Stack based 8-Bit processor

Peripherals

Connected to a bidirectional bus.

Instruction set

Operand Code	Instruction	Signature	Description
00000000	nop		Just do nothing for a cycle straight
00010000	int	interrupt	Interrupt code to call on PIA
00100000	jmp	label	Jump to label if last operation had non zero result
00110000	wfi	interrupt	Wait for interrupt. If interrupt is zero, wait for any
00000100	push	stack, rx	Push the rx value to the index stack
00010100	pop	stack, rx	Pop into the register rx from index stack
00001000	read	rdx	Read from PIA into the target register
00011000	write	rdx	Write to PIA the value of target register
00000010	not	rx	negates rx
00010010	par	rx	parity of rx
00100010	cnt	rx	count of set bits in rx
00110110	and	rx,r1	Store and of rx and r1 into rx
01000110	or	rx,r1	Store or of rx and r1 into rx
01010110	xor	rx,r1	Store xor of rx and r1 into rx
01100110	mov	rx,r1	overwrite rx with r1
01110110	sl	rx,r1	shift rx left by r1
10000110	sr	rx,r1	shift rx right by r1
00001010	add	rx,r1	Add r1 to rx
00011010	sub	rx,r1	Subtract r1 from rx
00001110	seq	rx,ry	Set if rx = ry
00011110	slt	rx,ry	Set if rx < ry
00101110	sltu	rx,ry	set if abs(rx) < abs(ry)

Instruction Types

From	To	Type
00000000	11111110	Base Instructions
00000001	11111111	Possible extension