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Add Logical

The second operand is added to the first operand, and the sum is placed in the first-operand location. The occurrence of a carry out of the sign position is recorded in the condition code.

Logical addition is performed by adding all 32 bits of both operands without further change to the resulting sign bit. The instruction differs from ADD in the meaning of the condition code and in the absence of the interruption for overflow.

If a carry out of the sign position occurs, the leftmost bit of the condition code is made one. In the absence of a carry, the bit is made zero. When the sum is zero, the rightmost bit of the condition code is made zero. For a nonzero sum, the bit is made one.

Resulting Condition Codes
0 ~ Sum is zero, with no carry
1 ~ Sum is not zero, with no carry
2 ~ Sum is zero, with carry
3 ~ Sum is not zero, with carry

Program Exceptions:
Access (fetch, operand 2 of AL only)



Next: And Up: Instructions Previous: Add Halfword


A.Daviel,TRIUMF