misc.hpp

Go to the documentation of this file.

/*
 * SPDX-FileCopyrightText: 2024 M5Stack Technology CO LTD
 *
 * SPDX-License-Identifier: MIT
 */
#ifndef M5_UTILITY_MISC_HPP
#define M5_UTILITY_MISC_HPP
 
#include <cstdint>
 
namespace m5 {
namespace utility {
 
inline bool isValidI2CAddress(const uint16_t addr)
{
    if (addr <= 0x7F) {  // 7 bit
        return (addr >= 0x08 && addr <= 0x77);
    }
    return addr <= 0x3FF;  // 10 bit
}
 
inline uint8_t reverseBitOrder(const uint8_t u8)
{
#if defined(__clang__) && 0
#pragma message "Using clang builtin"
    return __builtin_bitreverse8(u8);
#else
    uint8_t v{u8};
    v = ((v & 0xF0) >> 4) | ((v & 0x0F) << 4);
    v = ((v & 0xCC) >> 2) | ((v & 0x33) << 2);
    v = ((v & 0xAA) >> 1) | ((v & 0x55) << 1);
    return v;
#endif
}
 
inline uint16_t reverseBitOrder(const uint16_t u16)
{
#if defined(__clang__) && 0
#pragma message "Using clang builtin"
    return __builtin_bitreverse16(u16);
#else
    uint16_t v{u16};
    v = ((v & 0xFF00) >> 8) | ((v & 0x00FF) << 8);
    v = ((v & 0xF0F0) >> 4) | ((v & 0x0F0F) << 4);
    v = ((v & 0xCCCC) >> 2) | ((v & 0x3333) << 2);
    v = ((v & 0xAAAA) >> 1) | ((v & 0x5555) << 1);
    return v;
#endif
}
 
}  // namespace utility
}  // namespace m5
#endif