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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

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← Home · Libraries

Math Libraries — Floating Point

Overview

AmigaOS provides multiple math libraries for floating-point operations. The 68000 has no FPU, so all math is done in software unless a 68881/68882/68040/68060 FPU is present.

Library Stack

Library	Format	Description
`mathffp.library`	FFP (Motorola Fast Floating Point)	Original Amiga format (32-bit)
`mathieeesingbas.library`	IEEE 754 single (32-bit)	IEEE single precision
`mathieeedoubbas.library`	IEEE 754 double (64-bit)	IEEE double precision
`mathtrans.library`	FFP	Transcendental functions (sin, cos, sqrt)
`mathieeesingtrans.library`	IEEE single	IEEE single transcendentals
`mathieeedoubtrans.library`	IEEE double	IEEE double transcendentals

FFP Format

Motorola FFP is NOT IEEE 754:

Bits 31–8: 24-bit mantissa (normalised, implicit 1.xxx)
Bits  7–1: 7-bit exponent (excess-64)
Bit     0: sign (0=positive, 1=negative)

Using IEEE Math

struct Library *MathIeeeSingBasBase =
    OpenLibrary("mathieeesingbas.library", 0);

float a = 3.14f;
float b = 2.0f;
float c = IEEESPMul(a, b);  /* 6.28 */
float d = IEEESPAdd(a, b);  /* 5.14 */
float e = IEEESPDiv(a, b);  /* 1.57 */

CloseLibrary(MathIeeeSingBasBase);

68881/68882 FPU

When an FPU is present, the math libraries are replaced with ROM patches that use native FPU instructions. The application code is identical — the library transparently switches to hardware.

if (SysBase->AttnFlags & AFF_68881) {
    /* 68881/68882 FPU present */
}
if (SysBase->AttnFlags & AFF_FPU40) {
    /* 68040 internal FPU */
}

References

NDK39: libraries/mathffp.h, libraries/mathieeesp.h

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