When you execute a file, how does it start up?
Does it start at the top of the file, and the values tell it which address to go next?
I need to get everything straight.
Are you talking about PC executables?
On NES, at power on, the mapper computes which banks are fixed and which are switchable, and the initial values of the switchable banks. Then the CPU reads a 16-bit little-endian value from the locations mapped to $FFFC and $FFFD in CPU space and sets the program counter to this value.
.nes ROM's don't equal executables. He isn't being very specific.
I didn't even understand the question, as it really isn't clear what you're talking about.
If you are talking about NES binaries, execution starts at the location pointed by the values at $FFFC and $FFFD, as tepples said. Programs are just a sequence of commands, and the CPU auto-increments the Program Counter (the internal register that point to the next instruction to execute) as it reads and executes each command.
Is that what you're talking about?
Ah, thanks, that clears up alot.
I was mostly talking about NES but thanks for the other info.
Because I didn't know exactly how it knows which addresses to grab values from to put into the registers.