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对于RS,RX,SI和SS指令的编址,汇编程序必须指定一基数寄存器和位移(displacement)。通知汇编程序那些寄存器是基数,且用地址常数送入这些寄存器,这是程序设计人员的职责。法则是对于每个基数-加-位移地址,必须有个USING指令,它在有效指令地址的4096字节以内有一个地址。程序设计员借助USING指令告诉汇编程序某一寄存器含有某一专门地址。这并不产生代码送入寄存器去;它只是说明所指定的寄存器含有指定的地址。
For addressing of RS, RX, SI, and SS instructions, the assembler must specify a base register and displacement. It is the responsibility of the programmer to inform the assembler which registers are the base, and address them into these registers. The rule is that for each cardinality-plus-shift address, there must be a USING instruction that has an address within 4096 bytes of the valid instruction address. Programmers use the USING directive to tell the assembler that a register contains a specific address. This does not result in code being sent to the register; it merely indicates that the specified register contains the specified address.