| 摘要 |
<p>PURPOSE:To reduce the overhead produced when a subroutine is called and to attain the effective use of a register set by using a means to set partly the adjacent register sets with overlap for a register bank consisting of an internal RAM. CONSTITUTION:When a register number is designated in an instruction, this register number is added to the contents of a register pointer. Then an area (register) of an internal RAM pointed by the result of this addition is accessed. For instance, a parameter is set to a register 7 from a register 0 in a main routine and a subroutine is called out. Then '8' is subtracted from the contents of a register pointer at the side of the subroutine. As a result, the register 0 is mapped to the register 7 in the main routine and a register 8 is mapped to a register 15 in the subroutine respectively. Thus the parameter can be transferred with no transfer of data. Furthermore, the contents of the register pointer can be reduced by an amount equal to the number of registers necessary for the subroutine. Then the internal RAM is effectively used.</p> |
