bit.h

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/*
 * Copyright (C) 2017 Eistec AB
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */
 
#ifndef BIT_H
#define BIT_H
 
#include <stdint.h>
#include "cpu.h"
 
#ifdef __cplusplus
extern "C" {
#endif
 
/* Define BITBAND_FUNCTIONS_PROVIDED 1 if the CPU provides its own
 * implementations for bit manipulation */
#if !BITBAND_FUNCTIONS_PROVIDED
 
#if DOXYGEN
 
#define CPU_HAS_BITBAND 1 || 0 (1 for Cortex-M3 and up, 0 for Cortex-M0)
#endif
 
#if CPU_HAS_BITBAND || DOXYGEN
/* Some MCUs provide a bitband address space for atomically accessing
 * single bits of peripheral registers, and sometimes for RAM as well */
/* Generic bit band conversion routine */
static inline volatile void *bitband_addr(volatile void *ptr, uintptr_t bit)
{
    return (volatile void *)((((uintptr_t)ptr) & 0xF0000000ul) + 0x2000000ul +
        ((((uintptr_t)ptr) & 0xFFFFFul) << 5) + (bit << 2));
}
 
static inline void bit_set32(volatile uint32_t *ptr, uint8_t bit)
{
    *((volatile uint32_t *)bitband_addr(ptr, bit)) = 1;
}
 
static inline void bit_set16(volatile uint16_t *ptr, uint8_t bit)
{
    *((volatile uint16_t *)bitband_addr(ptr, bit)) = 1;
}
 
static inline void bit_set8(volatile uint8_t *ptr, uint8_t bit)
{
    *((volatile uint8_t *)bitband_addr(ptr, bit)) = 1;
}
 
static inline void bit_clear32(volatile uint32_t *ptr, uint8_t bit)
{
    *((volatile uint32_t *)bitband_addr(ptr, bit)) = 0;
}
 
static inline void bit_clear16(volatile uint16_t *ptr, uint8_t bit)
{
    *((volatile uint16_t *)bitband_addr(ptr, bit)) = 0;
}
 
static inline void bit_clear8(volatile uint8_t *ptr, uint8_t bit)
{
    *((volatile uint8_t *)bitband_addr(ptr, bit)) = 0;
}
 
#else /* CPU_HAS_BITBAND */
/* CPU does not have bitbanding, fall back to plain C */
static inline void bit_set32(volatile uint32_t *ptr, uint8_t bit)
{
    *ptr |= (1 << (bit));
}
 
static inline void bit_set16(volatile uint16_t *ptr, uint8_t bit)
{
    *ptr |= (1 << (bit));
}
 
static inline void bit_set8(volatile uint8_t *ptr, uint8_t bit)
{
    *ptr |= (1 << (bit));
}
 
static inline void bit_clear32(volatile uint32_t *ptr, uint8_t bit)
{
    *ptr &= ~(1 << (bit));
}
 
static inline void bit_clear16(volatile uint16_t *ptr, uint8_t bit)
{
    *ptr &= ~(1 << (bit));
}
 
static inline void bit_clear8(volatile uint8_t *ptr, uint8_t bit)
{
    *ptr &= ~(1 << (bit));
}
 
#endif /* CPU_HAS_BITBAND */
 
#endif /* !BITBAND_FUNCTIONS_PROVIDED */
 
#ifdef __cplusplus
}
#endif
 
#endif /* BIT_H */