nand2/04_Machine_Language
2024-10-17 14:38:28 -04:00
..
leds.asm add verilog files for project one through five 2024-10-17 14:38:28 -04:00
Makefile changed python tools to python3.11 2023-08-04 16:44:31 +02:00
mult.asm add verilog files for project one through five 2024-10-17 14:38:28 -04:00
Readme.md added v2.0 2023-01-11 23:04:57 +01:00

04 Machine Language

leds.asm

To test input and output capability of HACK we will write an endless loop, in which HACK reads the state of the buttons BUT[1:0] and writes the result to LED[1:0]. All devices for input and output are mapped to memory addresses starting from 0x1000. The state of BUT[1:0] can be read at memory address 4097 and the two leds LED[1:0] can be switched on and of by writing to memory address 4096. The Assembler in tools already knows the following predefined symbols.

symbol value function
SP 0 stack pointer of VM
LCL 1 local segment of VM
ARG 2 argument of function/method call
THIS 3 pointer to object in heap
THAT 4 pointer to object in heap
R0--R15 0-15 register 0-15
LED 4096 0 LED is off,1 LED is on
BUT 4097 0 BUT pushed down, 1 BUT released up
UART_TX 4098 send byte over UART
UART_RX 4099 receive byte from UART
SPI 4100 read/write to SPI flash rom
SRAM_A 4101 address of SRAM chip for next read/write
SRAM_D 4102 read/write data from/to SRAM chip
GO 4103 switch from BOOT to RUN
LCD8 4104 write 8bit to LCD
LCD16 4105 write 16bit to LCD
RTP 4106 read/write 8bit to RTP
DEBUG0 - DEBUG4 4107 - 4111 reserved for debugging

mult.asm

To test the ALU of HACK we will write a little assembler program, that calculates the multiplication of two integers stored in R0 and R1. The result shoud be stored into R2.

To Test the result we have to load some test values into R0,R1 and R2. After the multiplication is finished we will check the result in R2. To show if the multiplication is correct, we use two strategies:

Use LED to debug

To test mult.asm in real hardware, we can use the LED[1:0] to display if the result is correct or wrong according to:

LED[1:0] output
00 nothing happened yet
01 start multiplication
10 correct result
11 wrong result

Use DEBUG0-4 register

To test mult.asm in simulation, we can use the DEBUG registers. Every time we change the value of R0--R2 we store the new values also to the corresponding register DEBUG0--DEBUG2. This is done by replacing every instance of a code snippet that changes R1 (and R0,R2 accordingly):

@R1
M=<what so ever>

with the code that additionally writes the new value to the DEBUG1 register:

@R1
DM=<what so ever>
@DEBUG1
M=D

Project

  • Implement leds.asm and mult.asm.

  • Put your code in the skeleton file <filename>.asm. To build the .hack binary file, which can than be preloaded to the instruction ROM of HACK in 05_Computer_Architecture/04_HACK, just type:

    $ make leds
    

    or

    $ make mult
    

    This will invoke the assembler and copy the produced binary file ROM.hack in the appropriate folder 05_Computer_Architecture/04_HACK.

  • To run the programms you first have to build a HACK computer. This is done in 05_Computer_Architecture.