Pointers in STL

Hey guys.
I have problem with pointers in STL. My program has to write 255 to MB [ MD 300]. Let's say I write 20 to the MD 300, MB [20]=255, I tried to do this way, but it doesn't work.

There are two errors in your code.
1) The left 3 bits in the address register are for the bit-addresses .0 - .7. So you have shift the value you want to access by 3.

2) If you want always access M area, you are using a so called register-indirect area-internal addressing. You have to specify the memory area you want get access to

The code should be

It works. Thank you.