21. The contents of the updated program counter are copied into the register X in step 2. 22. Resetting the Program Counter to zero effectively restarts the program, albeit in a potentially different state. 23. When a branch is " taken ", the CPU's program counter is set to the memory. 24. Each PSU has a backup program counter . 25. Each program level had its own set of registers, including a program counter and a status word. 26. Instead, Branch instructions exist that save the program counter to a register and change the register context. 27. PC stands not only for personal computer and politically correct but also printed circuit and program counter . 28. H1, for example, is the program counter . 29. Six of those registers were general registers, one was the program counter , and the other contained status information. 30. Unconditional branches update the program counter with a new address computed in the same way as conditional branches. 