This instruction is useful for branching to a portion of the program called a
subroutine or procedure. When executed, the BSA instruction stores the address
of the next instruction in sequence (which is available in PC) into a
memory location specified by the effective address. The effective address plus
one is then transferred to PC to serve as the address of the first instruction in
the subroutine. This operation was specified in Table 5-4 with the following
register transfer: show more...