Notes on the CPU Emulator

• 11/28 For more in-depth information about the test script file format (*.tst) refer to the Appendix B of the nand2tetris book.
• 11/24 How to implement “RAM[RAM[x]] = RAM[y]”?
  @y
  D=M
  @x
  A=M
  M=D
• 11/23 The test script file Mult.asm works as follows.
  1. Set the operands (RAM[R0] and RAM[R1]).
  2. Run the program for some time (repeat xxx)
  3. Print the output (RAM[R0], RAM[R1], RAM[R2])
  Therefore, if your program doesn't finish all the computations within the number of clocks (the value after repeat) the CPUEmulator may conclude that your program is incorrect. If you think this is the case, just increase the number of clocks for that test. (Note that this may increase the running time.)
• 11/22 How to implement “RAM[z]=RAM[x]+RAM[y]”?
  @x
  D=M
  @y
  D=D+M
  @z
  M=D
• 11/22 To pass a negative constant value. (We can pass only a positive value using an A-instruction due to its 15-bit limit.)
  Example: to store -123 in RAM[x].
  @123
  D=-A
  @x
  M=D
• 11/22 (For MacOS users) You should install the Java SDK (not the JRE) version ≥1.8 here to make the screen work correctly. Refer to this page for more information.