4 ms·
I think of it as having a nice set of 256 “registers”, in the zero page at addresses 0-255. I think of the A register as kind of an intermediate location for da
by dietrichepp 3y ago
I think of it as having a nice set of 256 “registers”, in the zero page at addresses 0-255. I think of the A register as kind of an intermediate location for data that is going from memory to the ALU or the ALU to memory. The article says as much:
> In effect the 6502’s ‘page zero’ in memory provides a large number of ‘pseudo’ 8 and 16-bit registers, slower than real registers, but still faster and more versatile than having to use other parts of memory. A skilled programmer making effective use of ‘page zero’ could write code that was fast when compared to other 8-bit designs.
I haven’t done a lot of 6502, though. I learned Basic on the Apple II when I was young but moved to Think Pascal, HyperCard, and CodeWarrior on the Mac.
- bogantech 3y ago> I think of it as having a nice set of 256 “registers”, in the zero page at addresses 0-255. It becomes a pain making sure the monitor/bios and any programs don't stomp on each others zero page locations though. Then if you start daydreaming about multitasking you have to worry about shoveling the contents off somewhere else whenever you switch tasks. The 65816 at least can relocate zero page & the stack but if you're going 16 bit you're better off going M68K
- Brananarchy 3y agoBetter off unless you're targeting the SNES