esp-idf/components/hal/hal_utils.c

195 lines
6.8 KiB
C

/*
* SPDX-FileCopyrightText: 2023-2024 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "hal/hal_utils.h"
#include "hal/assert.h"
#ifndef BIT
#define BIT(n) (1UL << (n))
#endif
#ifndef BIT_MASK
#define BIT_MASK(n) (BIT(n) - 1)
#endif
__attribute__((always_inline))
static inline uint32_t _sub_abs(uint32_t a, uint32_t b)
{
return a > b ? a - b : b - a;
}
uint32_t hal_utils_calc_clk_div_frac_fast(const hal_utils_clk_info_t *clk_info, hal_utils_clk_div_t *clk_div)
{
HAL_ASSERT(clk_info->max_fract > 2);
uint32_t div_denom = 2;
uint32_t div_numer = 0;
uint32_t div_integ = clk_info->src_freq_hz / clk_info->exp_freq_hz;
uint32_t freq_error = clk_info->src_freq_hz % clk_info->exp_freq_hz;
// fractional divider
if (freq_error) {
// Carry bit if the decimal is greater than 1.0 - 1.0 / ((max_fract - 1) * 2)
if (freq_error < clk_info->exp_freq_hz - clk_info->exp_freq_hz / (clk_info->max_fract - 1) * 2) {
// Calculate the Greatest Common Divisor, time complexity O(log n)
uint32_t gcd = hal_utils_gcd(clk_info->exp_freq_hz, freq_error);
// divide by the Greatest Common Divisor to get the accurate fraction before normalization
div_denom = clk_info->exp_freq_hz / gcd;
div_numer = freq_error / gcd;
// normalize div_denom and div_numer
uint32_t d = div_denom / clk_info->max_fract + 1;
// divide by the normalization coefficient to get the denominator and numerator within range of clk_info->max_fract
div_denom /= d;
div_numer /= d;
} else {
div_integ++;
}
}
// If the expect frequency is too high or too low to satisfy the integral division range, failed and return 0
if (div_integ < clk_info->min_integ || div_integ >= clk_info->max_integ || div_integ == 0) {
return 0;
}
// Assign result
clk_div->integer = div_integ;
clk_div->denominator = div_denom;
clk_div->numerator = div_numer;
// Return the actual frequency
if (div_numer) {
uint32_t temp = div_integ * div_denom + div_numer;
return (uint32_t)(((uint64_t)clk_info->src_freq_hz * div_denom + temp / 2) / temp);
}
return clk_info->src_freq_hz / div_integ;
}
uint32_t hal_utils_calc_clk_div_frac_accurate(const hal_utils_clk_info_t *clk_info, hal_utils_clk_div_t *clk_div)
{
HAL_ASSERT(clk_info->max_fract > 2);
uint32_t div_denom = 2;
uint32_t div_numer = 0;
uint32_t div_integ = clk_info->src_freq_hz / clk_info->exp_freq_hz;
uint32_t freq_error = clk_info->src_freq_hz % clk_info->exp_freq_hz;
if (freq_error) {
// Carry bit if the decimal is greater than 1.0 - 1.0 / ((max_fract - 1) * 2)
if (freq_error < clk_info->exp_freq_hz - clk_info->exp_freq_hz / (clk_info->max_fract - 1) * 2) {
// Search the closest fraction, time complexity O(n)
for (uint32_t sub = 0, a = 2, b = 0, min = UINT32_MAX; min && a < clk_info->max_fract; a++) {
b = (a * freq_error + clk_info->exp_freq_hz / 2) / clk_info->exp_freq_hz;
sub = _sub_abs(clk_info->exp_freq_hz * b, freq_error * a);
if (sub < min) {
div_denom = a;
div_numer = b;
min = sub;
}
}
} else {
div_integ++;
}
}
// If the expect frequency is too high or too low to satisfy the integral division range, failed and return 0
if (div_integ < clk_info->min_integ || div_integ >= clk_info->max_integ || div_integ == 0) {
return 0;
}
// Assign result
clk_div->integer = div_integ;
clk_div->denominator = div_denom;
clk_div->numerator = div_numer;
// Return the actual frequency
if (div_numer) {
uint32_t temp = div_integ * div_denom + div_numer;
return (uint32_t)(((uint64_t)clk_info->src_freq_hz * div_denom + temp / 2) / temp);
}
return clk_info->src_freq_hz / div_integ;
}
uint32_t hal_utils_calc_clk_div_integer(const hal_utils_clk_info_t *clk_info, uint32_t *int_div)
{
uint32_t div_integ = clk_info->src_freq_hz / clk_info->exp_freq_hz;
uint32_t freq_error = clk_info->src_freq_hz % clk_info->exp_freq_hz;
/* If there is error and always round up,
Or, do the normal rounding and error >= (src/n + src/(n+1)) / 2,
then carry the bit */
if ((freq_error && clk_info->round_opt == HAL_DIV_ROUND_UP) || (clk_info->round_opt == HAL_DIV_ROUND &&
(freq_error >= clk_info->src_freq_hz / (2 * div_integ * (div_integ + 1))))) {
div_integ++;
}
/* Check the integral division whether in range [min_integ, max_integ) */
/* If the result is less than the minimum, set the division to the minimum but return 0 */
if (div_integ < clk_info->min_integ) {
*int_div = clk_info->min_integ;
return 0;
}
/* if the result is greater or equal to the maximum , set the division to the maximum but return 0 */
if (div_integ >= clk_info->max_integ) {
*int_div = clk_info->max_integ - 1;
return 0;
}
// Assign result
*int_div = div_integ;
// Return the actual frequency
return clk_info->src_freq_hz / div_integ;
}
typedef union {
struct {
uint32_t mantissa: 23;
uint32_t exponent: 8;
uint32_t sign: 1;
};
uint32_t val;
} hal_utils_ieee754_float_t;
int hal_utils_float_to_fixed_point_32b(float flt, const hal_utils_fixed_point_t *fp_cfg, uint32_t *fp_out)
{
int ret = 0;
uint32_t output = 0;
const hal_utils_ieee754_float_t *f = (const hal_utils_ieee754_float_t *)&flt;
if (fp_cfg->int_bit + fp_cfg->frac_bit > 31) {
// Not supported
return -3;
}
if (f->val == 0) { // Zero case
*fp_out = 0;
return 0;
}
if (f->exponent != 0xFF) { // Normal case
int real_exp = (int)f->exponent - 127;
uint32_t real_mant = f->mantissa | BIT(23); // Add the hidden bit
// Overflow check
if (real_exp >= (int)fp_cfg->int_bit) {
ret = -1;
}
// Determine sign
output |= f->sign << (fp_cfg->int_bit + fp_cfg->frac_bit);
// Determine integer and fraction part
int shift = 23 - fp_cfg->frac_bit - real_exp;
output |= shift >= 0 ? real_mant >> shift : real_mant << -shift;
} else {
if (f->mantissa && f->mantissa < BIT(23) - 1) { // NaN (Not-a-Number) case
return -2;
} else { // Infinity or Largest Number case
output = f->sign ? ~(uint32_t)0 : BIT(31) - 1;
ret = -1;
}
}
if (ret != 0 && fp_cfg->saturation) {
*fp_out = (f->sign << (fp_cfg->int_bit + fp_cfg->frac_bit)) |
(BIT_MASK(fp_cfg->int_bit + fp_cfg->frac_bit));
} else {
*fp_out = output;
}
return ret;
}