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--- analyticalengine:zeroingtemporaries [2015-04-22 20:11] – typo rainer
+++ analyticalengine:zeroingtemporaries [2015-04-22 22:19] (aktuell) – Zero before store asserted rainer
@@ Zeile 6: / Zeile 6: @@
 That's why I think a zero is missing in line 24 column V<sub>13</sub>.
+From the mechanical plans, it might be required -- but not mentioned in the papers -- that to transfer a value from the mill via the outgress shaft to the store, that store must be zero, otherwise a digit-wise add (without carry) would be done.
+The Bernoulli number example fits perfectly into this scheme.
+In case that an input operand is replaced by the result, it is no problem to use the -- anyhow quicker -- zeroing load.
+Checking the table shows that all (working-) variables are zeroed before replaced with another value:
+  * In line 9, V<sub>11</sub> is set, but was cleared in line 6
+  * in line 15, V<sub>8</sub> is set, was initially zero, and is zeroed in the next line, so if looped, will be zero again
+  * in line 19, the same is true for V<sub>9</sub>
+  * same in line 20
+Thus, it is clear that in line 24, the table should have a zero for V<sub>13</sub>.
+So it is probably not a mere extra, but necessary for the correct functioning.
+===== Note =====
 Zeroing out intermediate values still seems to be current practice when Alan Turing wrote his //On Computational Numbers…//; on  page 232: