docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections

Comprehensive technical documentation covering:
- Hardware: OCS/ECS/AGA custom chip registers, Copper & Blitter deep dives
- Boot sequence: cold boot through startup-sequence
- Binary format: HUNK executable spec, relocation, debug info
- Linking & ABI: .fd files, LVO tables, register calling conventions
- Exec kernel: tasks, interrupts, memory, signals, semaphores
- AmigaDOS: file I/O, FFS/OFS layout, CLI/Shell scripting
- Graphics: planar bitmaps, Copper programming, HAM/EHB modes
- Intuition: screens, windows, IDCMP, BOOPSI
- Devices: trackdisk, SCSI, serial, timer, audio, keyboard
- Libraries: utility, expansion, IFFParse, locale, ARexx
- Networking: bsdsocket API, SANA-II, TCP/IP stack comparison
- Toolchain: GCC, vasm/vlink, SAS/C, NDK, debugging
- Reverse engineering: IDA/Ghidra setup, compiler fingerprints, case studies
- CPU & MMU: 68040/060 emulation libs, PMMU, cache management
- Driver development: SANA-II, Picasso96/RTG, AHI audio

All files include breadcrumb navigation. No local paths or proprietary content.

10_devices/gameport.md

@@ -0,0 +1,64 @@
+[← Home](../README.md) · [Devices](README.md)
+
+# gameport.device — Joystick and Mouse
+
+## Overview
+
+`gameport.device` reads joystick and mouse ports (active on port 1 for joystick, port 0 for mouse). Uses CIA and custom chip registers.
+
+---
+
+## Controller Types
+
+```c
+/* devices/gameport.h */
+#define GPCT_ALLOCATED   -1   /* port is allocated */
+#define GPCT_NOCONTROLLER 0   /* nothing connected */
+#define GPCT_MOUSE       1   /* mouse */
+#define GPCT_RELJOYSTICK 2   /* relative joystick (proportional) */
+#define GPCT_ABSJOYSTICK 3   /* absolute joystick */
+```
+
+---
+
+## Reading a Joystick
+
+```c
+struct IOStdReq *gp = CreateStdIO(port);
+OpenDevice("gameport.device", 1, (struct IORequest *)gp, 0);
+
+/* Set controller type: */
+UBYTE type = GPCT_ABSJOYSTICK;
+gp->io_Command = GPD_SETCTYPE;
+gp->io_Data    = &type;
+gp->io_Length  = 1;
+DoIO((struct IORequest *)gp);
+
+/* Set trigger conditions: */
+struct GamePortTrigger trigger = {
+    GPTF_UPKEYS | GPTF_DOWNKEYS,  /* report buttons */
+    10000,   /* X delta timeout */
+    10000,   /* Y delta timeout */
+    1, 1     /* X/Y delta threshold */
+};
+gp->io_Command = GPD_SETTRIGGER;
+gp->io_Data    = &trigger;
+gp->io_Length  = sizeof(trigger);
+DoIO((struct IORequest *)gp);
+
+/* Read events: */
+struct InputEvent ie;
+gp->io_Command = GPD_READEVENT;
+gp->io_Data    = &ie;
+gp->io_Length  = sizeof(ie);
+DoIO((struct IORequest *)gp);
+/* ie.ie_Code, ie.ie_position.ie_xy give button/direction */
+
+CloseDevice((struct IORequest *)gp);
+```
+
+---
+
+## References
+
+- NDK39: `devices/gameport.h`