mirror of
https://github.com/alfishe/amiga-bootcamp.git
synced 2026-06-13 00:26:28 +00:00
21751c0025
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.
104 lines
3.1 KiB
Markdown
104 lines
3.1 KiB
Markdown
[← Home](../README.md) · [Boot Sequence](README.md)
|
||
|
||
# Kickstart Initialisation — ROM Scan, ExecBase, Resident Modules
|
||
|
||
## Overview
|
||
|
||
After hardware init, the Kickstart ROM creates `ExecBase` and scans for **resident modules** — the OS components compiled into ROM. This process builds the entire OS kernel from tagged structures embedded in the ROM image.
|
||
|
||
---
|
||
|
||
## ExecBase Creation
|
||
|
||
1. Allocate ExecBase structure at a known address (end of Chip RAM)
|
||
2. Initialise memory lists, library list, device list, resource list
|
||
3. Store ExecBase pointer at **address `$000004`** — the global `SysBase`
|
||
4. Initialise the Supervisor stack, interrupt vectors, trap vectors
|
||
|
||
```
|
||
After this step:
|
||
*(ULONG *)4 == ExecBase pointer
|
||
SysBase->LibNode.lib_Version == Kickstart version
|
||
```
|
||
|
||
---
|
||
|
||
## Resident Module Scan
|
||
|
||
The ROM scanner searches for **RomTag** markers (`$4AFC`) throughout the ROM address range:
|
||
|
||
```c
|
||
struct Resident {
|
||
UWORD rt_MatchWord; /* $4AFC — magic marker */
|
||
struct Resident *rt_MatchTag; /* pointer to self (verification) */
|
||
APTR rt_EndSkip; /* skip past this address */
|
||
UBYTE rt_Flags; /* RTF_COLDSTART, RTF_SINGLETASK, etc. */
|
||
UBYTE rt_Version; /* version number */
|
||
UBYTE rt_Type; /* NT_LIBRARY, NT_DEVICE, NT_RESOURCE */
|
||
BYTE rt_Pri; /* init priority (higher = earlier) */
|
||
char *rt_Name; /* module name */
|
||
char *rt_IdString; /* version string */
|
||
APTR rt_Init; /* init function or auto-init table */
|
||
};
|
||
```
|
||
|
||
### Scan Algorithm
|
||
|
||
```
|
||
for addr in ROM_START to ROM_END step 2:
|
||
if *(UWORD *)addr == $4AFC:
|
||
tag = (struct Resident *)addr
|
||
if tag->rt_MatchTag == tag: /* self-pointer validates */
|
||
add to resident list
|
||
addr = tag->rt_EndSkip /* skip past module */
|
||
```
|
||
|
||
---
|
||
|
||
## Initialisation Phases
|
||
|
||
Residents are initialised in **priority order** within each phase:
|
||
|
||
### Phase 1: RTF_COLDSTART (flags bit 0)
|
||
|
||
Called during cold boot, single-tasking (no scheduler yet):
|
||
|
||
| Priority | Module | Description |
|
||
|---|---|---|
|
||
| 126 | `exec.library` | Core kernel |
|
||
| 120 | `expansion.library` | AutoConfig Zorro boards |
|
||
| 105 | `68040.library` | CPU trap handlers (if present) |
|
||
| 100 | `utility.library` | Tag/hook support |
|
||
| 70 | `graphics.library` | Display init |
|
||
| 50 | `layers.library` | Clipping layers |
|
||
| 50 | `intuition.library` | GUI subsystem |
|
||
| 40 | `timer.device` | Timing services |
|
||
| 30 | `keyboard.device` | Keyboard |
|
||
| 20 | `input.device` | Input event merging |
|
||
| 10 | `trackdisk.device` | Floppy |
|
||
| −50 | `dos.library` | AmigaDOS file system |
|
||
| −120 | `ramlib` | Disk-based library/device loader |
|
||
|
||
### Phase 2: RTF_SINGLETASK
|
||
|
||
Runs after all COLDSTART modules but before multitasking begins. Used by strap (bootstrap) module.
|
||
|
||
### Phase 3: RTF_AFTERDOS
|
||
|
||
Runs after DOS is available. External disk-based modules.
|
||
|
||
---
|
||
|
||
## After Resident Init
|
||
|
||
1. Multitasking enabled (scheduler starts)
|
||
2. `dos.library` creates initial CLI process
|
||
3. Boot task launches `strap` → reads boot block from DF0: or boot device
|
||
4. Control passes to `startup-sequence`
|
||
|
||
---
|
||
|
||
## References
|
||
|
||
- NDK39: `exec/resident.h`
|
||
- RKRM: Resident modules chapter
|