pseudo assembly - Tutorial

step 1 of 6

Basic Data Declaration

Let's start with the basics. In pseudo assembly, you can declare data using DC (Define Constant) and DS (Define Space).

These aren't executable instructions - they're data declarations, like a data section in a real assembler, so all of them must come before any executable instruction in your program.

Task:

Create a variable called NUMBER with value 42 using the DC instruction.

Hint:

Use: VARIABLE_NAME DC INTEGER(value)

vim

step 2 of 6

Load and Store Operations

Now let's learn to move data between memory and registers using L (Load) and ST (Store).

Task:

1. Create a variable VALUE with value 100
2. Load it into register R1
3. Create space for RESULT
4. Store R1 into RESULT

Instructions:

• L reg, memory - Load from memory to register
• ST reg, memory - Store from register to memory
• DS INTEGER - Define space for one integer

vim

step 3 of 6

Arithmetic Operations

Let's perform arithmetic operations: Add, Subtract, Multiply, and Divide.

Task:

Calculate: (10 + 5) * 3 and store the result.
Use registers R1, R2, R3 for intermediate calculations.

Arithmetic Instructions:

• A reg, memory - Add memory value to register
• S reg, memory - Subtract memory value from register
• M reg, memory - Multiply register by memory value
• AR reg1, reg2 - Add register to register

vim

step 4 of 6

Loops with Jumps

Learn to create loops using labels and conditional jumps.

Task:

Create a loop that counts from 1 to 5 and stores the final counter value in RESULT.
Use a loop with a label and conditional jump.

Jump Instructions:

• LABEL instruction - Define a label
• J LABEL - Unconditional jump
• JZ LABEL - Jump if zero flag is set
• C reg, memory - Compare (sets flags)

vim

step 5 of 6

Final Challenge - Calculate Factorial

Put it all together! Calculate the factorial of a number using all the concepts you've learned.

Challenge:

Write a program that calculates 4! (4 factorial = 4 × 3 × 2 × 1 = 24)
Store the result in a variable called FACTORIAL.

Algorithm:

1. Start with N = 4
2. Initialize result = 1
3. While N > 0: result = result × N, N = N - 1
4. Store result in RESULT

vim

🎉 Congratulations!

You've completed the pseudo assembly tutorial!

Want to go deeper? Check out Programming from the Ground Up by Jonathan Bartlett - free and open source.

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