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> The Sinclair Scientific was able to reduce complexity by using reverse Polish notation, in which mathematical operators come after the numbers they are operat
by roelschroeven 6y ago
> The Sinclair Scientific was able to reduce complexity by using reverse Polish notation, in which mathematical operators come after the numbers they are operating on—for instance, “5 + 4 =” becomes “5 4 +.”
It's not really RPN though. RPN lets you write "2 × (5+4)" as "2 5 4 + ×", but the Sinclair Scientific doesn't support that. It would have needed a stack for that, which wasn't available. Instead each operation simply acts on the previous result. You'd have to use "5 + 4 + 2 ×" instead.
Still very impressive how they managed to accomplish all that using that simple TI chip and only 320 instructions.
- ec109685 6y agoIt’s not “5 4 + 2 x”?
- morcheeba 6y agochanging the order like that doesn't extend to "(5+4)*(3+2)"
- roelschroeven 6y agoThat would be pretty cumbersome to calculate. I guess you'd have to remember the intermediate result. On paper, since the calculator didn't have any memory function.
- duskwuff 6y agoThat'd give you 54 x 2. You have to press + to delimit the initial value.
- roelschroeven 6y agoActually 5.4 × 2; for 54 you have to enter 54E1 (5.4 × 10^1).
- thaumasiotes 6y agoTechnically, you still need delimiters in RPN, so "2 5 4 + ×" won't get you anything, because it's invalid. You need "2 ENTER 5 ENTER 4 + ×" But that is both mentally more difficult to handle and physically more difficult to input than "5 ENTER 4 + 2 ×", so I wouldn't count this as a strike against the Sinclair even theoretically.