| 摘要 |
A floating point unit (60) capable of executing projection instructions provides performance improvement in multiple precision floating point arithmetic. The projection instructions provide for obtaining partial sequences of numbers, products, and sums which have definite alignments and widths which a programmer can set. This allows very fast computation of both individual intermediate computations and final results. A range projection instruction (210, 410) builds a mask with an exponent from one source (230, 430) and a mantissa from another (240, 440). A project instruction (610) builds a result by masking (660) mantissa bits in a source operand after alignment (630) with a mask. Projection multiply (810), add (1000), and subtract instructions build results by masking (850, 1070) mantissa bits of unrounded partial results after alignment (830, 1020, 1040) with a mask. |
