| 摘要 |
PURPOSE:To decrease the number of dynamic steps of a program containing many repeated processings by providing one more more registers which can prescribe a return address from a subroutine. CONSTITUTION:A stack 102 stores a first return address from a subroutine, and a register 103 stores a second return address from the subroutine. An instruction fetching means 108 fetches an instruction stored in an address designated by a program counter 101. When an instruction decoded by a decoder 9 is a subroutine call instruction, the contents of a counter 101 are pushed to the stack 102, and a call destination address if transferred to the counter 101. Also, when said instruction is a return 1 instruction, the contents of the stack 102 are popped to the counter 101, and when said instruction is a return 2 instruction, the contents of the stack 102 are popped, but the contents of the register 103 are transferred to the counter 101. In such a way, by one instruction, a return and an unconditional jump can be executed.
|
