| 摘要 |
An optimized 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 data path is configured to handle effective addition operations, as well as effective subtraction operations for operands having an absolute exponent difference greater than one. The close data path, conversely, is configured to handle effective subtraction operations for operands having an absolute exponent difference less than or equal to one. The close data path may include an adder unit configured to generate a first and second output value. The first output value is equal to 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. The two output values are conveyed to a multiplexer unit, which selects one of the output values as a preliminary subtraction result. Selection of the first or second output value in the close data path effectuates the round-to-nearest operation for the output of the adder. The execution unit may also be configured to perform floating point-to-integer and integer-to-floating point conversions.
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