snes-emu / gose Goto Github PK

TAX TAY TSX TXA TXS TXY TYA TYX instructions are left unimplemented. There are rather straight forward to write

What's the status of this project?

The CPU runs much slower than expected. data fetching is the major bottleneck.

BoolToUint16 should be used as a function (not as a hashmap)

Currently the APU is not emulated, all games hang at its initialization

STP and WAI aren't implemented for now, we need to think of how we want to dot this

opcode 6F is missing

Since the CPU is using little endian convention our functions should too.

For example:

func JoinUint16(HH uint8, LL uint8) uint16 {
	var ret uint16
	buf := bytes.NewBuffer([]byte{LL, HH})
	binary.Read(buf, binary.LittleEndian, &ret)
	return ret
}

Should be

func JoinUint16(LL uint8, HH uint8) uint16 {
	var ret uint16
	buf := bytes.NewBuffer([]byte{LL, HH})
	binary.Read(buf, binary.LittleEndian, &ret)
	return ret
}

Super Metroid loops on those instructions:

80/843C:	AD1242  	lda $4212
80/843F:	10FB    	bpl $843C

The $4212 register is the HVBJOY register:

https://github.com/snes-emu/gose/blob/cpu-registers/core/io_register.go#L171-L189

This may come from the fact that V-blank trigger is not implemented yet.