kunlun/common/utils/iot_bitops.c

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Copyright(c) 2019 by Aerospace C.Power (Chongqing) Microelectronics. ALL RIGHTS RESERVED.

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be copied by any method or incorporated into another program without
the express written consent of Aerospace C.Power. This Information or any portion
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/* os shim includes */
#include "os_types.h"

/* common includes */
#include "iot_bitops.h"

/* table used for ffs and ffz operation */
const IRAM_ATTR uint8_t iot_bitops_ffs_tab[IOT_BITOPS_TAB_SIZE] = {
0, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
6, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
7, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
6, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
8, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
6, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
7, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
6, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1,
5, 1, 2, 1, 3, 1, 2, 1, 4, 1, 2, 1, 3, 1, 2, 1 };

/* table used for fls and ffz operation */
const IRAM_ATTR uint8_t iot_bitops_fls_tab[IOT_BITOPS_TAB_SIZE] = {
0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8 };

/* table used for cbs and cbz operation */
const uint8_t iot_bitops_cbs_tab[IOT_BITOPS_TAB_SIZE] = {
0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8 };

/* find the first bit set to 1 for non-zero byte */
static inline uint8_t __iot_bitops_ffs(uint8_t tmp)
{
    uint8_t b = 1;

    if (!(tmp & 0x0F)) {
        tmp >>= 4;
        b += 4;
    }
    if (!(tmp & 0x03)) {
        tmp >>= 2;
        b += 2;
    }
    if (!(tmp & 0x01)) {
        b += 1;
    }

    return b;
}

/* find the last bit set to 1 for non-zero byte */
static inline uint8_t __iot_bitops_fls(uint8_t tmp)
{
    uint8_t b = 8;

    if (!(tmp & 0xF0)) {
        tmp <<= 4;
        b -= 4;
    }
    if (!(tmp & 0xC0)) {
        tmp <<= 2;
        b -= 2;
    }
    if (!(tmp & 0x80)) {
        b -= 1;
    }

    return b;
}

/* find number of bits set to 1 for one byte */
static inline uint8_t __iot_bitops_cbs(uint8_t tmp)
{
    uint8_t b = 0;

    for (b = 0; tmp; b++) {
        /* clear the least significant bit set */
        tmp &= tmp - 1;
    }

    return b;
}

void iot_bitops_init()
{
    uint32_t i;

    for (i = 1; i < IOT_BITOPS_TAB_SIZE; i++) {
        if (iot_bitops_ffs_tab[i] != __iot_bitops_ffs((uint8_t)i))
            IOT_ASSERT(0);
    }
    for (i = 1; i < IOT_BITOPS_TAB_SIZE; i++) {
        if (iot_bitops_fls_tab[i] != __iot_bitops_fls((uint8_t)i))
            IOT_ASSERT(0);
    }
    for (i = 1; i < IOT_BITOPS_TAB_SIZE; i++) {
        if (iot_bitops_cbs_tab[i] != __iot_bitops_cbs((uint8_t)i))
            IOT_ASSERT(0);
    }
}