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Dave Britten · (This post was last modified: 02-11-2020 01:28 PM by Dave Britten.)

Somehow I've gone all this time without realizing that RCL Σ+ can be used to recall ΣX and ΣY to X and Y on quite a few models. Which models support this? I've only had a chance to check a few so far.

45: I think this was a yes, I'll have to double check
80: No (no stat regs, only very basic one-variable summations that work entirely on the stack)
65: No (no built in stat functions; what about the 67 which has them?)
25: Haven't tested yet, ROM was really packed to the brim so it might have been left out
38E/C: No
41C: No (Σ+ is a shortcut for 01 with STO/RCL/GTO/XEQ)
12C: No
15C: Yes
16C: No (no summation/stat functions)
27S: No (list-based stats, not RPN, no Σ+ key)
32S, 32SII: No (Σ+ becomes the F key for STO/RCL/GTO/XEQ)
42S: No (Σ+ becomes a menu key for the variable menu when STO/RCL is active, and TOP.FCN can't be used to get to Σ+ while STO/RCL are pending); SUM function does the same thing but overwrites X and Y without lifting the stack

Do any support STO Σ+ to store two values directly into the ΣX and ΣY registers?