Softcore

Noah Smith

In this softcore assignment we will be using the picoblaze CPU adapted for use on the 7 series FPGA chips. We will us assembly language to write simple programs for this CPU to run.

Task 3:

Workflow:

The workflow for this format of coding is vastly different from normal. It has 3 main steps

1. Write your assembly code

2. Execute assembly code with the compiler (kcpsm6.exe) in our case

3. Generate bitstream using Verilog CPU code and upload to the board

Below is a video demonstration to show that I got this workflow working. It is a simple program that maps each switch to an LED. Below is a picture of the Verliog code used for this segment. The only thing that needs to be changed in this code is the name of our compiled assembly code. This is at line 47, simply rename this to whatever the new assembly code is called.

Task 4: Square Problem

This task was to implement the square problem from the textbook, code and demonstration can be seen below.

Task 5: add 13

This task was to add 13 to whatever the input was, code and demonstration can be seen below.

Task 6: Using a bitmask

This task was to use a bitmask and set the LSB’s to always be 11. We did this using an or bitmask which sets the bits.

AND bitmask: Saves bits

OR bitmask: Sets bits

XOR bitmask: Toggles bits

Task 7: Shifting output

This task was to shift the input 2 bits to the right and then display the output. Assembly code and demonstration are shown.

Task 8: Using Jumps

This task was to get familiar with the jump commands and subroutines. Assembly code and demonstration shown below.

Task 9: Test Function

This task used the test function to evaluate and compare values in the program, essentially an if statement. Code and picture of result below

Task 10: Comp Function

This task was to get the same result as the test function but using the comp function instead. Code and picture of results seen below.

Task 11: Adding input

This task was to write assembly code to count the number of input switches we had flipped, then display that number in binary on the output LED’s. Code and video demonstration below.