Research and Advances

Two methods for word inversion on the IBM 709: method 1

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In some logical problems it is necessary or convenient to invert the bit structure of a word, i.e., replace bit i by bit n + 1 - i for i = 1, 2, ···, n, thus creating a mirror image. The method described here exploits the CAQ instruction of the IBM 709 (or 7090) to accomplish such an inversion rapidly (n = 36).

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