Category: AsmBook

(Updated February 18, 2025) Table of Contents What is and IDE? Hello World A Bigger Example What is an IDE? An Integrated Development Environment, or IDE, is typically a graphical user interface with an editor, compiler, debugger, and much more at your fingertips. One possible IDE combination is Visual Studio Code with x86 and x86 … Read More “Chapter x86_64-1 – The IDE” »

(Updated February 18, 2025) Table of Contents Starting Out With Newer Tech The Intel x86 References Starting Out With Newer Tech Hopefully, you’ve arrived here after explaining the first half of this textbook, which is based on the MOS 6502. If you skipped ahead because this is really what you’re interested in, don’t worry. You … Read More “Chapter x86_64-0 – Where to Begin?” »

(Updated April 22, 2025) signed8bit.asmLoad Workspace ; This is the start of the 8-bit library. define CHROUT $ffd2 define LZF $30 ; This is test code for the 8-bit printing LDY #0 NUMLOOP: LDA NUMBERS,Y STA $31 ; LSB PHA ; SAVE JSR S8OUT ; PRINT AS SIGNED LDA #7 ; ‘\t’ JSR CHROUT PLA … Read More “Chapter 6502-A – 8-, 16-, and 32-bit Printing.” »

(Updated February 18, 2025) Table of Contents Overview Printing Numbers – Part I Bigger Numbers Bigger Math Printing Numbers – Part II Overview In previous chapters, we’ve glossed over details on numbers and mathematics. This is simply because math on this CPU is hard. Remember that all we can do is add. Even subtraction is … Read More “Chapter 6502-6 – Numbers and Math” »

(Updated February 15, 2025) Table of Contents Multi-way If Test Arrays Subroutines Self-modifying Code Multi-way If Test We will use the following code to demonstrate several features once used on the 6502. Example1.asmLoad Workspace define CHROUT $FFD2 start: jsr printres lda #$65 sec sbc #$84 beq printzero bvs printovf bmi printneg bpl printpos end: brk … Read More “Chapter 6502-5 – Beyond the Basics” »

(Updated February 15, 2025) Table of Contents Moving Data Simple Math Compare and Branch Overflow Moving Data While this is a 16-bit addressable space, we can only perform operations 8 bits at a time because our registers are also 8-bit wide. As such, working with 16-bit or 32-bit quantities means some code repetition. Let’s begin … Read More “Chapter 6502-4 – The Basics” »

(Updated February 7, 2025) Table of Contents Programs The Assembler Breakdown Features Errors Programs Let’s take a 10,000-foot tour. Our IDE has a form of compiler called an assembler. That is because it assembles the mnemonics, addresses, names, and such for a given CPU and translates it to machine code. In comparison, a compiler translates … Read More “Chapter 6502-3 – The Assembler” »

(Updated July 16, 2024) Table of Contents Physical Details Registers Instructions Addressing Modes Physical Details The MOS 6502 was originally released as a 40-pin dual-inline package (DIP-40) in both plastic and ceramic. The pins connect to locations inside the packaging and onto the CPU die with tiny filaments. Each pin represents a signal in the … Read More “Chapter 6502-2 – Basic CPU Architecture” »

(Updated January 20, 2025) Table of Contents What is and IDE? Hello World A Bigger Example What is an IDE? An Integrated Development Environment, or IDE, is typically a graphical user interface with an editor, compiler, debugger, and much more at your fingertips. During the 6502 era, the idea of having a full-featured development environment … Read More “Chapter 6502-1 – The IDE” »

(Updated February 18, 2025) Table of Contents Starting Out With Old Tech The MOS 6502 References Starting Out With Old Tech The tech we’re talking about here is the MOS 6502. Why choose an old CPU such as this? It’s a good place to begin since the CPU is so primitive that we can easily … Read More “Chapter 6502-0 – Where to Begin?” »