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Author Bernstein, Herbert J.
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
Language English
Subject Keyword Compiling multiplications ♦ Fixed-point arithmetic
Abstract With reference to the article by H. T. Gladwin [1], (Comm.) it should be noted that the technique described is a limited subset of techniques known for many years, particularly to programmers for machines lacking an integer multiply instruction, CDC 6000 PPU's for example. It is easier to present and implement more generally applicable techniques, such as full decomposition into “runs” of 0's and 1's to yield representation as: ∑Li=0(2m(i) - 2n(i)) which may be further compressed by replacing such terms as -2m+1 + 2m by -2m. In decomposing numbers from the right on a CDC 6000 in particular, special techniques are possible [2].Finally, Gladwin failed to credit the CDC RUN compilers, in use for over six years on the very machines he discussed, for doing a large number of constant multiplies by shifts and adds (subroutine SHM in overlay RUN1).
Description Affiliation: Brookhaven National Lab, Upton, NY (Bernstein, Herbert J.)
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2005-08-01
Publisher Place New York
Journal Communications of the ACM (CACM)
Volume Number 15
Issue Number 8


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Source: ACM Digital Library