HDL-PC.hdl,但从x2 8位寄存器开始

问题描述

因此,我基本上需要创建一个PC.hdl,但要从x2 8位寄存器开始。这是起点:

// This file is BASED ON part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken,MIT Press.
// File name: project03starter/a/PC.hdl

/**
 * A 16-bit counter with load and reset control bits.
 * if      (reset[t] == 1) out[t+1] = 0
 * else if (load[t] == 1)  out[t+1] = in[t]
 * else if (inc[t] == 1)   out[t+1] = out[t] + 1  (integer addition)
 * else                    out[t+1] = out[t]
 */

CHIP PC {
    IN in[16],load,inc,reset;
    OUT out[16];

    PARTS:
    // Something to start you off: you need *two* 8-bit registers
    Register(in=nextLow,out=out[0..7],out=currentLow,load=true);
    Register(in=nextHigh,out=out[8..15],out=currentHigh,load=true);

    // Handling 'inc' to increment the 16-bit value also gets tricky
    // ... this might be useful
    And(a=inc,b=lowIsMax,out=incAndLowIsMax);
    // ...

    // The rest of your code goes here...
} 

我知道如何仅通过处理16位来正常执行此操作,但是我不确定如何使用8位寄存器来执行此操作。

有人可以帮助我提供正确的解决方案吗?

谢谢。

解决方法

假设您有一个8位加法器,则可以使用2个加法器实现一个16位加法器,一个加法器计算currentLow + 1,另一个加法器计算currentHigh +(低位加法器的输出)