A register which performs memory address arithmetic for random access memory (RAM) resident stack applications. It contains three 4-bit registers intended for program counter, stack pointer, and operand address use.; 一種寄存器,為常駐隨機(jī)存取存儲器堆棧的應(yīng)用執(zhí)行地址運(yùn)算。它包含3個4位寄存器,分 別用作程序計數(shù)器,堆棧指針和存放操作數(shù)地址。