For a university project I programmed for an Arduino Uno (ATmega328P). Debugging performance problems, we found out that a switch (implemented with a bunch of i

For a university project I programmed for an Arduino Uno (ATmega328P). Debugging performance problems, we found out that a switch (implemented with a bunch of if/else ifs) with about 12 branches used ca. 200 clock cycles just checking the 12 conditions. Turns out the ATmega328P has only 8bit registers and the ALU operates on 8bit values. We were using 32-bit datatypes in the conditions, which the ATmega328P loaded and compared byte per byte, each comparison (incl. jump etc) cost us something like 16 cycles. So yeah, the size of the datatypes definitely mattered for us :) edit: as an addition, we needed quite a while to figure out (and were quite surprised when we did) that ints are 16bit and longs 32bit on this platform/compiler. i guess this comes down to the general question of explicit vs implicit, and i usually do prefer the former.