Returns the contents stored at the given memory address
Implemented by: altair8K, a2int, Applesoft, CBM, Atari, msatari, level2, trscolor, colormc, Sinclair, GWBASIC, MSX, bw32, ABasiC, QBasic, VBDOS, FreeBASIC, ugBASIC
With variations: altair12K (requires substraction if address is > 32767), ti994ext (through CALL, for assembly subprograms), Gambas
Also written as: