Therefore, it is useful to check the overflow flag after adding or subtracting numbers that are represented in two's complement form ( i . e . they are considered signed numbers ).
12.
The overflow flag is thus set when the most significant bit ( here considered the sign bit ) is changed by adding two numbers with the same sign ( or subtracting two numbers with opposite signs ).
13.
In many processor architectures, the overflow flag is cleared by bitwise operations ( and, or, xor, not ), possibly including shifts and rotates, but it may also be left undefined by these.
14.
As the sign bit is the same as the most significant bit of a number " considered " unsigned, the overflow flag is " meaningless " and normally ignored when unsigned numbers are added or subtracted.
15.
When the clock pulse occurs, the sum will be transferred to storage and, if the resulting sum is too large ( i . e ., it is larger than the ALU's output word size ), an arithmetic overflow flag will be set.
16.
In computer processors, the "'overflow flag "'( sometimes called V flag ) is usually a single bit in a system status register used to indicate when an arithmetic overflow has occurred in an operation, indicating that the signed two's-complement result would not fit in the number of bits used for the operation ( the ALU width ).
