Appendix A - Pico-Code Buffer

Pico-Code Instructions

Name	Op Code	Length	Description
DTX	0000	20	DAT = X; X is a signed 16-bit value
DTA	0001	20	DAT = 2 raised to the X-th power; X is a 16-bit value
DSH	0010	4	DAT = DAT >> 1
ACD	0011	4	ACC = ACC + DAT
ACZ	0100	4	ACC = 0
MOV	1000	12	REG X = REG Y; X,Y are 4-bit values
JMP	1001	20	PC = X; X is a 16-bit value
BRZ	1010	20	PC = X (if ACC = 0)
BRN	1011	20	PC = X (if ACC < 0)
JIN	1100	8	PC = REG Y; Y is a 4-bit value
TRD	1101	8	DAT[0] = Tape[REG Y] (read a bit from the tape)
TWR	1110	8	Tape[REG Y] = DAT[0] (write a bit to the tape)
RET	1111	4	Return or Halt

Note: the following code is in an early stage of development and is subject to change.

Micro	Addr.	Op	Data	Description
XOR	0008	ACZ		ACC = 0
	000C	TRD	0	DAT[0] = Tape[0]
	0010	ACD		ACC = ACC + DAT[0] = DAT[0]
	0014	BRZ	8048	IF ACC = 0 GOTO 8048
	0028	ACZ		ACC = 0
	002C	DTX	0000	DAT = 0
	0040	TWR	0	Tape[0] = 0
	0044	RET
	8048	DTX	0001	DAT = 1
	005C	TWR	0	Tape[0] = 1
	0060	JMP	0000	GOTO NXT

QUAD	0200	DTA	0010	DAT = 2^16
		ACZ
		ACD		ACC = 2^16
		MOV	1C	DAT = REG C
		ACD
		MOV	C0	REG C = REG C + 2^16
		MOV	2C
		DTX	4
		MOV	04
		DTX	1
		MOV	31	REG 3 = 1
	0220	TRD	2	DAT[0] = Tape[2]
		TWR	3	Tape[3] = DAT[0]
		DTX	1
		MOV	02
		ACD
		MOV	20	REG 2++
		MOV	03
		ACD
		MOV	30	REG 3++
		DTX	FFFF
		MOV	04
		ACD
		MOV	40	REG 4--
		BRZ	0000	IF ACC = 0 GOTO NXT
		JMP	0220

NXT	0000	DTA	0010	DAT = 2^16
		ACZ
		ACD		ACC = 2^16
		MOV	1C	DAT = REG C
		ACD
		MOV	C0	REG C = REG C + 2^16
		JMP	0100	GOTO DECO

DECO	0100	DTA	0014	DAT = 2^20
		ACZ
		ACD
		MOV	20	REG 2 = 2^20
		DTA	0004
		ACD		ACC = 2^20 + 16
		MOV	F0	Reg. F:11,1 = ACC
		DTX	0008
		MOV	61	REG 6 = 8
	8500	TRD	C	DAT[0] = Tape[C] = [10,0]
		ACZ
		ACD		ACC = DAT
		BRZ	9000	IF ACC = 0 GOTO 9000
		MOV	16	DAT = 8,4,2,1 – must init REG 6 = 8 ok
		MOV	91	REG 9 = DAT
		DSH		DAT >> 1
		MOV	61	REG 6 = 4,2,1,0
		MOV	06	ACC = REG 6
		BRZ	9100
		MOV	12
		DSH
		MOV	21	REG 2 >> 1 = 2^19,18,17,16
		MOV	02	ACC = REG 2
		MOV	1F	DAT = REG F
		ACD		ACC = REG F + REG 2
		MOV	F0	REG F = ACC
	9000	MOV	0C
		DTX	0001
		ACD		ACC++
		MOV	C0	REG C++
		JMP	8500
	9100	MOV	0F	do a JIN on 16 bits to left of Tape[F]…
		DTX	FFF0
		ACD		ACC = REG F – 16
		MOV	70	REG 7 = start of tape
		MOV	37	save start of op-code
		ACZ
		MOV	20	SUM = 0
		DTX	16
		MOV	61	REG 6 = 16
	9200	TRD	7	DAT[0] = Tape[7]
		MOV	91	REG 9 = curr bit
		MOV	12	REG 2 = SUM
		ACZ
		ACD
		ACD		ACC = 2*REG 2
		MOV	19	DAT = curr bit
		ACD		ACC = ACC + curr bit
		MOV	20	REG 2 = SUM
		MOV	06
		DTX	FFFF
		ACD		ACC = REG 6 – 1
		MOV	60	REG 6--
		BRZ	9300
		MOV	07
		DTX	1
		ACD
		MOV	70	REG 7++
		JMP	9200
	9300	MOV	73	restore REG 7 to col. 0
		DTX	FFFC
		MOV	0C
		ACD
		MOV	C0	REG C = REG C - 4; back to col. 0
		JIN	2	do the JIN