Taming Memory in PlayBasic with the AMA Library

August 11, 2025

 

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Taming Memory in PlayBasic with the AMA Library

When you’re writing games or tools in PlayBasic, performance isn’t just about the flashy stuff you see on screen. Behind the scenes, the way you manage memory can make or break your frame rate — and your sanity.

That’s where my Array Memory Allocation (AMA) library comes in. It’s a home-grown system that manages all your allocations inside a single, giant array. Think of it like having a huge storage unit that you divide into smaller lockers for your stuff, instead of renting a new storage unit every time you buy a box of cables.


The Problem with Dynamic Memory

PlayBasic, like most high-level languages, can allocate arrays and memory chunks on the fly. That’s fine for occasional use, but when you’re doing hundreds or thousands of small allocations in a game loop, it can become painfully slow.

The original inspiration for AMA came from some old DarkBasic code I wrote years ago. It worked, but it had some ugly performance quirks — I’m talking seconds-long delays for just a few hundred allocations. Not great when you’re trying to keep your game running at 60 FPS.


The AMA Approach

The AMA library flips the normal approach on its head:

  • One Big Array - Instead of lots of little allocations, everything lives inside a single giant array.
  • Chunk Management – The big array is treated like a heap of variable-sized blocks.
  • Minimal Shuffling – When you free memory, the space is just marked as available. If things get too fragmented, a defrag routine tidies it up.
  • This lets AMA skip the expensive “create a new array” step over and over, because the big array already exists — we’re just reassigning parts of it.

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    Why AMA still matters (even in PlayBASIC)

    You’re right that PlayBASIC supports pointers. That said, AMA remains useful for several reasons:

  • Cross-dialect portability: The AMA pattern is directly applicable to BASIC dialects that don’t support pointers, array-passing, or dynamic array creation. The article’s goal is to share ideas usable across those environments.
  • Shared container - serialization: A single heap-like container makes it easy to share, snapshot, or serialize many small data blocks as one contiguous structure.
  • Deterministic behavior and profiling: A manual allocator gives predictable allocation behavior and makes fragmentation/debug visualization simpler.
  • Centralized debug & visualization: Heatmaps, allocation stats, and defrag animations are naturally easier when all data lives in one array.
  • Performance guarantees: Even with pointer support, avoiding repeated allocations and deallocations (and garbage / VM overhead if present) can be a win — especially on constrained runtimes.

  • Seeing It in Action

    I’ve built in a color-coded heatmap so you can literally see what the allocator is doing:

  • Green = Free space
  • White = Large free chunks
  • Other colors = Allocated blocks
  • When you watch it run, you can see allocations, frees, and defrags happening in real time at 20 FPS — even with 2,000 allocations and 66MB of data in pure PlayBasic code.


    The Performance Payoff

    In testing, AMA crushed the old brute-force method:

  • Old method – ~25 seconds for 1,000 allocations (ouch)
  • AMA method – Real-time allocation & defrag without breaking a sweat
  • The magic here is using a sorted list for quick free-space lookups and only moving data when absolutely necessary. That combination delivers a big net gain without overcomplicating things.


    Next Steps

    I’m looking at squeezing even more speed out of the library by improving the copy routines — unrolling loops, copying larger words/blocks, or generating specialized copy code where beneficial. Every little gain adds up when you’re chasing performance.

    Final Thought: Memory management might not be as flashy as a new shader or sprite effect, but when your game runs smoothly, you’ll be glad you gave it some love.


    Is XOR Decryption in PlayBASIC as Fast as Assembly?

    July 07, 2025

     

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    🔍 Is XOR Decryption in PlayBASIC as Fast as Assembly?

    Every now and then, a forum question pops up that really catches my attention — and this one did just that. A PlayBASIC user recently asked:

    > "Is using XOR decryption when loading media from memory in PlayBASIC as fast as doing it in assembly?"

    At first, I was a little puzzled. Why? Because the function in question is written in assembly — it's already doing exactly what the user thought might be a separate optimization path. So, let's unpack what's really going on behind the scenes when you XOR encrypted media in memory using PlayBASIC.


    🔐 XOR Media Loading: A Quick Recap

    Years ago, PlayBASIC added support for loading media directly from memory. Earlier versions relied on external packer tools to encrypt and wrap media, but these days, you can load and decode encrypted content entirely from within your program.

    The basic workflow is:

    1. 1. Load your file into memory.
    2. 2. Call the `XORMemory` function with a key.
    3. 3. The content is decrypted and ready to use.

    You can use any XOR key you like. While XOR encryption is relatively simple and easily reversible, it’s still useful for basic protection against casual asset ripping.


    🧠 What Happens Internally?

    When you call `XORMemory`, PlayBASIC doesn’t interpret the data — it pushes the work down to the engine’s internal rendering system. Specifically, it uses the XOR ink mode inside the `Box` drawing function.

    This function writes color data onto a surface by XOR’ing it with the existing pixels. Here’s what makes it cool: that surface isn’t necessarily a visible screen — it's just treated as raw memory.

    To decrypt, the engine:

  • Creates a temporary 32-bit image buffer (must be 32-bit to handle raw data correctly).
  • Loads the encrypted file data into that buffer.
  • Applies the XOR key using the `Box` command in XOR mode.
  • Copies the result back to memory.
  • That’s it.


    💥 But Is It Fast?

    Yes. Very fast — because under the hood, this process is powered by raw MMX assembly.

    When the engine detects MMX support, it uses MMX instructions to process 64 bits (two 32-bit pixels) at a time:

  • Data is loaded into MMX registers.
  • XOR is performed at the hardware level.
  • Results are written back immediately.
  • Here’s the inner loop in plain terms:

  • Load two pixels from memory.
  • Load XOR key into a register.
  • XOR them.
  • Write them back.
  • Repeat in a tight loop.
  • We’re talking near cycle-per-pixel speeds here — hardware-level performance. If MMX isn't available, it gracefully falls back to optimized C code. Either way, you're getting a performance-optimized routine.


    🕰 Legacy Notes

    Older machines or systems using 16-bit display modes may encounter issues unless you force a 32-bit surface. That’s why the engine explicitly creates a 32-bit buffer in the decoding routine — it ensures consistent behavior across different environments.

    Also worth noting: drawing directly to the screen (especially in older systems where the screen buffer lives in VRAM) would be very slow due to the read/write overhead. But modern systems (e.g., Windows 10/11) emulate these surfaces in system memory, allowing direct blending without penalty.


    ✅ Final Thoughts

    So, to answer the original question:

    Yes — XOR decryption in PlayBASIC is as fast as it can be. It’s literally done in machine code.

    This is just one example of how PlayBASIC leans on low-level optimizations to make higher-level features accessible and fast. You get the convenience of a BASIC command, but the performance of assembly behind the scenes.


    Got more technical questions?

    Join the conversation on the forums, or check out the help files for more info about ink modes, memory banks, and low-level drawing operations.


    Tags:

    `#PlayBASIC` `#GameDev` `#Encryption` `#Assembly` `#MMX` `#XOR` `#RetroCoding` `#Performance`

    BASIC Isn't Dead. It Just Grew Up.

    June 01, 2025

     

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    1. BASIC Isn't Dead. It Just Grew Up.

    If you learned to program in the 80s or 90s, chances are your first line of code looked something like this:

    PRINT "Hello, World!"
    

    To many, BASIC feels like a relic of computing’s early days—an outdated teaching tool overshadowed by modern languages like Python or JavaScript. But that assumption couldn't be more wrong. BASIC never disappeared. It diversified. It evolved. And today, it lives on in a wide range of powerful, practical dialects still being used to build games, web tools, business systems, and more.

    2. What Made BASIC Great Then Still Matters Today

    BASIC was designed to be accessible. Its name stands for Beginner's All-purpose Symbolic Instruction Code, and its creators wanted students to focus on learning to solve problems, not memorizing syntax. That simplicity, that clarity, is what makes BASIC surprisingly relevant even now.

    Today's developers value code that is readable, quick to write, and easy to maintain. Sound familiar? That’s the same philosophy behind modern favorites like Python, Lua, and even aspects of Swift. BASIC got there decades earlier.

    3. Visual Basic: The Face Everyone Recognizes

    No conversation about BASIC is complete without mentioning Visual Basic (VB). Introduced by Microsoft in the early 90s, VB turned BASIC into a powerhouse for Windows development. Its visual form designer and event-driven model made it the go-to language for building business applications and internal tools.

    Even today, VB.NET is still supported in Visual Studio, and VBA (Visual Basic for Applications) remains deeply embedded in Microsoft Office, driving automation and macros across the business world.

    But here’s the key point: Visual Basic is just one dialect. BASIC’s legacy didn’t stop with VB—it blossomed into a wide ecosystem of modern tools, many of which continue to be actively developed.

    4. Beyond VB: The Modern BASIC Landscape

    🎮 Game Development

  • PlayBASIC: Designed for 2D game development with beginner-friendly syntax and graphics built-in.
  • BlitzBASIC / Blitz3D / BlitzMax: Known for real-time game development. Still loved by retro game coders.
  • DarkBASIC: Created to simplify 3D game creation on Windows.
  • ⚙️ General Purpose / Desktop

  • PureBASIC: Cross-platform, compiled language with full support for GUIs, DLLs, and multimedia.
  • FreeBASIC: A modern take on QBASIC with low-level access, C-like performance, and inline assembly support.
  • Oxygen BASIC: Lightweight and powerful, compiling directly to machine code.
  • 📱 Mobile and Cross-Platform

  • B4X: Formerly Basic4Android, B4X now targets Android, iOS, and desktop platforms with VB-like syntax.
  • 🌐 Web, Scripting & Automation

  • VBA: Still widely used in Excel and Access to automate reports, calculations, and workflows.
  • BasicAnywhere: A lightweight BASIC interpreter that runs in the browser.
  • 5. BASIC vs. Python: Different Names, Shared Philosophy

    Many developers praise Python for its simplicity, readability, and gentle learning curve. But that exact spirit was BASIC's mission from day one. The syntax and philosophy of BASIC have more in common with Python than most realize:

    REM BASIC
    PRINT "Hello, World!"
    
    # Python
    print("Hello, World!")
    

    Both prioritize clarity over cleverness. Both are great for beginners and prototyping. BASIC simply got there first.

    6. Why BASIC Still Deserves a Place at the Table

    Modern BASICs aren't just toys. They support features you'd expect in any serious language:

  • Compiled executables
  • GUI frameworks
  • Graphics and sound
  • Cross-platform support
  • Integration with system APIs
  • In many cases, these tools are faster to learn and deploy than bloated stacks involving multiple frameworks and languages. That makes BASIC a compelling choice for hobbyists, indie developers, and even small businesses looking for quick, effective solutions.

    7. Final Thoughts: BASIC Isn’t Just Nostalgia—It’s a Toolset That Works

    The myth that BASIC is obsolete is just that—a myth. While it may not dominate headlines, BASIC continues to evolve, empower, and enable. It never stopped being useful. It never stopped being fun.

    If you're a Python fan, or just want to create something without jumping through endless setup hoops, explore modern BASICs. There’s a whole ecosystem waiting for rediscovery.


    Where to Try Modern BASICs:

  • FreeBASIC
  • PureBASIC
  • PlayBASIC
  • B4X
  • QB64
  • BlitzMax NG
  • Oxygen BASIC

  • BASIC didn’t fade away. It just grew up quietly. And it’s still here—faster, friendlier, and more flexible than ever.