PLASMA Byte Codes

The compact code representation comes through the use of opcodes closely matched to the PLASMA compiler.

TOS: Top Of Stack value

NOS: Next On Stack value (TOS-1)

OPCODE	Name	Description	Operation
$00-$1F	CN	Constant Nybble	OPCODE/2 ==> TOS
$20	MINUS_ONE	constant -1	-1 ==> TOS
$22	BREQ	Branch EQual	NOS == TOS ?? IP = IP + OFFSET
$24	BRNE	Branch Not Equal	NOS <> TOS ?? IP = IP + OFFSET
$26	LA	Load Address	ABSOLUTE ADDR ==> TOS
$28	LLA	Load Local Address	LOCAL ADDR ==> TOS
$2A	CB	Constant Byte	CONSTANT BYTE ==> TOS
$2C	CW	Constant Word	CONSTANT WORD ==> TOS
$2E	CS	Constant String	STRING ADDR ==> TOS
$30	DROP	DROP top value	TOS ==>
$32	DROP2	DROP top 2 values	NOS, TOS ==>
$34	DUP	DUPlicate top value	TOS ==> TOS
$36	DIVMOD	DIVide & MOD tos,nos	NOS / TOS ==> TOS, NOS % TOS ==> NOS
$38	ADDI	ADD Immediate byte	TOS + IMM8 ==> TOS
$3A	SUBI	SUB Immediate byte	TOS - IMM8 ==> TOS
$3C	ANDI	AND Immediate byte	TOS & IMM8 ==> TOS
$3E	ORI	OR Immediate byte	TOS \| IMM8 ==> TOS
$40	ISEQ	IS nos EQual tos	NOS == TOS ==> TOS
$42	ISNE	IS nos Not Equal to tos	NOS <> TOS ==> TOS
$44	ISGT	IS nos Greater Than tos	NOS > TOS ==> TOS
$46	ISLT	IS nos Less Than tos	NOS < TOS ==> TOS
$48	ISGE	IS nos Greater or Equal to tos	NOS >= TOS ==> TOS
$4A	ISLE	IS nos Less or Equal to tos	NOS <= TOS ==> TOS
$4C	BRFLS	BRanch FaLSe	TOS == 0 ?? IP = IP + OFFSET
$4E	BRTRU	BRanch TRUe	TOS <> 0 ?? IP = IP + OFFSET
$50	BRNCH	BRaNCH	IP = IP + OFFSET
$52	SEL	SELect cases	TOS == CASE ?? IP = IP + OFFSET (FOR ALL CASES)
$54	CALL	CALL address	PUSH(IP+2), IP = ADDRESS
$56	ICAL	Indirect CALl	PUSH(IP+2), IP = TOS
$58	ENTER	ENTER frame size, param count	FP = FP - FRAME SIZE, PARAMS ==> LOCALS
$5A	LEAVE	LEAVE frame size	FP = FP + FRAME SIZE, IP = PULL()
$5C	RET	RETurn	IP = PULL()
$5E	CFFB	Constant $FF Byte	CONSTANT BYTE + $FF00 ==> TOS
$60	LB	Load Byte	(TOS) ==> TOS
$62	LW	Load Word	(TOS) ==> TOS
$64	LLB	Load Local Byte	FP[LOCAL] ==> TOS
$66	LLW	Load Local Word	FP[LOCAL] ==> TOS
$68	LAB	Load Absolute Byte	MEM[ADDR] ==> TOS
$6A	LAW	Load Absolute Word	MEM[ADDR] ==> TOS
$6C	DLB	Duplicate to Local Byte	TOS ==> FP[LOCAL], TOS ==> TOS
$6E	DLW	Duplicate to Local Word	TOS ==> FP[LOCAL], TOS ==> TOS
$70	SB	Store Byte	NOS ==> (TOS)
$72	SW	Store Word	NOS ==> (TOS)
$74	SLB	Store Local Byte	TOS ==> FP[LOCAL]
$76	SLW	Store Local Word	TOS ==> FP[LOCAL]
$78	SAB	Store Absolute Byte	TOS ==> MEM[ADDR]
$7A	SAW	Store Absolute Word	TOS ==> MEM[ADDR]
$7C	DAB	Duplicate to Absolute Byte	TOS ==> MEM[ADDR], TOS ==> TOS
$7E	DAW	Duplicate to Absolute Word	TOS ==> MEM[ADDR], TOS ==> TOS
$80	NOT	logical NOT	!TOS ==> TOS
$82	ADD	ADD nos to tos	NOS + TOS ==> TOS
$84	SUB	SUBtract tos from nos	NOS - TOS ==> TOS
$86	MUL	MULtiply nos times tos	NOS * TOS ==> TOS
$88	DIV	DIVide nos by tos	NOS / TOS ==> TOS
$8A	MOD	MODulo nos by tos	NOS % TOS ==> TOS
$8C	INCR	INCRement tos	TOS + 1 ==> TOS
$8E	DECR	DECRement tos	TOS - 1 ==> TOS
$90	NEG	NEGate tos	-TOS ==> TOS
$92	COMP	COMPliment tos	~TOS ==> TOS
$94	AND	bitwise AND	NOS & TOS ==> TOS
$96	IOR	bitwise Inclusive OR	NOS \| TOS ==> TOS
$98	XOR	bitwise eXclusive OR	NOS ^ TOS ==> TOS
$9A	SHL	SHift Left	NOS << TOS ==> TOS
$9C	SHR	SHift Right	NOS >> TOS ==> TOS
$9E	IDXW	InDeX Word	TOS * 2 + NOS ==> TOS
$A0	BRGT	BRanch GReater than (FOR/NEXT)	TOS > NOS ?? IP = IP + OFFSET
$A2	BRLT	BRanch Less Than (FOR/NEXT)	TOS < NOS ?? IP = IP + OFFSET
$A4	INCBRLE	INCrement, BRanch Less Equal (FOR/NEXT)	TOS + 1 ==> TOS, TOS <= NOS ?? IP = IP + OFFSET
$A6	ADDBRLE	ADD, BRanch Less Equal (FOR/NEXT)	NOS + TOS ==> TOS, TOS <= NOS ?? IP = IP + OFFSET
$A8	DECBRGE	DECrement, BRanch Greater Equal (FOR/NEXT)	TOS - 1 ==> TOS, TOS >= NOS ?? IP = IP + OFFSET
$AA	SUBBRGE	SUBtract, BRanch GReater Equal (FOR/NEXT)	NOS = TOS ==> TOS, TOS >= NOS :: IP = IP + OFFSET
$AC	BRAND	BRanch AND (SHORT CIRCUIT)	TOS == 0 ?? IP = IP + OFFSET :: TOS ==> TOS
$AE	BROR	BRanch OR (SHORT CIRCUIT)	TOS <> 0 ?? IP = IP + OFFSET :: TOS ==> TOS
$B0	ADDLB	ADD Local Byte	TOS + FP[LOCAL] ==> TOS
$B2	ADDLW	ADD Local Word	TOS + FP[LOCAL] ==> TOS
$B4	ADDAB	ADD Absolute Byte	TOS + MEM[ADDR] ==> TOS
$B6	ADDAW	ADD Absolute Word	TOS + MEM[ADDR] ==> TOS
$B8	IDXLB	INDeX word by Local Byte	TOS + FP[LOCAL] * 2 ==> TOS
$BA	IDXLW	INDeX word by Local Word	TOS + FP[LOCAL] * 2 ==> TOS
$BC	IDXAB	INDeX word by Absolute Byte	TOS + MEM[ADDR] * 2 ==> TOS
$BE	IDXAW	INDeX word by Absolute Word	TOS + MEM[ADDR] * 2 ==> TOS
$C0	NATV	back to in-line NATiVe code	JUMP (IP)