Texas Instruments MSP50C6xx manual Classes and Opcode Definition

Instruction Classification

Table 4–12. Classes and Opcode Definition

Bit	16	15	14		13		12	11	10	9		8	7		6		5	4		3	2	1	0
Class 1a	0	0		C1a			~A~	next A			An				am					Rx		pm
Class 1b	0	1				C1b			s		An				am					Rx		pm
Class 2a	1	0	1		0			C2a			An							imm8
Class 2b	1	1	1		0		0	next A			An				C2b			0		0	1	A~	~A
Class 3	1	1	1		0		0	next A			An					C3					0	A~†	~A
Class 4a	1	1	1		1		0	C4a		R					am					Rx		pm
Class 4b	1	0	1		1		C4b		k4	k3		k2	k7		k6		k5			R		k1	k0
Class 4c	1	1	1		1		1	1	1	0		0	0		C4c					R		x	x
Class 4d	1	1	1		1		1	1	1	0		0	1		C4d					R		x	x
Class 5	1	1	0		1				C5						am					Rx		pm
Class 6a	1	1	0		0		C6a		port4						am					Rx		pm
Class 6b	1	1	1		0		1	1	s		An						port6					C6b	~A~
Class 7a	1	1	1		1		1	1	1	0		1						vector8
Class 7b	1	0	0		0		0	0	Not				cc							rx		pm
JMP *An	1	0	0		0		1	0	x		An		x		x		x	x		x	x	x	x
Class 7c	1	0	0		0		0	1	Not				cc					x		x	x	x	x
CALL *An	1	0	0		0		1	1	x		An		x		x		x	x		x	x	x	x
Class 8a	1	0	0		1		1	flg	n			C8a						flagadrs					g/r
Class 8b	1	0	0		1		0	flg	Not				cc							Rx		C8b	C8b
Class 9a	1	1	1		0		1	0	0		An		C9a				0			Rx		1	1
Class 9b	1	1	1		1		1	1	0		C9a								k
Class 9c	1	1	1		1		1	0	1		An		0	C9c			x				imm5
Class 9d	1	1	1		1		1	1	1	1		0			C9d					0	0	0	0
ENDLOOP n	1	1	1		1		1	1	1	1		0	0		0		0	1		0	0	0	n
NOP	1	1	1		1		1	1	1	1		1	1		1		1	1		1	1	1	1

† Meaning of this bit depends on what class 3 instruction is used.

4.4.1Class 1 Instructions: Memory and Accumulator Reference

This class of instructions controls execution between data memory and the accumulator block. In addition to the explicit opcode field that specifies an arithmetic operation, an eight-bit data memory addressing mode reference field (am, Rx, pm i.e., adrs field) controls the addressing of one input operand, and a 4-bit field (An and next A in class 1a) or 2-bit field (An in class 1b) selects an accumulator location as the other input operand. The results are written to the addressed accumulator location (or to the offset accumulator in class 1a if ~A bit = 1). In addition, each instruction can be treated as a single word length operation or as a string, depending on the string control encoded in the op code (s = 1 in class 1b and An = 11 binary in class 1a).

Assembly Language Instructions 4-25