A Turing machine is a pushdown automaton where the stack is no longer LiFo.
what does it mean for a turing machine to return a given value? is that possible, or does it just halt?
Input is symbol on tape at head, and internal state. Output is:
+ write symbolt to where head is + move left or write or halt. + new internal state
This mapping table is the program. Input to the program can be done by setting the values of the tape at the start.
testing for if branches and with target
starting cycle. read next instruction pointer. read that instruction. read additional bytes needed. do instruction. wait clock cycles
cpu instructions can vary by required clocks cpu instructions have addressing modeds. they also take addresses. defined address length?
cpu has status register. series of bits about status last instruction etc
can address using page and offset. two hex for each. can write eg 0x00FF. last byte of irst page