121 lines
4.8 KiB
C
121 lines
4.8 KiB
C
/**
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* @file FR_Defs.h - type definitions used in Fixed-Radix math lib
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*
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* @copy Copyright (C) <2001-2026> <M. A. Chatterjee>
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* @author M A Chatterjee <deftio [at] deftio [dot] com>
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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*
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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*
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* 3. This notice may not be removed or altered from any source
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* distribution.
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*
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*/
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#ifndef __FR_Platform_Defs_H__
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#define __FR_Platform_Defs_H__
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/*
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* Fixed-width integer typedefs.
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*
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* Prefer C99 <stdint.h> when available (gcc, clang, MSVC, IAR, Keil, sdcc,
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* MSP430-gcc, AVR-gcc, RISC-V, ARM toolchains). For bare-metal toolchains
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* or pre-C99 compilers that lack <stdint.h>, define FR_NO_STDINT before
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* including this header and the types are provided via sizeof()-based
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* fallback definitions that cover the common 8/16/32/64-bit layouts.
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*/
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#ifndef FR_NO_STDINT
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#include <stdint.h>
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#else
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/* ---- fallback: no <stdint.h> ------------------------------------ */
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/* Works on any toolchain where char=8, short=16, int/long=32 bits,
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* which covers virtually all embedded targets (AVR, MSP430, ARM,
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* 68HC11, 68k, PPC, RISC-V, Xtensa, x86). Adjust if your platform
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* differs.
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*/
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typedef unsigned char uint8_t;
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typedef signed char int8_t;
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typedef unsigned short uint16_t;
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typedef signed short int16_t;
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#if defined(__AVR__) || defined(__MSP430__) || defined(__m68hc1x__)
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/* On these targets int is 16-bit; use long for 32-bit */
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typedef unsigned long uint32_t;
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typedef signed long int32_t;
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#else
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typedef unsigned int uint32_t;
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typedef signed int int32_t;
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#endif
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/* 64-bit: available on most 32-bit+ GCC targets via long long */
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typedef unsigned long long uint64_t;
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typedef signed long long int64_t;
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#endif /* FR_NO_STDINT */
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/*
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* Arduino's USBAPI.h typedefs u8 and u16 as unsigned char / unsigned short.
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* On AVR, uint8_t/uint16_t resolve to unsigned int types, which are the same
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* width but different C++ types — causing a redefinition error. Skip those
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* two typedefs when building in an Arduino environment; the Arduino-provided
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* types are the same width and work identically.
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*
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* The guard checks __cplusplus too because Arduino.h (which pulls in
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* USBAPI.h) is only auto-included in .ino/.cpp translation units.
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* Plain-C files (.c) compiled by the Arduino build system need our
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* typedefs even though the ARDUINO macro is defined for them.
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*/
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#if defined(ARDUINO) && defined(__cplusplus)
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/* Arduino C++ TU — USBAPI.h already provides u8 and u16 */
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#else
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typedef uint8_t u8;
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typedef uint16_t u16;
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#endif
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typedef int8_t s8;
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typedef int16_t s16;
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typedef uint32_t u32;
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typedef int32_t s32;
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typedef uint64_t u64;
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typedef int64_t s64;
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typedef short FR_bool;
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#define FR_SWAP_BYTES(x) (((x >> 8) & 0xff) | ((x << 8) & 0xff00))
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/*=======================================================
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* Sentinel values for math errors.
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*
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* Functions that can hit a domain error (sqrt of negative, log of <=0, etc.)
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* return one of these sentinels rather than raising an error code. Callers
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* that care can check `result == FR_DOMAIN_ERROR` before using the value.
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*
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* FR_OVERFLOW_POS and FR_OVERFLOW_NEG are the saturating-overflow values
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* returned by FR_FixMulSat / FR_FixAddSat etc. They are deliberately the
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* extremes of s32 so that they compare correctly under signed comparison.
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*
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* Note: FR_DOMAIN_ERROR equals INT32_MIN (the same value as FR_OVERFLOW_NEG
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* would naturally be), so a single check `result <= FR_OVERFLOW_NEG` cannot
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* distinguish "saturating-negative-overflow" from "domain error". In
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* practice the two never occur in the same call: saturating ops never go
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* to a domain-error state, and domain-error ops never saturate. The names
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* exist to make caller intent self-documenting.
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*/
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#define FR_DOMAIN_ERROR ((s32)0x80000000) /* INT32_MIN: e.g. sqrt(<0) */
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#define FR_OVERFLOW_POS ((s32)0x7fffffff) /* INT32_MAX: e.g. FR_FixMulSat + */
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#define FR_OVERFLOW_NEG ((s32)0x80000000) /* INT32_MIN: e.g. FR_FixMulSat - */
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#define FR_FALSE (0)
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#define FR_TRUE (!FR_FALSE)
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#endif /* __FR_Platform_Defs_H__ */
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