Building Own Computer with Nand2Tetris: Project III
21 April 2022
After a long break, I was able to find time for this course I took from Coursera and I finished the project of the third week. I should point out that I was in a bit of a rush to design the Program Counter and got help from the discussion forums.
This week's project is totally about memories.
I hope to finish this course soon. In addition, I will add two homework projects that I will do in my FPGA VHDL course, which I took at school in parallel with the course, to my blog soon.
Bit
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/03/a/Bit.hdl
/**
* 1-bit register:
* If load[t] == 1 then out[t+1] = in[t]
* else out does not change (out[t+1] = out[t])
*/
CHIP Bit {
IN in, load;
OUT out;
PARTS:
Mux (a=outDFF, b=in, sel=load, out=wire1);
DFF (in=wire1, out=out, out=outDFF);
}Register
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/03/a/Register.hdl
/**
* 16-bit register:
* If load[t] == 1 then out[t+1] = in[t]
* else out does not change
*/
CHIP Register {
IN in[16], load;
OUT out[16];
PARTS:
Bit (in=in[0], load=load, out=out[0]);
Bit (in=in[1], load=load, out=out[1]);
Bit (in=in[2], load=load, out=out[2]);
Bit (in=in[3], load=load, out=out[3]);
Bit (in=in[4], load=load, out=out[4]);
Bit (in=in[5], load=load, out=out[5]);
Bit (in=in[6], load=load, out=out[6]);
Bit (in=in[7], load=load, out=out[7]);
Bit (in=in[8], load=load, out=out[8]);
Bit (in=in[9], load=load, out=out[9]);
Bit (in=in[10], load=load, out=out[10]);
Bit (in=in[11], load=load, out=out[11]);
Bit (in=in[12], load=load, out=out[12]);
Bit (in=in[13], load=load, out=out[13]);
Bit (in=in[14], load=load, out=out[14]);
Bit (in=in[15], load=load, out=out[15]);
}RAM8
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/03/a/RAM8.hdl
/**
* Memory of 8 registers, each 16 bit-wide. Out holds the value
* stored at the memory location specified by address. If load==1, then
* the in value is loaded into the memory location specified by address
* (the loaded value will be emitted to out from the next time step onward).
*/
CHIP RAM8 {
IN in[16], load, address[3];
OUT out[16];
PARTS:
DMux8Way (in=load, sel=address, a=load0, b=load1, c=load2, d=load3, e=load4, f=load5, g=load6, h=load7);
Register (in=in, load=load0, out=out0);
Register (in=in, load=load1, out=out1);
Register (in=in, load=load2, out=out2);
Register (in=in, load=load3, out=out3);
Register (in=in, load=load4, out=out4);
Register (in=in, load=load5, out=out5);
Register (in=in, load=load6, out=out6);
Register (in=in, load=load7, out=out7);
Mux8Way16 (a=out0, b=out1, c=out2, d=out3, e=out4, f=out5, g=out6, h=out7, sel=address, out=out);
}RAM64
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/03/a/RAM64.hdl
/**
* Memory of 64 registers, each 16 bit-wide. Out holds the value
* stored at the memory location specified by address. If load==1, then
* the in value is loaded into the memory location specified by address
* (the loaded value will be emitted to out from the next time step onward).
*/
CHIP RAM64 {
IN in[16], load, address[6];
OUT out[16];
PARTS:
DMux8Way (in=load, sel=address[0..2],
a=loadRAM0,
b=loadRAM1,
c=loadRAM2,
d=loadRAM3,
e=loadRAM4,
f=loadRAM5,
g=loadRAM6,
h=loadRAM7
);
RAM8 (in=in, load=loadRAM0, address=address[3..5], out=outRAM0);
RAM8 (in=in, load=loadRAM1, address=address[3..5], out=outRAM1);
RAM8 (in=in, load=loadRAM2, address=address[3..5], out=outRAM2);
RAM8 (in=in, load=loadRAM3, address=address[3..5], out=outRAM3);
RAM8 (in=in, load=loadRAM4, address=address[3..5], out=outRAM4);
RAM8 (in=in, load=loadRAM5, address=address[3..5], out=outRAM5);
RAM8 (in=in, load=loadRAM6, address=address[3..5], out=outRAM6);
RAM8 (in=in, load=loadRAM7, address=address[3..5], out=outRAM7);
Mux8Way16 (sel=address[0..2], out=out,
a=outRAM0,
b=outRAM1,
c=outRAM2,
d=outRAM3,
e=outRAM4,
f=outRAM5,
g=outRAM6,
h=outRAM7);
}RAM512
// This file is part of the materials accompanying the book
// "The Elements of Computing Systems" by Nisan and Schocken,
// MIT Press. Book site: www.idc.ac.il/tecs
// File name: projects/03/b/RAM512.hdl
/**
* Memory of 512 registers, each 16 bit-wide. Out holds the value
* stored at the memory location specified by address. If load==1, then
* the in value is loaded into the memory location specified by address
* (the loaded value will be emitted to out from the next time step onward).
*/
CHIP RAM512 {
IN in[16], load, address[9];
OUT out[16];
PARTS:
DMux8Way (in=load, sel=address[0..2],
a=loadRAM0,
b=loadRAM1,
c=loadRAM2,
d=loadRAM3,
e=loadRAM4,
f=loadRAM5,
g=loadRAM6,
h=loadRAM7
);
RAM64 (in=in, load=loadRAM0, address=address[3..8], out=outRAM0);
RAM64 (in=in, load=loadRAM1, address=address[3..8], out=outRAM1);
RAM64 (in=in, load=loadRAM2, address=address[3..8], out=outRAM2);
RAM64 (in=in, load=loadRAM3, address=address[3..8], out=outRAM3);
RAM64 (in=in, load=loadRAM4, address=address[3..8], out=outRAM4);
RAM64 (in=in, load=loadRAM5, address=address[3..8], out=outRAM5);
RAM64 (in=in, load=loadRAM6, address=address[3..8], out=outRAM6);
RAM64 (in=in, load=loadRAM7, address=address[3..8], out=outRAM7);
Mux8Way16 (sel=address[0..2], out=out,
a=outRAM0,
b=outRAM1,
c=outRAM2,
d=outRAM3,
e=outRAM4,
f=outRAM5,
g=outRAM6,
h=outRAM7);
}RAM4K
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/03/b/RAM4K.hdl
/**
* Memory of 4K registers, each 16 bit-wide. Out holds the value
* stored at the memory location specified by address. If load==1, then
* the in value is loaded into the memory location specified by address
* (the loaded value will be emitted to out from the next time step onward).
*/
CHIP RAM4K {
IN in[16], load, address[12];
OUT out[16];
PARTS:
DMux8Way (in=load, sel=address[0..2],
a=loadRAM0,
b=loadRAM1,
c=loadRAM2,
d=loadRAM3,
e=loadRAM4,
f=loadRAM5,
g=loadRAM6,
h=loadRAM7
);
RAM512 (in=in, load=loadRAM0, address=address[3..11], out=outRAM0);
RAM512 (in=in, load=loadRAM1, address=address[3..11], out=outRAM1);
RAM512 (in=in, load=loadRAM2, address=address[3..11], out=outRAM2);
RAM512 (in=in, load=loadRAM3, address=address[3..11], out=outRAM3);
RAM512 (in=in, load=loadRAM4, address=address[3..11], out=outRAM4);
RAM512 (in=in, load=loadRAM5, address=address[3..11], out=outRAM5);
RAM512 (in=in, load=loadRAM6, address=address[3..11], out=outRAM6);
RAM512 (in=in, load=loadRAM7, address=address[3..11], out=outRAM7);
Mux8Way16 (sel=address[0..2], out=out,
a=outRAM0,
b=outRAM1,
c=outRAM2,
d=outRAM3,
e=outRAM4,
f=outRAM5,
g=outRAM6,
h=outRAM7);
}RAM16K
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/03/b/RAM16K.hdl
/**
* Memory of 16K registers, each 16 bit-wide. Out holds the value
* stored at the memory location specified by address. If load==1, then
* the in value is loaded into the memory location specified by address
* (the loaded value will be emitted to out from the next time step onward).
*/
CHIP RAM16K {
IN in[16], load, address[14];
OUT out[16];
PARTS:
DMux4Way (in=load, sel=address[0..1],
a=loadRAM0,
b=loadRAM1,
c=loadRAM2,
d=loadRAM3);
RAM4K (in=in, load=loadRAM0, address=address[2..13], out=outRAM0);
RAM4K (in=in, load=loadRAM1, address=address[2..13], out=outRAM1);
RAM4K (in=in, load=loadRAM2, address=address[2..13], out=outRAM2);
RAM4K (in=in, load=loadRAM3, address=address[2..13], out=outRAM3);
Mux4Way16 (sel=address[0..1], out=out,
a=outRAM0,
b=outRAM1,
c=outRAM2,
d=outRAM3);
}
Program Counter (PC)
// This file is part of www.nand2tetris.org
// and the book "The Elements of Computing Systems"
// by Nisan and Schocken, MIT Press.
// File name: projects/03/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:
Register (in=outSystem, out=outRegister, out=out, load=true);
Inc16 (in=outRegister, out=outIncrementor);
Mux16 (a=outRegister, b=outIncrementor, sel=inc, out=MuxIncOut);
Mux16 (a=MuxIncOut, b=in, sel=load, out=MuxLoadOut);
Mux16 (a=MuxLoadOut, b=false, sel=reset, out=outSystem);
}