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moved isqrt to filter.h

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This commit is contained in:
Alessandro Mauri 2026-05-15 21:31:21 +02:00
parent 288aa914e9
commit 546178c700
2 changed files with 21 additions and 20 deletions
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21
fw/filter.h
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@ -2,6 +2,7 @@
#define _FILTER_H
#include <stdint.h>
#include <assert.h>
#define MIN(a, b) ((a) < (b) ? (a) : (b))
@ -23,4 +24,24 @@ static_assert(-4 >> 1 == -2, ">> doesn't do sign extension");
#define I16_FP_EMA_K8(x, s) (int16_t)((((int32_t)(x)<<8) - (x) + (s)) >> 8)
#define I16_FP_EMA_K16(x, s) (int16_t)((((int32_t)(x)<<16) - (x) + (s)) >> 16)
// Integer square root (binary search)
// https://en.wikipedia.org/wiki/Integer_square_root
static inline uint16_t isqrt(uint32_t x)
{
uint16_t l = 0; // lower bound of the square root
uint16_t r = x + 1; // upper bound of the square root
while (l != r - 1) {
uint32_t m = (l + r) / 2; // midpoint to test
if (m * m <= x) {
l = m;
} else {
r = m;
}
}
return l;
}
#endif // _FILTER_H

20
fw/main.c
View File

@ -345,26 +345,6 @@ static inline void pwm_set(uint16_t pulse_width)
}
// Integer square root (binary search)
// https://en.wikipedia.org/wiki/Integer_square_root
static inline uint16_t isqrt(uint32_t x)
{
uint16_t l = 0; // lower bound of the square root
uint16_t r = x + 1; // upper bound of the square root
while (l != r - 1) {
uint32_t m = (l + r) / 2; // midpoint to test
if (m * m <= x) {
l = m;
} else {
r = m;
}
}
return l;
}
// Input: temperature difference
// Output: duty-cycle 0-max_duty
uint16_t pid(int16_t delta, int16_t max_duty)