Extremely CISC instructions

On Tue, 2021-08-24 at 01:38 +0100, Tom Stepleton via cctalk wrote: IBM 1401 was a character-by-character machine, so most operations had costs proportional to field length. One especially expensive (but very useful) operation was "move characters and edit." Assuming a 17-character control word has been loaded to the destination, e.g. "$ ? , ?0. &CR&**" to edit a data field "00257426" with a "negative" zone bit on the low- order digit, producing "$ ?2,574.26 CR **" requires 41 memory accesses (including seven to fetch the instruction) -- 0.4715 milliseconds. See pages 41-43 at?http://www.bitsavers.org/pdf/ibm/1401/A24-1403-5_1401_Reference_Apr62.pdf On a machine where ?the "Expanded Print Edit Feature" was added, the instruction cost even more. For example, the "Floating Dollar Sign" moves the dollar sign to immediately to the left of the most significant digit. This (and asterisk protection) was to prevent somebody from adding digits between a left-justified dollar sign and leading digits on printed checks. The above edit would cost two more memory cycles. If the datum had had more leading zeroes, even more cycles would have been required.

See pages 82-84. Another expensive instruction was the simpler "move characters and suppress zeros" instruction. See page 38.