPos
s32 sora_xPos
u8 DisplayArea
BgAnm wave2nd
void initwave2nd(BgAnm*)
void Anm_wave2nd(BgAnm*)
void InitBg()
void BgProc(s32,s32)
void Change_Bg_VRAM(s32,s32)
void UpdateBg(s32,s32)
void InitSky()
void Init_Sky_ScreenDat()
void DrawSky(s32,s32)
void DeleteSky(s32,s32)
void SoraRight()
void SoraLeft()
void InitCoral()
void InitCoralScreenDat()
void DrawCoral(s32,s32)
void DeleteCoral(s32,s32)
void CoralRight()
void CoralLeft()
void CoralUpDown()
void InitLight()
void InitLightScreenDat()
void DrawLight(s32,s32)
void DeleteLight(s32,s32)
void InitOceanA()
void InitOceanAScreenDat()
void OceanA_Idle(Bg*,s32,s32)
void DrawOceanA(s32,s32)
void DeleteOceanA(s32,s32)
void OceanA_Up(Bg*)
void OceanA_Down(Bg*)
void InitOceanB()
void InitOceanBScreenDat()
void DrawOceanB(s32,s32)
void DeleteOceanB(s32,s32)
void OceanB_Up()
void OceanB_Down()

790

enemy.c

Enemy[10] dEnemy
Awa[16] awa
Fukiya[4] fukiya
u32 const[1][2] Oam_def
u32 const[1][2] Oam_32x32dot
u32 const[1][2] Oam_16x16dot
u32 const[1][2] Oam_8x8dot
u8[12] anm_state
void InitEnemy()
void EnemyProc()
void CreateTeki(Enemy*,CharMapData*)
void HitCheck_Enemy(Enemy*)
void HitEnemy(Enemy*)
void DeadCheckEnemy(Enemy*)
void ControlEnemyMove(Enemy*)
void MoveShell1(Enemy*,u8)
void MoveShell2(Enemy*,u8)
void ShellAttackMove(Enemy*,u8)
void DeadMove(Enemy*,u8)
void LcdCheckEnemy(Enemy*,Player*)
void ShellAnim(Enemy*)
void ShellBaseAnim(Enemy*)
void ShellAttackAnim(Enemy*)
void ShellDamageAnim(Enemy*)
void ShellDeadAnim(Enemy*)
void DrawEnemy(OamData*,Enemy*)
void EraseEnemy(OamData*,Enemy*)
void InitAwa()
void AwaProc()
void CreateAwa(Enemy*)
void AwaMove(Awa*)
void DrawAwa(OamData*,Awa*)
void InitFukiya()
void FukiyaProc()
void CreateFukiya(Fukiya*,Enemy*)
void FukiyaMove(Fukiya*)
void DrawFukiya(OamData*,Fukiya*)

733

enemy_dat.c

u8 const*[10] shell_base_pix_tbl
Anmpat[10] shell_base_anm_pat
u8 const*[21] shell_attack_pix_tbl
Anmpat[13] shell_attack_anm_pat
u8 const*[21] shell_yarare_pix_tbl
Anmpat[21] shell_yarare_anm_pat
CharMapData[12] shell_map_dat
Enemy_Oam_Data[10] enemy_Oam_Data

143

game_dat.c

u32 const[1][2] Oam_16x8dot
u32 const[1][2] OamData_Sample
short[256] sin_tbl
short[256] cos_tbl
u8[256] sintable

112

hitcheck.c

void Fukiya2Dolphin(Player*,Fukiya*)
void Dolphin2Enemy(Player*,Enemy*)
void Ring2Dolphin(Ring*,Player*)
u8 RingPass(Ring*,Player*)

201

main.c

vu16 IntrCheck
u16 Cont
u16 Trg
u32[512] IntrMainBuf
ObjBuf Oam
u8[256] rasttable
u8 v_phase
s8 amp_r
s8 hz
u8 state
s16 counter
u8 offset
void(*[2])() pGame_func_tbl
IntrFuncp const[15] IntrTable
void AgbMain()
void VBlankIntr()
void HBlankIntr()
void VCountIntr()
void IntrDammy()
void KeyRead()
void GameInit()
void GameMain()
void GameOver()

325

player_dat.c

u8 const*[6] r_kihon_pixel_tbl
u8 const*[8] r_kihon_idle_pixel_tbl
u8 const*[6] r_attack_pixel_tbl
u8 const*[9] r_down_pixel_tbl
u8 const*[29] r_up_down_pixel_tbl
u8 const*[19] r_jump_pixel_tbl
AnmTable2[7] rick_normal_move_pat
AnmTable2[8] rick_kihon_idle_pat
AnmTable2[19] rick_jump_anm_pat
AnmTable[6] rick_attack_pat
AnmTable[11] rick_kihon_fast_pat
AnmTable[25] rick_jump_pat

270

player.c

Player player
Player_Awa[4] player_awa
void InitPlayer()
void PlayerProc()
void DrawPlayer()
void RestrictPlayerPosition(Player*)
void PlayerActionControl()
void Chang_Dir(Player*)
void MovePlayer()
void ChangeWaterSpeed()
void Action1()
void JumpPlayer()
void Action3()
void InitPlayerAnim()
void PlayerAnim()
void Player_kihon_anm()
void Player_kihon_idle_anm()
void Player_updown_anm()
void Player_jump_anm()
void Player_idle_anm()
void Player_attack_anm()
void Player_move_rl_anm()
void Player_head_attack_anm()
void Ajust_Light_Reflection(Player*)
void BlinkPlayer(Player*)
void InitPlayer_Awa()
void Player_AwaProc()
void CreatePlayer_Awa(Player_Awa*,Player*)
void Player_AwaMove(Player_Awa*,Player*)
void DrawPlayer_Awa(OamData*,Player_Awa*)

852

ring.c

Ring[20] ring
RingMapData[30] ring_map_dat
u32 const[1][2] Oam_32x64dot
void InitRing()
void RingProc()
void RingStateControl(Ring*)
void CreateRing(Player*)
void DrawRing(Ring*)
void RingNormal(Ring*,u8)
void RingPassed(Ring*,u8)
void RingHit(Ring*,u8)

260

Dolphin/Doc

This folder contains a brief document describing the Dolphin demo and the features it shows off.

The document is simply called DemoProgramDolphin.doc, it is only 2 pages long and mainly contains details about how to play the game.

However there are a few interesting parts including a very basic UML diagram for the game flow created in Microsoft Word.

The document mentions a few key features of the demo:

Usage of light reflections for the dolphin underwater
Character animation via DMA transfer to VRAM
H-Blank raster scroll processing

It’s funny how in the game source code the Dolphin’s name is Ricky but they only refer to him a “Dolphin” in the document, why give him a name like Ricky in the first place?

Bg_parts (dolphin/bg_parts)

This folder contains each part of the Background that makes up the game, in the original BMP format and the converted C source code equivalent and its compiled object.

The BMP files are the only files of interest here as they would be fed to a tool called bmp2map that automatically converts it to a C-file (basically just encodes each byte of the BMP as an element of an array in C). The generated C files would then be compiled using the standard GBA toolchain compilers (GCC) and the object file (.o) would be created as the result.

These object files would then be linked with the rest of the game code to generate the final ELF executable of the game, which would then be converted to a valid GBA ROM, whew!

File Name	Extension	Description
light4	.bmp, .c, .o	A texture used to map on to Ricky when he is swimming under water to mimic underwater light
sango1024x256	.bmp, .c, .o	The Coral right at the bottom of the sea
sora	.bmp, .c, .o	The sky image
umiA_	.bmp, .c, .o	water image
umi_ab_256x512	.bmp, .c, .o	Contains the water and sea floor
wave2nd1	.bmp, .c, .o	Wave image used for animating at the top of the water
wave2nd2	.bmp, .c, .o	Wave image used for animating at the top of the water
wave2nd3	.bmp, .c, .o	Wave image used for animating at the top of the water

Images (dolphin/img)

This folder contains all the sprite images used in the game. In the foot folder we have a few Misc sprites such as a bubble and the ring sprites, most of the other sprites are in the Oumgai and Ricky folders.

File Name	Extension	Description
awa	.bmp	Bubble sprite
ring_32_64_left	.bmp	left sprite of the ring
ring_32_64_right	.bmp	right sprite of the ring

Oumgai sprites (dolphin/img/Oumgai)

In the Oumgai folder we have tons of animation frames for a sea creature known as a Nautilus in English and Oumgai in Japanese.

These are all in BMP but the resulting .c and .o files are in the dolphin/Obj folder.

File Name	Extension	Description
/Oumgai/O_fukiya	.bmp	A pink japanese Blowgun?!
/Oumgai/O_kihon/O_kihon00(0-10)	.bmp	Normal animation frames
/Oumgai/O_kougeki/O_kougeki000(0-20)	.bmp	Animation frames of movement
/Oumgai/O_yarare/O_yarare0(0-20)	.bmp	Animation frames of movement

Ricky sprites (dolphin/img/Ricky)

In the Ricky folder we have tons of animation frames for the Ricky sprite, moving up/down/jumping etc.

These are all in BMP but the resulting .c and .o files are in the dolphin/Obj folder.

File Name	Extension	Description
/Ricky/R_attack/R_attack(0-7)	.bmp	This folder contains animation frame of Ricky’s right attack
/Ricky/R_down/R_down(0-8)	.bmp	This folder contains animation frames of Ricky looking down.
/Ricky/R_up/R_up(0-8)	.bmp	This folder contains animation frames of Ricky looking up.
/Ricky/R_go_down/R_go_down(0-7)	.bmp	This folder contains animation frames of Ricky moving down
/Ricky/R_go_up/R_go_up(0-7)	.bmp	This folder contains animation frames of Ricky moving up
/Ricky/R_jump/R_jump(0-10)	.bmp	This folder contains animation frames of Ricky jumping
/Ricky/small/r_small(0-7)	.bmp	This folder contains small images of Ricky, not currently sure why
/Ricky/R_kihon/R_kihon(0-7)	.bmp	This folder contains animation frames of Ricky moving forward

Obj (dolphin/obj)

This folder contains the generated output of all the image folder’s BMP files, the GBA SDK tends to refer to Sprites as Objects hence the name of this folder.

These were generated by a tool called bmp2agb and then compiled from .c to .o in order to be linked into the final game.

There is no point in listing these files as they are exactly the same as the BMP files listed in the IMG folder.

Yoshi (/yoshi)

This folder contains a demo game based on the Nintendo 64 title Yoshi’s story, this was a very impressive example running on the GBA hardware.

You can see it in action in the video below:

All the source code is here to build the example yourself and it makes an excellent project to learn how to reverse GBA games as you can see the original source code.

File Name	Extension	Description
Gasdepend	N/A	Lists dependencies for the GNU assembler to know when to reassemble crt0.s
Makedepend	N/A	Lists dependencies to tell Make when to re-compile files
Makefile	N/A	Main Makefile used to build the project
Readme	.txt	Fairly detailed instructions for the game and how to build it
bg_proc	.c, .o	Logic for drawing the background layers
crt0	.o, .s	Implements the start function and bootstraps the program, all GBA games need this as it sets up the interrupts and jumps to the main function
etc_bmp	.h	Include file that just exports pointers to each of the bmp images
gdbrc	N/A	Configuration for the GNU debugger for debugging the game
isle_bmp	.h	Include file for declaring pointers to every image of the rotating island sprite
ldscript	.x	Ld script that tells the Linker where to place data in the resulting ELF
menu	.c, .o
menu_bmp	.h	Include file for declaring pointers to every image of the menu
menu_dat	.c, .h, .o
oam_proc	.c, .h, .o
reverbpatch	.o
rom_header	.s	Assembly code that implements the common GBA ROM reader required of all GBA ROMs
soundpatch	.o
yos_anm	.c, .h, .o
yos_bmp	.h	Include file for declaring pointers to every image of the main game sprites
yos_game	.c, .ext, .h, .o
yos_game_dat	.c, .h, .o
yos_game_mov	.c, .h, .o
yos_game_pr	.c, .h, .o
yos_game_sub	.c, .h, .o
yos_main	.c, .ext, .h, .o
yos_main_dat	.c, .h, .o	Just contains pre-generated sin/cos tables
yos_sound	.h	Include file for declaring a few preprocessor macros used for sound effects
yos_type	.h	Include file for declaring a few custom coordinate types such as xyPos_tag
yoshi	.bin, .elf, .map	The main game executable in ELF format and the converted GBA rom file (.bin) along with the symbol MAP which shows where the code is inside the game

It is worth reading the Readme.txt file in this directory, most of the time Readmes are not that interesting but in this case you would be worse off not reading it. It provides an excellent overview of what the demo is showcasing and how it all works.

Code Files

bg_proc.c

short[256] tsin
short[256] tcos
u8[4096] Bg1_ScreenDat
u16[1024] Bg2_ScreenDat
u16[1024] Bg3_ScreenDat
u8 Bg_Mode
s32 prev_x
s32 prev_y
BgDat Bg1
BgDat Bg2
BgDat Bg3
s32 rot_center_x
s32 rot_center_y
vs32 bg2pa
vs32 bg2pb
vs32 bg2pc
vs32 bg2pd
vs32 bg2_center_x
vs32 bg2_center_y
vu32 scale_x
vu32 scale_y
vu16 rotate_value
int move_val_x
int move_val_y
float Bg1_Offset_X
float Bg1_Offset_Y
float Bg3_Offset_Y
int Counter
u8 Biyoon_Count
s32 Sa
int tileX
int tileY
int MapX
int MapY
int SoundSize
void bg_init(s8)
void bg_init_first()
void bg_init_gameover()
void bg_init_dead()
void bg_modified(s32,s32,s32)
void Bgmode1(s32,s32,s32)
void siro_anm(s16)
void Bgmode3()
void Bg2_UpDown(s32)
void SetBgTextControl(vu16*,u16,u16,u16,u16,u16,u16)
void SetBgRotationControl(vu16*,u16,u16,u16,u16,u16,u16,u16)
void SetDispControl(vu16*,u16,u16,u16,u16,u16,u16,u16,u16,u16,u16,u16,u16,u16)
void InitBg1()
u8 InitBg1_Map(u8,u8)
void BgUpdate(s32,s32,s32)
void RightBg1()
void LeftBg1()
void InitBg2()
u16 InitBg2_Map(u8,u8)
void RightBg2()
void LeftBg2()
void InitBg3()
u16 InitBg3_Map(u8,u8)
void RightBg3()
void LeftBg3()

990

menu_dat.c

u16 const[256] p0_yoshi_island_Palette
u8 const*[60] p0_isle_tbl
u8 const[60] p0_size_tbl
u8 const*[60] p0_map_tbl

183

menu.c

s16 p0_isle_frm
s16 p0_count
s16[228] p0_h_org_b
s16[228] p0_h_tmp_b
s16[256][4] p0_h_bg2p
u8[1024] p0_BgBak
s32 p0_hsy_org
void p0_set_umi_sora()
void proc_0()
void p0_VIntrFunc()
void p0_VCountIntr()

390

oam_proc.c

s8[10] OamList
u8 oamNode_end
u8 oamWaitFlg
OamListNode[128] OamNode
AffineParamWork[32] affineWork
DmaReqDat[64] dmaReqArray
u16 dmaReqNum
AnmWork[64] anmWork
void make_OamBuf()
void clear_OamList()
void add_OamList(u8,s8)
OamData* new_OamData(u8)
void dmaReqSet(u8*,u16,u16)

111

yos_anm.c

u8 const*[] p1_yoshi_pixel_tbl
AnmTbl const[3] yoshi_anm_normal
AnmTbl const[16] yoshi_anm_walk
AnmTbl const[16] yoshi_anm_run
AnmTbl const[9] yoshi_anm_l2r
AnmTbl const[16] yoshi_anm_jump
AnmTbl const[65] yoshi_anm_kyoro
AnmTbl const[16] yoshi_anm_tyouhatu
AnmTbl const[16] yoshi_anm_funbari
AnmTbl const[2] yoshi_anm_kururinha
AnmTbl const[40] yoshi_anm_die
AnmTbl const[9] yoshi_anm_bring1
AnmTbl const[16] yoshi_anm_bring2
AnmTbl const*[12] p1_yoshi_anm_patern
AnmTbl const[9] hei_anm_walk
AnmTbl const[5] hei_anm_turn
u8 const*[] p1_heiho_pixel_tbl
u8 const*[] p1_heiho_b_pixel_tbl
u8 const*[] p1_heiho_g_pixel_tbl
u8 const*[] p1_heiho_y_pixel_tbl
u8 const*[] p1_heihoL_pixel_tbl
AnmTbl const*[3] p1_heiho_anm_patern
AnmTbl const[3] mbox_anm_normal
u8 const*[] p1_mbox_pixel_tbl
AnmTbl const*[2] p1_mbox_anm_patern
AnmTbl const[4] sun_anm_d
AnmTbl const[4] sun_anm_c
AnmTbl const[4] sun_anm_normal
AnmTbl const[4] sun_anm_s
AnmTbl const[4] sun_anm_sp
u8 const*[] p1_sun_pixel_tbl
AnmTbl const*[6] p1_sun_anm_patern
AnmTbl const[12] killerS_anm_normal
u8 const*[] p1_killerS_pixel_tbl
AnmTbl const*[2] p1_killerS_anm_patern
AnmTbl const[5] kokamek_anm_normal
AnmTbl const[5] kokamek_anm_ura
u8 const*[] p1_kokamek_pixel_tbl
AnmTbl const*[3] p1_kokamek_anm_patern
AnmTbl const[9] hosi_anm_normal
u8 const*[] p1_hosi_pixel_tbl
AnmTbl const*[2] p1_hosi_anm_patern
AnmTbl const[9] kurukemu_anm_normal
u8 const*[] p1_kurukemu_pixel_tbl
AnmTbl const*[2] p1_kurukemu_anm_patern
AnmTbl const[15] balloon_anm_normal
u8 const*[] p1_balloon_pixel_tbl
AnmTbl const*[2] p1_balloon_anm_patern
AnmTbl const[9] bomb_anm_normal
u8 const*[] p1_bomb_pixel_tbl
AnmTbl const*[2] p1_bomb_anm_patern

1082

yos_game_dat.c

CharMapData const[36] p1_charMapData
xyPos const[26] p1_mapALine
u32 const[1][2] p1_OamData_Sample
xyPos const p1_yoshi_start_pos
CharSpecData const[34] p1_charSpecData
ObjChr const[39] p1_objChrTbl
ObjChr const[4] p1_objChrTbl2
AnmInfo const[64] p1_anmInfo_def
xyPos const[8] p1_hanabira_pos
s16[8] p1_hanabira_rot_tbl
s32 const[10] p1_tatenobi_tbl
u16 const[256] p1_obj_Palette
xyPos const[4] p1_kokamekPos
s32 const[4][3] p1_koumoriDat
xyPos const[8] p1_balloon_randv_tbl
xyPos[1] p1_balloon_pos
u8**[4] p1_heiho_pix_tbl

350

yos_game_mov.c

s16[3] p1_egg_se_tbl
void p1_yoshi_init1()
void p1_jump_se_set()
void p1_yoshiMove()
void p1_yos_histry_set()
void p1_heiho_move(u8)
void p1_heihoL_move(u8)
void p1_killerS_move(u8)
void p1_balloon_move(u8)
void p1_omori_move(u8)
void p1_bomb_move(u8)
void p1_kokamek_move(u8)
void p1_toge_move(u8)
void p1_hakoMove(u8)
void p1_charMove()
void p1_hanabiraMove()
void p1_eggMove()
void p1_effectMove()

1885

yos_game_pr.c

void p1_yoshiPrint()
void p1_yoshiKagePrint()
void p1_eggPrint()
void p1_charPrint()
void p1_gagePrint()
void p1_heiKagePrint(xyPos,s8)
void p1_heiKagePrintL(xyPos)
void p1_bombKagePrint(xyPos)
void p1_effectPrint()
void p1_kokamekPrint()
void p1_kumoPrint()
void p1_koumoriPrint()

607

yos_game_sub.c

void p1_workInit0()
void p1_affineWorkInit0()
void p1_charWorkInit0()
s16 p1_yos_hit_yoko(xyPos,s16*)
s16 p1_yos_hit_tate(xyPos,s16*)
s8 p1_jimen_cross_chk_yoko(xyPos,xyPos)
s8 p1_jimen_cross_chk(xyPos,xyPos)
s8 p1_line_cross_chk_tate(xyPos,xyPos,xyPos,xyPos)
u32 p1_getMap(long)
s8 p1_line_cross_chk_yoko(xyPos,xyPos,xyPos,xyPos)
s32 p1_get_rel_pos(s32)
s32 p1_get_lap_pos(s32)
void p1_yoshi_dead_set()
void p1_yoshi_jump_set(s32)
void p1_effectSet(s8,xyPos,xyPos*)
void p1_balloon_dead(s16)
void p1_anim_work_proc()
s8 p1_turekomi_fly_pos_set(s32)
void p1_clear_anm()
void p1_key_chk()
void p1_calcDispPosition()

962

yos_game.c

gGames p1_gGame
u8 p1_sub_status
s32 p1_line_count
YoshiWork p1_yoshiWork
EffectWork[32] p1_effWork
CharacterWork[3] p1_eggWork
CharacterWork[4] p1_kokamekWork
CharacterWork[8] p1_hanabiraWork
CharacterWork[48] p1_charWork
func_ptr const[4] func_tbl
void yos_game()
void VIntrFunc()
void game_init0()
void game_init1()
void game_main()
void game_over0()

487

yos_main_dat.c

s16 const[256] fix_sin
s16 const[256] fix_cos

yos_main.c

gMainVal gMain
IntrFuncp[15] IntrTable
IntrFuncp const[14] IntrTable_0
void(*[2])() proc_func_tbl
void AgbMain()
void IntrDummy()
void VBlankIntr()
void KeyRead()

165

BMP images (yoshi/bmp/*)

This folder contains images used in the game in bmp format and the compiled versions in .c and .o formats (created with bmp2map).

File Name	Extension	Description
*/Makefile	N/A	Makefile to convert .bmp files into .o files by running bmp2map
*/bmpfiles	N/A	List of all the BMP files to convert (read from the Makefile)
islebmp/libislebmp	.a	Static Library archive of all the island animation images
islebmp/yoshi_island_9909070(1-60)	.bmp, .o	Each image is a frame in an animation of the island spinning around
menubmp/grade	.bmp, .o	Gradient image used for the menu
menubmp/kumo	.bmp, .o	Static-like texture used for the menu
menubmp/libmenubmp	.a	Static Library archive of all the menu images
menubmp/umi64	.bmp, .o	Water image used for the menu
yosbgbmp/bg1	.bmp, .c, .o, .plb	The background image used for the platforms/path that Yoshi walks on
yosbgbmp/bg2	.bmp, .c, .o	The background image used for the hills in the background
yosbgbmp/bg2_5	.bmp	The background image used for the hills in the background but with a texture applied to it
yosbgbmp/bg3	.bmp, .c, .o	The background image used for the Sky (says made in japan on it)
yosbgbmp/libyosbgbmp	.a	Static Library archive of all the background images used in the level
yosbgbmp/tmp	.bmp	I think this is a tileset image?

What is the bg1.plb file and what is it used for? Possibly collision detection?

Yosbmp (yoshi/bmp/yosbmp)

This folder contains sprites used in the Yoshi level including all the animation frames.

This folder contains .imb files which are the result of calling bmp2bin on the BMP images and .o files which are the result of calling objcopy on the same images.

File Name	Extension	Description
CCCC_A	.bmp, .imb, .o
CCCC_B	.bmp, .imb, .o
CCCC_C	.bmp, .imb, .o
DDDD_A	.bmp, .imb, .o
DDDD_B	.bmp, .imb, .o
DDDD_C	.bmp, .imb, .o
HANABIRA1	.bmp, .imb, .o
HANABIRA2	.bmp, .imb, .o
HANABIRA3	.bmp, .imb, .o
HANABIRAn_1	.bmp, .imb, .o
HANABIRAn_2	.bmp, .imb, .o
HANABIRAn_3	.bmp, .imb, .o
HANABIRAy_1	.bmp, .imb, .o
HANABIRAy_2	.bmp, .imb, .o
HANABIRAy_3	.bmp, .imb, .o
HEIHO929_001	.bmp, .imb, .o
HEIHO929_001_b	.bmp, .imb, .o
HEIHO929_001_g	.bmp, .imb, .o
HEIHO929_001_y	.bmp, .imb, .o
HEIHO929_003	.bmp, .imb, .o
HEIHO929_003_b	.bmp, .imb, .o
HEIHO929_003_g	.bmp, .imb, .o
HEIHO929_003_y	.bmp, .imb, .o
HEIHO929_005	.bmp, .imb, .o
HEIHO929_005_b	.bmp, .imb, .o
HEIHO929_005_g	.bmp, .imb, .o
HEIHO929_005_y	.bmp, .imb, .o
HEIHO929_007	.bmp, .imb, .o
HEIHO929_007_b	.bmp, .imb, .o
HEIHO929_007_g	.bmp, .imb, .o
HEIHO929_007_y	.bmp, .imb, .o
HEIHO929_009	.bmp, .imb, .o
HEIHO929_009_b	.bmp, .imb, .o
HEIHO929_009_g	.bmp, .imb, .o
HEIHO929_009_y	.bmp, .imb, .o
HEIHO929_011	.bmp, .imb, .o
HEIHO929_011_b	.bmp, .imb, .o
HEIHO929_011_g	.bmp, .imb, .o
HEIHO929_011_y	.bmp, .imb, .o
HEIHO929_013	.bmp, .imb, .o
HEIHO929_013_b	.bmp, .imb, .o
HEIHO929_013_g	.bmp, .imb, .o
HEIHO929_013_y	.bmp, .imb, .o
HEIHO929_015	.bmp, .imb, .o
HEIHO929_015_b	.bmp, .imb, .o
HEIHO929_015_g	.bmp, .imb, .o
HEIHO929_015_y	.bmp, .imb, .o
HEIHO_l_001	.bmp, .imb, .o
HEIHO_l_003	.bmp, .imb, .o
HEIHO_l_005	.bmp, .imb, .o
HEIHO_l_007	.bmp, .imb, .o
HEIHO_l_009	.bmp, .imb, .o
HEIHO_l_011	.bmp, .imb, .o
HEIHO_l_013	.bmp, .imb, .o
HEIHO_l_015	.bmp, .imb, .o
HEIHO_l_turn_002	.bmp, .imb, .o
HEIHO_l_turn_003	.bmp, .imb, .o
HEIHO_normal_walk_turn_002	.bmp, .imb, .o
HEIHO_normal_walk_turn_002_b	.bmp, .imb, .o
HEIHO_normal_walk_turn_002_g	.bmp, .imb, .o
HEIHO_normal_walk_turn_002_y	.bmp, .imb, .o
HEIHO_normal_walk_turn_003	.bmp, .imb, .o
HEIHO_normal_walk_turn_003_b	.bmp, .imb, .o
HEIHO_normal_walk_turn_003_g	.bmp, .imb, .o
HEIHO_normal_walk_turn_003_y	.bmp, .imb, .o
Makefile	N/A
NNNN_A	.bmp, .imb, .o
NNNN_B	.bmp, .o
NNNN_C	.bmp, .o
PS_MEPACHI_B2	.bmp, .o
PS_MEPACHI_B3	.bmp, .o
PS_MEPACHI_B4	.bmp, .o
PS_MEPACHI_B5	.bmp, .o
PS_MEPACHI_B6	.bmp, .o
PS_MEPACHI_M2	.bmp, .o
PS_MEPACHI_M3	.bmp, .o
PS_MEPACHI_M4	.bmp, .o
PS_MEPACHI_M5	.bmp, .o
PS_MEPACHI_M6	.bmp, .o
PS_MEPACHI_Y2	.bmp, .o
PS_MEPACHI_Y3	.bmp, .o
PS_MEPACHI_Y4	.bmp, .o
PS_MEPACHI_Y5	.bmp, .o
PS_MEPACHI_Y6	.bmp, .o
PS_U_turn1	.bmp, .o
PS_U_turn2	.bmp, .o
PS_U_turn3	.bmp, .o
PS_U_turn4	.bmp, .o
PS_U_turn5	.bmp, .o
PS_U_turn6	.bmp, .o
PS_U_turn7	.bmp, .o
PS_U_turn8	.bmp, .o
PS_hey1	.bmp, .o
PS_hey2	.bmp, .o
PS_hey3	.bmp, .o
PS_hey4	.bmp, .o
PS_hey5	.bmp, .o
PS_hey6	.bmp, .o
PS_hey7	.bmp, .o
PS_hey8	.bmp, .o
PS_jump1	.bmp, .o
PS_jump2	.bmp, .o
PS_jump3	.bmp, .o
PS_jump4	.bmp, .o
PS_jump5	.bmp, .o
PS_jump6	.bmp, .o
PS_jump7	.bmp, .o
PS_jump8	.bmp, .o
PS_kihon_M	.bmp, .o
PS_kihon_Y	.bmp, .o
PS_kyoro_B	.bmp, .o
PS_kyoro_B10	.bmp, .o
PS_kyoro_B11	.bmp, .o
PS_kyoro_B2	.bmp, .o
PS_kyoro_B3	.bmp, .o
PS_kyoro_B4	.bmp, .o
PS_kyoro_B5	.bmp, .o
PS_kyoro_B6	.bmp, .o
PS_kyoro_B7	.bmp, .o
PS_kyoro_B8	.bmp, .o
PS_kyoro_B9	.bmp, .o
PS_kyoro_M10	.bmp, .o
PS_kyoro_M11	.bmp, .o
PS_kyoro_M2	.bmp, .o
PS_kyoro_M3	.bmp, .o
PS_kyoro_M4	.bmp, .o
PS_kyoro_M5	.bmp, .o
PS_kyoro_M6	.bmp, .o
PS_kyoro_M7	.bmp, .o
PS_kyoro_M8	.bmp, .o
PS_kyoro_M9	.bmp, .o
PS_kyoro_Y10	.bmp, .o
PS_kyoro_Y11	.bmp, .o
PS_kyoro_Y2	.bmp, .o
PS_kyoro_Y3	.bmp, .o
PS_kyoro_Y4	.bmp, .o
PS_kyoro_Y5	.bmp, .o
PS_kyoro_Y6	.bmp, .o
PS_kyoro_Y7	.bmp, .o
PS_kyoro_Y8	.bmp, .o
PS_kyoro_Y9	.bmp, .o
PS_kyoro_YR10	.bmp, .o
PS_kyoro_YR11	.bmp, .o
PS_kyoro_YR2	.bmp, .o
PS_kyoro_YR3	.bmp, .o
PS_kyoro_YR4	.bmp, .o
PS_kyoro_YR5	.bmp, .o
PS_kyoro_YR6	.bmp, .o
PS_kyoro_YR7	.bmp, .o
PS_kyoro_YR8	.bmp, .o
PS_kyoro_YR9	.bmp, .o
PS_turn1	.bmp, .o
PS_turn2	.bmp, .o
PS_turn3	.bmp, .o
PS_turn4	.bmp, .o
PS_turn5	.bmp, .o
PS_turn6	.bmp, .o
PS_turn7	.bmp, .o
PS_turn_L1	.bmp, .o
PS_turn_L2	.bmp, .o
PS_turn_L3	.bmp, .o
PS_turn_L4	.bmp, .o
PS_turn_L5	.bmp, .o
PS_turn_L6	.bmp, .o
PS_turn_L7	.bmp, .o
PS_turn_back1	.bmp, .o
PS_turn_back2	.bmp, .o
PS_turn_back3	.bmp, .o
PS_turn_back4	.bmp, .o
PS_turn_back5	.bmp, .o
PS_turn_back6	.bmp, .o
PS_turn_back7	.bmp, .o
PS_turn_mae1	.bmp, .o
PS_turn_mae2	.bmp, .o
PS_turn_mae3	.bmp, .o
PS_turn_mae4	.bmp, .o
PS_turn_mae5	.bmp, .o
PS_turn_mae6	.bmp, .o
PS_turn_mae7	.bmp, .o
PS_walk_B1	.bmp, .o
PS_walk_B10	.bmp, .o
PS_walk_B11	.bmp, .o
PS_walk_B12	.bmp, .o
PS_walk_B13	.bmp, .o
PS_walk_B14	.bmp, .o
PS_walk_B15	.bmp, .o
PS_walk_B16	.bmp, .o
PS_walk_B2	.bmp, .o
PS_walk_B3	.bmp, .o
PS_walk_B4	.bmp, .o
PS_walk_B5	.bmp, .o
PS_walk_B6	.bmp, .o
PS_walk_B7	.bmp, .o
PS_walk_B8	.bmp, .o
PS_walk_B9	.bmp, .o
PS_walk_M1	.bmp, .o
PS_walk_M10	.bmp, .o
PS_walk_M11	.bmp, .o
PS_walk_M12	.bmp, .o
PS_walk_M13	.bmp, .o
PS_walk_M14	.bmp, .o
PS_walk_M15	.bmp, .o
PS_walk_M16	.bmp, .o
PS_walk_M2	.bmp, .o
PS_walk_M3	.bmp, .o
PS_walk_M4	.bmp, .o
PS_walk_M5	.bmp, .o
PS_walk_M6	.bmp, .o
PS_walk_M7	.bmp, .o
PS_walk_M8	.bmp, .o
PS_walk_M9	.bmp, .o
PS_walk_Y1	.bmp, .o
PS_walk_Y10	.bmp, .o
PS_walk_Y11	.bmp, .o
PS_walk_Y12	.bmp, .o
PS_walk_Y13	.bmp, .o
PS_walk_Y14	.bmp, .o
PS_walk_Y15	.bmp, .o
PS_walk_Y16	.bmp, .o
PS_walk_Y2	.bmp, .o
PS_walk_Y3	.bmp, .o
PS_walk_Y4	.bmp, .o
PS_walk_Y5	.bmp, .o
PS_walk_Y6	.bmp, .o
PS_walk_Y7	.bmp, .o
PS_walk_Y8	.bmp, .o
PS_walk_Y9	.bmp, .o
SSSS_A	.bmp, .o
SSSS_B	.bmp, .o
SSSS_C	.bmp, .o
balloon	.bmp, .o
balloon01	.bmp, .o
balloon02	.bmp, .o
balloon03	.bmp, .o
balloon04	.bmp, .o
balloon05	.bmp, .o
balloon06	.bmp, .o
balloon07	.bmp, .o
balloon08	.bmp, .o
balloon09	.bmp, .o
balloon10	.bmp, .o
balloon11	.bmp, .o
balloon12	.bmp, .o
balloon13	.bmp, .o
batabata1	.bmp, .o
batabata2	.bmp, .o
batabata3	.bmp, .o
batabata4	.bmp, .o
batabata5	.bmp, .o
batabata6	.bmp, .o
batabata7	.bmp, .o
batabata8	.bmp, .o
bmpfiles	N/A
bomb_1	.bmp, .o
bomb_2	.bmp, .o
bomb_3	.bmp, .o
bomb_4	.bmp, .o
bomb_5	.bmp, .o
casle1	.bmp, .o
casle1p	.bmp, .o
casle3	.bmp, .o
casle3p	.bmp, .o
casle4	.bmp, .o
casle4p	.bmp, .o
casle5	.bmp, .o
casle5p	.bmp, .o
casle6	.bmp, .o
casle6p	.bmp, .o
casle7	.bmp, .o
casle7p	.bmp, .o
dokan	.bmp, .o
egg	.bmp, .o
hana	.bmp, .o
hosi1	.bmp, .o
hosi2	.bmp, .o
hosi3	.bmp, .o
hosi4	.bmp, .o
hosi5	.bmp, .o
hosi6	.bmp, .o
hosi7	.bmp, .o
hosi8	.bmp, .o
kage0	.bmp, .o
kagel	.bmp, .o
killer_l1	.bmp, .o
killer_l2	.bmp, .o
killer_l3	.bmp, .o
killer_lA	.bmp, .o
killer_lAA	.bmp, .o
killer_lB	.bmp, .o
killer_lC	.bmp, .o
killer_lD	.bmp, .o
killer_lE	.bmp, .o
killer_s1	.bmp, .o
killer_s2	.bmp, .o
killer_s3	.bmp, .o
killer_sA	.bmp, .o
killer_sAA	.bmp, .o
killer_sB	.bmp, .o
killer_sC	.bmp, .o
killer_sD	.bmp, .o
killer_sE	.bmp, .o
kokamek_a	.bmp, .o
kokamek_c	.bmp, .o
kokamek_d	.bmp, .o
kokamek_e	.bmp, .o
koumori	.bmp, .o
kuki	.bmp, .o
kumo_nuki_l	.bmp, .o
kumo_nuki_r	.bmp, .o
kururi1	.bmp, .o
kururi2	.bmp, .o
kururi3	.bmp, .o
kururi4	.bmp, .o
kururi5	.bmp, .o
kururi6	.bmp, .o
kururi7	.bmp, .o
kururi8	.bmp, .o
libyosbmp	.a
mBOX1	.bmp, .o
mBOX2	.bmp, .o
omori5t	.bmp, .o
sPPPP_A	.bmp, .o
sPPPP_B	.bmp, .o
sPPPP_C	.bmp, .o
toge	.bmp, .o

Sound (yoshi/sound)

Just as the name might imply this folder contains the sounds used in the demo, it is using a GBA Sound library library called m4alib which you can find out more about in our other post.

M4A Music Library for Game Boy Advance (GBA)

For more information about the M4A Sound library check out this post.

This folder only contains the pre-compiled object files, presumably these have been converted from a sound format and compiled into these for easy linking with the rest of the game.

Sadly the original sound files don’t seem to exist.

File Name	Extension	Description
SoundDat	.o
Soundfiles	N/A	List of all sound object files to link to the game, used by the Makefile
bm_atri	.o
c_gaonn	.o
e_derup	.o
e_onpp1	.o
e_torup	.o
ht_atar	.o
ht_ware	.o
i_b_sx	.o
i_bell	.o
i_bscl	.o
i_drm1	.o
i_drm2	.o
i_elsn	.o
i_mari	.o
i_strg	.o
i_timp	.o
i_vb_t	.o
i_vibe	.o
ki_sid2	.o
km_ukuu	.o
m4aLib	.h, .o
m5t_dsin	.o
mc_gaonn	.o
me_derup	.o
me_onpp1	.o
me_onpp2	.o
me_onpp3	.o
me_torup	.o
mh_kaitn	.o
mht_apir	.o
mht_atar	.o
mht_ware	.o
mki_sid1	.o
mki_sid2	.o
mkm_ukuu	.o
mm_1game	.o
mm_gover	.o
mm_title	.o
mov_arra	.o
mtg_raka	.o
mtp_stat	.o
my_dmgn1	.o
my_dmgn2	.o
my_dwnau	.o
my_hipha	.o
my_hipkr	.o
my_jmpfm	.o
my_jmph1	.o
my_jmpst	.o
my_jmpy1	.o
my_pakon	.o
my_stph1	.o
my_stpn1	.o
my_tont1	.o
my_tont2	.o
my_upup	.o
ov_arra	.o
ov_basa	.o
ov_hkob	.o
ov_konn	.o
ov_shaa	.o
ov_sir2	.o
t5_dsin	.o
t5_undr	.o
tg_raka	.o
y_dmgn1	.o
y_dmgn2	.o
y_dwnau	.o
y_hipha	.o
y_hipkr	.o
y_jmpfm	.o
y_jmph1	.o
y_jmpst	.o
y_jmpy1	.o
y_pakon	.o
y_runtn	.o
y_stph1	.o
y_stpn1	.o
y_stpqu	.o
y_tont1	.o
y_tont2	.o
y_upup	.o
y_ywiha	.o

Zelda 2 Tech demo

A long-rumored Zelda II tech demo for GBA has finally surfaced, ROM and source code included!

It's a included as reference in the GBA SDK, found on a Spongebob GBA dev disc uploaded by @JacobLenstar.

ROM + Source:https://t.co/p9aCkSF8Q1

Full archive:https://t.co/7hquBy9lnX pic.twitter.com/mrvtbkudJ8
— MrTalida (@MrTalida) December 22, 2019