Your First Program

Let us begin with the smallest pleasant thing: printing a character.

    LDI 72
    PRT
    HLT

What happens here

• LDI 72 loads the decimal value 72 into register A
• PRT writes the byte in A to output
• HLT stops the machine

Since ASCII character 72 is H, the program prints H.

The same program written in hexadecimal looks like this:

    LDI $48
    PRT
    HLT

A slightly friendlier example

The repository includes a full string-printing example in examples/hello.s32. Here is the heart of it:

    LDP text
    JSR printstr
    HLT

printstr:
@loop:
    LDA
    CMI $00
    JEQ @done
    PRT
    IDP
    JMP @loop
@done:
    RET

This shows a very typical T32 pattern:

• DP points at some data
• LDA pulls the current byte into A
• a compare sets flags
• a conditional jump decides what to do next

Why this example matters

Even this tiny string printer demonstrates several important ideas:

• memory is read through DP
• A is the value you compute with and print
• flags let you make decisions
• subroutines let you reuse code without adding more registers