QWEN Instructions

Qwen has 26 instructions. Instructions are all two bytes long and stored big-endian. The instructions are listed below, in hexadecimal.
Symbols:
-NNNN: Address
-NN: 8-bit constant
-N: 4-bit constant
-X and Y: 4-bit register identifier
-PC: Program Counter
-I: 16-bit register
-RN: One of the 16 variables. N can be 0 to F (Hexadecimal)

Opcode	Type	C Pseudo	Explanation
0x0000	Display	clear();	Clears the display.
0x0001	Flow	return;	Returns from a subroutine. Sets the PC to address at the top of the stack, then subtracts 1 from the stack pointer (SP).
0x0002	Flow	goto NNNN;	Jumps to address NNNN(High byte from R0 register and low byte from R1 register). Sets the PC to NNNN.
0x0003	Flow	*(0xNNNN)();	Calls subroutine at NNNN(High byte from R0 register and low byte from R1 register). Increments the stack pointer, then puts the current PC on the top of the stack. The PC is then set to NNNN.
0x1XNN	Assign	RX = NN;	Sets RX to NN.
0x2XY0	Assign	RX = RY;	Sets RX to the value of RY.
0x2NN1	Assign	*((R0<<8) | (R1)) = NN;	Set (R0<<8) | R1 memory location to NN.
0x31XY	Bitwise Operation	RX = RX | RY;	Sets RX to RX or RY (Bitwise OR Operation).
0x32XY	Bitwise Operation	RX = RX & RY;	Sets RX to RX and RY (Bitwise AND Operation).
0x33XY	Bitwise Operation	RX = RX ^ RY;	Sets RX to RX xor RY (Bitwise XOR Operation).
0x34X1	Bitwise Operation	RX >>= 1;	Stores the least significant bit of RX in RF and then shifts RX to the right by 1.
0x34X2	Bitwise Operation	RX <<= 1;	Stores the most significant bit of RX in RY and then shifts RX to the left by 1.
0x4XNN	Math Operation	RX += NN;	Adds NN to RX (Carry flag is not changed).
0x51XY	Math Operation	RX += RY;	Adds RY to RX. RF is set to 1 when there's carry, and to 0 when there isn't.
0x52XY	Math Operation	RX -= RY;	RY is subtracted from RX. RF is set to 0 when there's a borrow, and 1 when there isn't.
0x6XNN	Condition	if (RX==NN);	Skip the next instruction if RX equals NN.
0x7XNN	Condition	if (RX!=NN);	Skip the next instruction if RX doesn't equal NN.
0x8XY0	Condition	if (RX==RY);	Skip the next instruction if RX qeuals RY.
0x9X01	Key Operation	if (key()==RX);	Skip the next instruction if the key stored in RX is pressed .
0xA000	Memory	RI += NNNN;	Adds NNNN(High byte from R0 register and low byte from R1 register) to RI
0xBX00	Memory	RI = sprite_address[RX];	Sets RI to the location of the sprite for the character code in RX. Characters A-Z (Non-case-sensitive), 0-9, +, -, *, /.
0xC00X	Random Operation	RX = rand();	Sets RX to a random number(0-255).
0xDXY0	Display	Draw(RX,RY);	Draw a sprite at coordinate(RX, RY) that has a 8x8 pixels. Each row of 8 pixels is read as 4-bit-coded starting from memory location RI.
0xEX00	Key Operation	RX = get_key();	A key press is awaited, and then stored in RX.
0xFNN0	Timer	delay(NN);	Delay NN milliseconds.
0xF0N1	Sound	play_sound(N);	Play sound N(see sound chart) for 0.5 milliseconds.