Hardware simulator

Catalogue

1. 1. Hardware simulator (unit 1.5)
   1. 1.1. Feel free to “kick the tires”!
   2. 1.2. Script-based simulation
   3. 1.3. Script-based simulation with compare files
2. 2. Hardware Construction Projects
   1. 2.1. System architects
   2. 2.2. Developers
3. 3. Multi-Bit Buses
   1. 3.1. Some Syntax Notes

这两个单元主要是介绍了软件怎么用，怎么test和生成output。
简介了Hardware Description Language (HDL) (unit 1.4)

Hardware simulator (unit 1.5)

Feel free to “kick the tires”!

• The simulator is written in Java.
• The download link is here.
• The simulator is invoking in nand2tetris/tools/HardwareSimulator.bat.
• It can check both output pins and internal pins.

Script-based simulation

HDL code .hdl + test script tst —–> into simulator —–> Output file .out

Note that this way to debug by checking the output file is rare in real life testing, because a real chip is far more complex than an Xor chip. A more systematic and planned method is going to be introduced next.

Script-based simulation with compare files

The compare file .cmp, whose previous incarnation (前身) is a correct output file.

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Hardware Construction Projects

• System architects

  • chip API
  • test script
  • compare file

• Developers

  • build the chip with HDL

In this course, we play the role of developers.

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Multi-Bit Buses

“Bus” means “many” in Latin.

Some Syntax Notes

Say, an integer is aaa[16]:

• aaa is the integer’s name
• aaa[0] is its first bit. （注意是LSB，就是最低位/最右边的一位。）
• aaa[7..15], with 2 dots in the middle, means its sub-bus.

Other syntaxes:

• true and false can represent a bus with constant signal of any width.

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补充一个后面答疑问到的几个关于HDL的问题：

Q. 这门课中的HDL语言是现实中使用的吗？
A. 很相似，比如和VHDL相比，VHDL可能在基本的HDL基础上加了一些类C的语言，比如For这些。（所以code block我也就近用了VHDL的高亮）