For those miss Arnt's point, see how the real life Z80 code looked like here: https://www.tablix.org/~avian/spectrum/rom/zx82.txt https://www.tablix.org/~avian

For those miss Arnt's point, see how the real life Z80 code looked like here: https://www.tablix.org/~avian/spectrum/rom/zx82.txt https://www.tablix.org/~avian/spectrum/rom/zx82.txt That's the disassembly of the whole ZX Spectrum ROM which has the built in BASIC interpreter with the floating point support.