Emma 02

aaa	12 bit address
kk	8 bit constant
n	4 bit constant
x	Register number Vx (x = 0 to F)
y	Register number Vy (y = 0 to F)
I	Register I (12 bit)
[I]	Memory value of address in register I
NH	Bit 0-3 Horizontal Location Bit 4-7, Horizontal width
NV	Bit 0-3 Vertical Location Bit 4-7, Vertical height
1..9, A..F	Hexadecimal digits

Opcode	Mnemonic	Parameter	Definition
Fx1E	ADD	I, Vx	I = I + Vx
7xkk	ADD	Vx, kk	Vx = Vx + kk
8xy4	ADD	Vx, Vy	Vx = Vx + Vy, VF = carry
8xy2	AND	Vx, Vy	Vx = Vx AND Vy, VF undefined
2aaa	CALL	aaa	Call subroutine at aaa (16 levels)
00E0	CLS		Clear display
Dxyn	DRW	Vx, Vy, n	Draw n byte sprite stored at [I] at Vx, Vy. Set VF = collision
1aaa	JP	aaa	Jump to address aaa
Baaa	JP	V0, aaa	Jump to address aaa + V0
Fx33	LD	B, Vx	Store BCD value of Vx in [I], [I+1], [I+2]
Fx15	LD	DT, Vx	Delaytimer = Vx
Fx29	LD	F, Vx	Point I to 5 byte numeric sprite for value in Vx
Aaaa	LD	I, aaa	I = aaa
Fx18	LD	ST, Vx	Soundtimer = Vx
Fx07	LD	Vx, DT	Vx = Delaytimer
Fx0A	LD	Vx, K	Vx = key, wait for keypress
6xkk	LD	Vx, kk	Vx = kk
8xy0	LD	Vx, Vy	Vx = Vy, VF undefined
Fx65	LD	Vx, [I]	Read V0 .. Vx from [I] .. [I+x]
Fx55	LD	[I], Vx	Store V0 .. Vx in [I] .. [I+x]
8xy1	OR	Vx, Vy	Vx = Vx OR Vy, VF undefined
00EE	RETURN		Return from subroutine (16 levels)
Cxkk	RND	Vx , kk	Vx = random AND kk
3xkk	SE	Vx , kk	Skip next instruction if Vx == kk
5xy0	SE	Vx , Vy	Skip next instruction if Vx == Vy
8xxE	SHL	Vx	Vx = Vx << 1, VF = carry
8xyE	SHL	Vx , Vy	Vx = Vy << 1, VF = carry
8xx6	SHR	Vx	Vx = Vx >> 1, VF = carry
8xy6	SHR	Vx , Vy	Vx = Vy >> 1, VF = carry
Ex9E	SKP	Vx	Skip next instruction if key Vx down
ExA1	SKNP	Vx	Skip next instruction if key Vx up
4xkk	SNE	Vx, kk	Skip next instruction if Vx != kk
9xy0	SNE	Vx, Vy	Skip next instruction if Vx != Vy
8xy5	SUB	Vx, Vy	Vx = Vx - Vy, VF = !borrow
8xy7	SUBN	Vx, Vy	Vx = Vy - Vx, VF = !borrow
0aaa	SYS	aaa	Call CDP1802 code at aaa
8xy3	XOR	Vx, Vy	Vx = Vx XOR Vy, VF undefined

All of the instruction from Chip-8, except 'Baaa: JP V0, aaa' are valid for Chip-8X. Chip-8X offers the following additional instructions:

Opcode	Mnemonic	Parameter	Definition
5xy1	ADD8	Vx, Vy	Vx = Vx + Vy (hex digits 00 to 77, mainly for manipulating the NH and NV parameters)
02A0	CLR	B BACK	Step background 1 colour (-> blue, -> black, -> green, -> red ->)
Bxy0	CLR CLRL	Vx, Vy Vx/Vz, Vy	Set Vy colour @ Vx (NH), Vz (Vz has to be V(x+1)) (NV)
Bxyn	CLR CLRH	Vx, Vy, n Vx/Vz, Vy, n	Set Vy colour @ Vx, Vz (Vz has to be V(x+1)) byte, n bytes vertically, n != 0
FxFB	INP1	Vx	Input port 1 to Vx (waits for EF4=1)
FxF8	OUT3	Vx	Vx to output port 3 (used for simple sound)
ExF2	SKP2	Vx	Skip next instruction if key Vx on keypad 2 is down
ExF5	SKNP2	Vx	Skip next instruction if key Vx on keypad 2 is up

All of the instruction from Chip-8 are valid for the TI-660 Chip-8 variant. ETI-660 Chip-8 offers the following additional instruction:

Opcode	Mnemonic	Parameter	Definition
0000	EXIT		Return to Monitor
00F8	TVON		Turn the screen on
00FC	TVOFF		Turn the screen off
00FF	NOP		Do nothing
Fx00	LD	P, Vx	Set the pitch (frequency) of the tone generator (beeper) to Vx

All of the instruction from Chip-8 are valid for the Elf Chip-8 variant and also offers the following additional instruction:

Opcode	Mnemonic	Parameter	Definition
Fx75	OUT4	Vx	OUT 4 with Vx

EMMA 02