akatsuki105 / magia

magia is a toy GBA emulator written in golang.

Magia

Magia is GBA emulator written in golang.

Warning: This emulator is WIP, so many ROMs don't work correctly now.

 

 

Run

Please download latest binary from Release.

$ magia XXXX.gba

Build

# go1.16.x
$ make build
$ ./build/darwin-amd64/magia XXXX.gba

Key

keyboard	game pad
←	← button
↑	↑ button
↓	↓ button
→	→ button
X	A button
Z	B button
S	R button
A	L button
Enter	Start button
Backspace	Select button

ToDo

• Window
• GUI
• Serial communication
• GameBoy Compatibility
• Debug feature
• Fix some bugs

Game Compatibility List

Game Title	Compatibility
バトルネットワーク ロックマンエグゼ2	✅
バトルネットワーク ロックマンエグゼ3 BLACK	✅
ロックマンエグゼ4 トーナメント ブルームーン	✅
ロックマンエグゼ6 電脳獣グレイガ・電脳獣ファルザー	✅
ドラゴンクエストモンスターズ キャラバンハート	✅
MOTHER1+2	✅
ポケットモンスター ファイアレッド	✅

Accuracy

Test	Result
Memory tests	1102/1552
I/O read tests	21/123
Timing tests	--/1660
Timer count-up tests	326/936
Timer IRQ tests	0/90
Shifter tests	140/140
Carry tests	93/93
Multiply long tests	52/72
BIOS math tests	625/625
DMA tests	964/1256
Misc. edge case tests	5/10

References

• GBATEK
• gba_doc_ja
• gdkchan/gdkGBA
• mgba-emu/mgba

magia's Issues

Calling ebiten.NewImageFromImage every frame might be problematic in terms of performance

https://github.com/pokemium/mettaur/blob/ba03c6cdcc7fe8b56a15546d4b9376c58014c4d4/cmd/main.go#L141

Instead, I recommend

1. creating an offscreen image
2. rendering the result onto the offscreen image by ReplacePixels.

Thanks!

low fps

games dont go above 15 fps is the internally set limit or hardware limitation ?

In both _armSTM() and _armLDM() functions, the handling of the writeBack variable is incorrect.

I have reviewed the issue you pointed out concerning the writeBack mechanism in the title:_armSTM() and _armLDM() functions. Here's a proper analysis and the proposed solution.

In both the title:_armSTM() and _armLDM() functions, the handling of the writeBack variable is incorrect.

The current code updates the value of register rn when the writeBack flag is not set, which is contrary to the expected behavior. The update should occur when the writeBack flag is set.

Suggested Fix
Modify the code so that the update g.R[rn] = rnval only happens if the writeBack flag is set.
Apply the same logic correction to the _armLDM() function as well.

// Correction inside _armSTM()
writeBack := util.Bit(inst, 21)
if writeBack {
	g.R[rn] = rnval
}

// Correction inside _armLDM() (Assuming similar logic applies)
writeBack := util.Bit(inst, 21)
if writeBack {
	g.R[rn] = rnval
}

This correction ensures that the writeBack flag is handled correctly, aligning the function's behavior with the expected theoretical operation. If similar issues are found elsewhere in the code, I recommend applying the same fix.