43 lines
2.0 KiB
Plaintext
43 lines
2.0 KiB
Plaintext
// This file is part of www.nand2tetris.org
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// and the book "The Elements of Computing Systems"
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// by Nisan and Schocken, MIT Press.
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// File name: projects/05/CPU.hdl
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/**
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* The Hack CPU (Central Processing unit), consisting of an ALU,
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* two registers named A and D, and a program counter named PC.
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* The CPU is designed to fetch and execute instructions written in
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* the Hack machine language. In particular, functions as follows:
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* Executes the inputted instruction according to the Hack machine
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* language specification. The D and A in the language specification
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* refer to CPU-resident registers, while M refers to the external
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* memory location addressed by A, i.e. to Memory[A]. The inM input
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* holds the value of this location. If the current instruction needs
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* to write a value to M, the value is placed in outM, the address
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* of the target location is placed in the addressM output, and the
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* writeM control bit is asserted. (When writeM==0, any value may
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* appear in outM). The outM and writeM outputs are combinational:
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* they are affected instantaneously by the execution of the current
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* instruction. The addressM and pc outputs are clocked: although they
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* are affected by the execution of the current instruction, they commit
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* to their new values only in the next time step. If reset==1 then the
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* CPU jumps to address 0 (i.e. pc is set to 0 in next time step) rather
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* than to the address resulting from executing the current instruction.
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*/
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CHIP CPU {
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IN inM[16], // M value input (M = contents of RAM[A])
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instruction[16], // Instruction for execution
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reset; // Signals whether to re-start the current
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// program (reset==1) or continue executing
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// the current program (reset==0).
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OUT outM[16], // M value output
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writeM, // Write to M?
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addressM[15], // Address in data memory (of M)
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pc[15]; // address of next instruction
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PARTS:
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// Put your code here:
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} |