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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.
74 lines
2 KiB
Markdown
74 lines
2 KiB
Markdown
[← Home](../README.md) · [Graphics](README.md)
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# Display Modes — Display Database, ModeID, Monitor Specs
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## Overview
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OS 3.0+ provides a **display database** that abstracts monitor/chipset capabilities. Applications query available modes by `ModeID` rather than hardcoding `HIRES`/`LACE` flags.
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---
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## ModeID Format
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A ModeID is a ULONG:
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```
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bits 31–16: Monitor ID
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bits 15–0: Mode within that monitor
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```
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| ModeID | Name | Resolution |
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|---|---|---|
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| `$00000000` | LORES | 320×256 (PAL) / 320×200 (NTSC) |
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| `$00008000` | HIRES | 640×256/200 |
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| `$00000004` | LORES-LACE | 320×512/400 |
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| `$00008004` | HIRES-LACE | 640×512/400 |
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| `$00080000` | SUPERHIRES | 1280×256 (ECS+) |
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| `$00080004` | SUPERHIRES-LACE | 1280×512 |
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| `$00039000` | DBLPAL-LORES | 320×256 (AGA scan-doubled) |
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| `$00039004` | DBLPAL-HIRES | 640×256 (AGA) |
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| `$00011000` | DBLNTSC-LORES | 320×200 (AGA) |
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---
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## Querying the Display Database
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```c
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/* graphics.library 39+ */
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ULONG modeID = INVALID_ID;
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struct DisplayInfo di;
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struct DimensionInfo dims;
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while ((modeID = NextDisplayInfo(modeID)) != INVALID_ID) {
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if (GetDisplayInfoData(NULL, (UBYTE *)&di, sizeof(di),
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DTAG_DISP, modeID)) {
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if (GetDisplayInfoData(NULL, (UBYTE *)&dims, sizeof(dims),
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DTAG_DIMS, modeID)) {
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Printf("ModeID $%08lx: %ldx%ld, %ld colours\n",
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modeID,
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dims.Nominal.MaxX - dims.Nominal.MinX + 1,
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dims.Nominal.MaxY - dims.Nominal.MinY + 1,
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1 << di.NotAvailable ? 0 : dims.MaxDepth);
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}
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}
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}
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```
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---
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## Best Mode Selection
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```c
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ULONG bestMode = BestModeIDA((struct TagItem[]){
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{ BIDTAG_NominalWidth, 640 },
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{ BIDTAG_NominalHeight, 480 },
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{ BIDTAG_Depth, 8 },
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{ TAG_DONE, 0 }
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});
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```
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---
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## References
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- NDK39: `graphics/displayinfo.h`, `graphics/modeid.h`
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- ADCD 2.1: `NextDisplayInfo`, `GetDisplayInfoData`, `BestModeIDA`
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