I'm reading about the 6502 processor's instruction set from the many links at 6502.org, and one tutorial states:
The stack pointer (S) points to a byte on Page 1, that is, to a byte whose address is from 0100 to 01FF, where the last two digits are supplied by S. When a byte is pushed on the stack, it is written at the address in S, and then S is decremented.
The S register is 1 byte, so it obviously holds a value from 00 to FF, but since it decrements upon pushes, when nothing has yet been pushed on, it must start at FF. Does the physical hardware (transistors) in the chip set all the bits in that register to '1' when the chip gets its first breath of power?
I just like to know the low-level details.