mirror of https://github.com/alfishe/amiga-bootcamp.git synced 2026-06-13 00:26:28 +00:00

History

Ilia Sharin 21751c0025 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.		2026-04-23 12:17:35 -04:00
..
chip_ram_expansion.md	docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections	2026-04-23 12:17:35 -04:00
chipset_ecs.md	docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections	2026-04-23 12:17:35 -04:00
ecs_registers_delta.md	docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections	2026-04-23 12:17:35 -04:00
gary_gayle.md	docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections	2026-04-23 12:17:35 -04:00
productivity_modes.md	docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections	2026-04-23 12:17:35 -04:00
README.md	docs(amiga): complete AmigaOS 3.1/3.2 developer reference — 172 files across 17 sections	2026-04-23 12:17:35 -04:00

README.md

← Home · Hardware

ECS Chipset — A600 / A3000 / A500+

Overview

The Enhanced Chip Set (ECS) is a significant revision of OCS, shipping from 1990 onward. It adds 2 MB Chip RAM addressing, programmable display timing, and extended registers while maintaining full backward compatibility with OCS software.

Chip Summary

Chip	Part	Changes from OCS
Super Agnus	MOS 8372A	Addresses 2 MB Chip RAM, extended DMA window
ECS Denise	MOS 8373	BPLCON3, border blank, programmable sync
Paula	MOS 8364	Unchanged

File	Topic
chipset_ecs.md	Super Agnus and ECS Denise internals
ecs_registers_delta.md	New/changed registers vs OCS
productivity_modes.md	Multiscan/productivity display modes
gary_gayle.md	Gary (A3000) and Gayle (A600) chips: IDE, PCMCIA
chip_ram_expansion.md	2 MB Chip RAM with Super Agnus

ECS vs OCS — Key Differences

Feature	OCS	ECS
Max Chip RAM	1 MB (Fat Agnus)	2 MB (Super Agnus)
Display sync	Fixed NTSC/PAL	BEAMCON0 — programmable
Bitplane scroll	4-bit (BPLCON1)	Extended (ECS Denise)
Border blank	No	BPLCON3 border control
Hires sprites	No	ECS Denise extended sprite control
DMA window	Smaller	Extended: wider bitplane fetch

Identifying ECS at Runtime

#include <exec/execbase.h>

struct ExecBase *SysBase = *((struct ExecBase **)4);
/* AttnFlags does not directly identify chipset */

/* Use graphics.library GfxBase->ChipRevBits0 */
#include <graphics/gfxbase.h>
struct GfxBase *GfxBase = (struct GfxBase *)OpenLibrary("graphics.library", 0);
if (GfxBase->ChipRevBits0 & GFXB_BIG_BLITTER) { /* ECS+ */ }
if (GfxBase->ChipRevBits0 & GFXB_HR_AGNUS)    { /* Super Agnus */ }
if (GfxBase->ChipRevBits0 & GFXB_HR_DENISE)   { /* ECS Denise */ }

Machines Using ECS

Model	Notes
A3000	Super Agnus + ECS Denise; 68030; SCSI; Zorro III
A500+	Super Agnus (1 MB variant); ECS Denise; no IDE
A600	Super Agnus (1 MB variant); ECS Denise; Gayle; IDE; PCMCIA
A2000 (late)	Some late rev boards shipped with ECS chips

References

ADCD 2.1 Hardware Manual — ECS extension chapters
NDK39: graphics/gfxbase.h — ChipRevBits0 flags
Amiga Hardware Reference Manual 3rd ed. — ECS appendix