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.

11_libraries/rexxsyslib.md

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+[← Home](../README.md) · [Libraries](README.md)
+
+# rexxsyslib.library — ARexx Interface
+
+## Overview
+
+ARexx is the Amiga's built-in macro/scripting language (based on REXX). `rexxsyslib.library` provides APIs for hosting ARexx ports, sending commands, and receiving results.
+
+---
+
+## Adding an ARexx Port
+
+```c
+struct MsgPort *arexxPort = CreateMsgPort();
+arexxPort->mp_Node.ln_Name = "MYAPP";
+arexxPort->mp_Node.ln_Pri  = 0;
+AddPort(arexxPort);
+
+/* In event loop, check for ARexx messages: */
+struct RexxMsg *rmsg;
+while ((rmsg = (struct RexxMsg *)GetMsg(arexxPort))) {
+    STRPTR cmd = ARG0(rmsg);  /* the command string */
+    /* Parse and execute command... */
+    rmsg->rm_Result1 = 0;    /* RC = 0 (success) */
+    rmsg->rm_Result2 = 0;
+    ReplyMsg((struct Message *)rmsg);
+}
+
+RemPort(arexxPort);
+DeleteMsgPort(arexxPort);
+```
+
+---
+
+## Sending ARexx Commands
+
+```c
+struct MsgPort *replyPort = CreateMsgPort();
+struct RexxMsg *rmsg = CreateRexxMsg(replyPort, NULL, NULL);
+rmsg->rm_Args[0] = CreateArgstring("QUIT", 4);
+rmsg->rm_Action  = RXCOMM;
+
+struct MsgPort *target = FindPort("TARGETAPP");
+if (target) {
+    PutMsg(target, &rmsg->rm_Node);
+    WaitPort(replyPort);
+    GetMsg(replyPort);
+    /* rmsg->rm_Result1 = return code */
+}
+
+DeleteArgstring(rmsg->rm_Args[0]);
+DeleteRexxMsg(rmsg);
+DeleteMsgPort(replyPort);
+```
+
+---
+
+## References
+
+- NDK39: `rexx/storage.h`, `rexx/rxslib.h`