Texas Instruments MSP50C6xx manual Class 2 Instruction Encoding, Class 2a Instruction Description

Instruction Classification

constants. Long constants (16 bits) and long string constants differ in that ref- erences are made to constants in the second word of the two-word instruction word. References made to a single 16-bit integer constant are immediate. That is, the actual constant value follows the first word opcode in memory. For string constants, the second word reference to the constants is immediate-indirect which indicates that the second word is the address of the least significant word of the string constant. This definition allows all long string constants to be located in a table and permits the reference in the machine language listing to be consistent with those of shorter constants.

Table 4–16. Class 2 Instruction Encoding

Bit	16	15	14	13	12	11	10	9		8	7	6	5	4	3	2	1	0
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

Table 4–17. Class 2a Instruction Description

	C2a		Mnemonic	Description
0	0	0	ADDB An, imm8	Add an 8-bit positive constant to the accumulator and store the result in the
				accumulator. ALU status is modified.
0	0	1	MOVB An, imm8	Load an 8-bit positive constant into accumulator. ALU status is modified.
0	1	0	SUBB An, imm8	Subtract 8-bit positive constant from accumulator and store result
				accumulator. ALU status modified.
0	1	1	CMPB An, imm8	Modify ALU status with the result of 8-bit positive value subtracted from
				accumulator. Original accumulator value not modified.
1	0	0	ORB An, imm8	Logical OR 8-bit positive constant with accumulator and store result to
				accumulator. ALU status modified.
1	0	1	ANDB An, imm8	Logical AND 8-bit positive constant with accumulator. Store result to
				accumulator. ALU status modified.
1	1	0	XORB An, imm8	Logical XOR 8-bit positive constant with accumulator. Store result to
				accumulator. ALU status modified.
1	1	1	MOVB MR, imm8	Load 8-bit constant to Multiplier register (MR). Does not change UM mode in
				status register but will zero fill the top 8 bits in MR register. No change in status.

Assembly Language Instructions 4-29