If you're not prepared to be wrong, you'll never come up with anything original. – Sir Ken Robinson
(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 November 23, 2024) FactorialIter.javaOpen in JDoodle public class FactorialIter { public static int fact(int n) { int prod = 1; if ( n < 0 ) throw new IllegalArgumentException("Value cannot be negative."); for (int i = n; i > 1; i–) prod = prod * i; return prod; } public static void main(String [] … Read More “TEST JDoodle” »
(Updated November 18, 2024) Printing.asmLoad Workspace define CHROUT $ffd2 ldx #0 ; set index to zero print: lda words,x ; load a letter from words beq done ; if it’s the zero, we’re done jsr CHROUT ; print the character inx ; increment the index bne print ; keep printing done: brk ; end! ; … Read More “TEST 6502” »
(Updated July 10, 2024) Table of contents Overview Certificates Requesting Certificates Cipher Suites File Formats Configurations VICE Overview Overview The secure exchange of information is essential to protecting vital data sent over networks. Here, we will look at the details related to PKI and SSL. Public key infrastructure (PKI) governs the issuance of digital certificates … Read More “PKI and SSL” »
(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?” »
(Updated November 20, 2024) Table of contents Overview BASIC History BASIC Statement Structure BASIC Language BASIC Constructs Afterward VICE Overview The BASIC (Beginner’s All-purpose Symbolic Instruction Code) language was created by John Kemeny and Thomas Kurtz at Dartmouth in 1964. It was a simple, unstructured language that was reasonably easy to learn. BASIC was prevalent … Read More “C64 BASIC (in about an hour)” »