A multimedia execution unit configured to perform vectored floating point
and integer instructions. The execution unit may include an add/subtract
pipeline having far and close data paths. The far path is configured to
handle effective addition operations and effective subtraction operations
for operands having an absolute exponent difference greater than one. The
close path is configured to handle effective subtraction operations for
operands having an absolute exponent difference less than or equal to one.
The close path is configured to generate two output values, wherein one
output value is the first input operand plus an inverted version of the
second input operand, while the second output value is equal to the first
output value plus one. Selection of the first or second output value in
the close path effectuates the round-to-nearest operation for the output
of the adder.