siziolibv3: Siz's I/O library v3

1. Introduction

The IOLibV3 is a modular hardware detection and IRq loader framework for the Commodore 264 series of computers. Main goal of development was to create a totally asynchronous loader system that can be used together with any IRq handlers and is compatible with as many drive types as possible.

Loader features

• file name based (first two characters of name are checked)
  • you can load files in any order
  • you can load files from an SD2IEC directory natively
• IRq loader
  • you can interrupt loading any time
• uses serial protocol based on number of serial drives detected
  • TODO: currently only the multi-drive protocol is implemented
  • for parallel and TCBM interfaces the number of drives is not important and not used
• DOS compatible, sector based (NOT A TRACKLOADER)
  • this ensures compatiblity with non-GCR drives
  • but it's not so fast

2. Modules

All functionality of the library is divided into modules. All modules can be included/excluded using compilation options. List of modules:

1. Hardware detection (mandatory)
2. Detailed status report of detected hardware (for debugging purposes)
3. Video standard detection
4. Memory size detection
5. Sound source detection
6. Loader (includes drive type detection)
7. On-the-fly Exomizer decruncher

2.1 Hardware detection

Executes all included detection modules.

2.2 Detection status report

All hardware detection modules can report what they found via standard chrout printing to screen (lower case characters). This can be totally switched off to avoid printing the obvious and to save memory and disk space.

2.3 memory size detection

Detects available RAM size:

• 16k
• 32k
• 64k
• 128k (Hannes/Csory)
• 256k (Hannes/Csory)
• 512k (Hannes/Csory)
• 1024k (Hannes/Csory)
• 2048k (Hannes only)
• 4096k (Hannes only)

2.4 Video standard detection

Based on TED control register #2 ($ff07) bit 6. (Yeah, it's simple, mostly for reporting)

2.5 Sound source detection

Detects if a SID card is plugged in, the SID chip type (6581/8580) and if the card is an NST Audio Extension (BSz SID Card). Also detects the presens of AY extension (DIGIMUZ) and tries to detect FM emulation of SideKick.

2.6 Loader

Detects devices connected to the computer from #4 to #31. First executes a drive ROM read and tries to identify the drive type. If that fails it will execute a UI command to get the initialization status message from the drive and uses that to look up drive type.

Drive types detected:

• Commodore 1540
• Commodore 1541
• Commodore 1541C
• Commodore 1541-II
• Commodore 1551
• Commodore 1570
• Commodore 1571
• Commodore 1581
• RF501C
• SD2IEC

After the drive type is identified it will detected the interface used to connect the drive to the computer in the following order

• TCBM (1551)
• parallel (154*)
• serial (154*, 157*, 158*, RF501C, SD2IEC)

2.7 Exomizer decruncher

There is a module for unpacking Exomizer 3.0.1 packed files on-the-fly. To use this feature you have to start exomizer with mem -f options.

3. Usage

3.1 Self-built

In the included IOLibV3Test.asm source you can see an example how to use the library. Basically you have to create an initialization part that detects hardware and installs loader. In this init part you have to include two sources:

• iolib_def.inc: definitions for the library. This is required for all programs where you want to use the library
• iolib.inc: the library itself. It can be compiled to any memory location You also have to define which modules needed. For example:

.namespace iolib {
	#define	prtstatus
	#define need_video_detect
	#define need_memory_detect
	#define need_sound_detect
	#define need_loader
	#define need_exodecrunch
}

You have to call two functions:

• iolib.detect to do hardware detection
• iolib.init to initialize the loader. This will install the loader from $fc00-$fcff with some variables from $fbfb-fbff. If you use exomizer decruncher it will occupy $fa70-$fbef.

After that you only have to do the following in your parts:

• include iolib_def.inc
• call iolib.load or iolib.decrunch with first character of file name in XR and second one in YR
• quit loader: set both X and Y to 0 and call iolib.load. It will report a load error and quits drive side code. NOTE This does not work with SD2IEC G.I. Joe loader (stock SD2IEC firmware).

For variables set by detection check the contents of iolib_def.inc.

3.2 Pre-compiled

There is an INIT.PRG in the repository which can be used to start your software. All you have to do is put this as the first file in the directory and the program you want to load must be named II and that must be compressed with exomizer mem -f. After load/decompress a jmp $100d will be made.

4. Memory used

Address	Usage
$02/$03	Init only (you can safely use it after iolib.init)
$9e/$9f	Non-exomizer load pointer (you can use it but it will be destroyed during non-exomizer loads)
$a7-$a9, $ae/$af, $fc-$ff	Exomizer decruncher only. Free if you don't use exomizer
$b7	Serial load shift area. Not used on non-serial drives
$fa70-$fbef	Exomizer decruncher resident part
$fbfb-$fbff	Work area
$fc00-$fcff	Loader resident part
$ff40-$ffdc	Exomizer decruncher work area. Will be overwritten during Exomizer load.