Texas Instruments MSP50C6xx manual Class 2b Instruction Description, C2b Mnemonic Description

Instruction Classification

Table 4–18. Class 2b Instruction Description

	C2b			Mnemonic	Description
0		0	0	ADD An[~], An[~], imm16 [, next A]	Add long constant to accumulator (or offset accumulator if
				ADDS An[~], An[~], pma16	A~=1) and store result to accumulator (~A=0) or offset
					accumulator (~A=1). ALU status modified.
0		0	1	MOV An[~], imm16 [, next A]	Load long constant to accumulator (~A=0 or 1). ALU status is
				MOVS An[~], pma16	modified.
0		1	0	SUB An[~], An[~], imm16 [, next A]	Subtract a long constant from the accumulator (A~=0 or 1).
				SUBS An[~], An[~], pma16	Store the result in accumulator (~A=0) or offset accumulator
					(~A=1). ALU status is modified.
0		1	1	CMP An[~], imm16 [, next A]	Modify ALU status by subtracting a long constant from accu-
				CMPS An[~], pma16	mulator (A~=0) or from offset accumulator (A~=1). Neither ac-
					cumulator or offset accumulator is modified
1		0	0	OR An[~], An[~], imm16 [, next A]	Logical OR a long constant with accumulator (A~=0 or 1).
				ORS An[~], An[~], pma16	Store the result in accumulator(~A=0) or offset accumulator
					(~A=1). ALU status is modified.
1		0	1	AND An[~], An[~], imm16 [, next A]	Logical AND a long constant with accumulator (A~=0 or
				ANDS An[~], An[~], pma16	1).Store the result to accumulator(~A=0 or 1) . ALU status is
					modified.
1		1	0	XOR An[~], An[~], imm16 [, next A]	Logical exclusive OR a long constant with accumulator (A~=0
				XORS An[~], An[~], pma16	or 1) Store the result to accumulator (~A=0 or 1). ALU status is
					modified.
1		1	1	MOV MR, imm16 [, next A]	Load a long constant to MR in signed mode. No change in
					status.

4.4.3Class 3 Instruction: Accumulator Reference

These instructions reference the accumulator and, in some instances, specific registers for transfers. Some instructions use a single accumulator operand and others use both the accumulator and the offset accumulator to perform operations between two accumulator values. The A~ bit in the instruction word reverses the sense of the addressed accumulator and the addressed offset accumulator. In general, if A~=1, the instruction uses the offset accumulator as the input operand on single accumulator operand instructions. It interchanges the arithmetic order (subtract, compare, multiply–accumulate, etc.) of the two operands when both are used. Exceptions to the rule are the instructions NEGAC[S], NOTAC[S], MULSPL[S], MULAPL[S], MULTPL[S], SHLSPL[S], SHLTPL[S] and SHLAPL[S], which use the reverse A~ control (A~=1 for accumulator, A~=0 for offset accumulator). The ~A bit in the instruction word controls the destination of the result to be the accumulator (~A=0) or the offset accumulator (~A=1).

In addition to basic accumulator arithmetic functions this class also includes an accumulator lookup instruction and several register transfer instructions

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