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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.
79 lines
1.8 KiB
Markdown
79 lines
1.8 KiB
Markdown
[← Home](../README.md) · [Devices](README.md)
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# timer.device — Timing and Delays
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## Overview
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`timer.device` provides precise timing services: delays, time-of-day, and high-resolution timestamps. It has two units:
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| Unit | Constant | Resolution | Use |
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|---|---|---|---|
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| 0 | `UNIT_MICROHZ` | ~2µs (E-clock) | Short, precise delays |
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| 1 | `UNIT_VBLANK` | ~20ms (VBlank) | Long delays, lower overhead |
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| 2 | `UNIT_ECLOCK` | CIA E-clock ticks | Highest resolution timing (OS 2.0+) |
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| 3 | `UNIT_WAITUNTIL` | absolute time | Wait until specific time (OS 2.0+) |
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| 4 | `UNIT_WAITECLOCK` | E-clock absolute | (OS 2.0+) |
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---
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## struct timeval / timerequest
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```c
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/* devices/timer.h — NDK39 */
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struct timeval {
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ULONG tv_secs; /* seconds */
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ULONG tv_micro; /* microseconds */
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};
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struct timerequest {
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struct IORequest tr_node;
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struct timeval tr_time;
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};
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```
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---
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## Simple Delay
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```c
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struct timerequest *tr = (struct timerequest *)
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CreateIORequest(port, sizeof(struct timerequest));
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OpenDevice("timer.device", UNIT_VBLANK, (struct IORequest *)tr, 0);
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tr->tr_node.io_Command = TR_ADDREQUEST;
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tr->tr_time.tv_secs = 2;
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tr->tr_time.tv_micro = 0;
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DoIO((struct IORequest *)tr); /* blocks for 2 seconds */
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CloseDevice((struct IORequest *)tr);
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DeleteIORequest((struct IORequest *)tr);
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```
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---
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## Getting Current Time
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```c
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tr->tr_node.io_Command = TR_GETSYSTIME;
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DoIO((struct IORequest *)tr);
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Printf("Time: %lu.%06lu\n", tr->tr_time.tv_secs, tr->tr_time.tv_micro);
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```
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---
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## High-Resolution Timing
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```c
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/* Read E-clock (OS 2.0+): */
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struct EClockVal eclock;
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ULONG freq = ReadEClock(&eclock); /* returns ticks/second */
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/* eclock.ev_hi, eclock.ev_lo = 64-bit tick count */
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/* Typical freq: 709379 Hz (PAL) or 715909 Hz (NTSC) */
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```
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---
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## References
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- NDK39: `devices/timer.h`
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- ADCD 2.1: timer.device autodocs
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