Gleb Koval
c5e41db9b0
- load_avg, recent_cpu, priority calculations - reduce frac bits to 14 - ignore thread_set_priority when BSD enabled
96 lines
1.9 KiB
C
96 lines
1.9 KiB
C
#include <stdint.h>
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#ifndef FIXED_POINT_H
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#define FIXED_POINT_H
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typedef struct
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{
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int32_t raw;
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} fp32_t;
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/* Fixed Point Arithmetic bit count constants */
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#define NUM_FRAC_BITS 14
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#define NUM_INT_BITS (31 - NUM_FRAC_BITS)
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#define CONVERSION_CONST (1 << NUM_FRAC_BITS) /* f = 2^q, (2^20) */
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/* Fixed Point Arithmetic conversion operations */
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/* Converts an integer n to a fixed point number */
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inline fp32_t
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int_to_fp (int32_t n)
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{
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return (fp32_t){ n * CONVERSION_CONST };
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}
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/* Handles conversion of fixed point to integer. First version truncates, second one rounds */
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inline int32_t
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fp_floor (fp32_t x)
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{
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return x.raw / CONVERSION_CONST;
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}
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inline int32_t
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fp_round (fp32_t x)
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{
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if (x.raw >= 0)
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return (x.raw + CONVERSION_CONST / 2) / CONVERSION_CONST;
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else
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return (x.raw - CONVERSION_CONST / 2) / CONVERSION_CONST;
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}
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/* Add two fixed points */
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inline fp32_t
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fp_add (fp32_t x, fp32_t y)
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{
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return (fp32_t){ x.raw + y.raw };
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}
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/* Subtract two fixed points */
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inline fp32_t
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fp_sub (fp32_t x, fp32_t y)
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{
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return (fp32_t){ x.raw - y.raw };
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}
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/* Add fixed point to integer */
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inline fp32_t
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fp_add_int (fp32_t x, int32_t n)
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{
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return (fp32_t){ x.raw + n * CONVERSION_CONST };
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}
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/* Subtract integer from fixed point */
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inline fp32_t
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fp_sub_int (fp32_t x, int32_t n)
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{
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return (fp32_t){ x.raw - n * CONVERSION_CONST };
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}
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/* Multiple two fixed points */
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inline fp32_t
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fp_mul (fp32_t x, fp32_t y)
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{
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return (fp32_t){ ((int64_t)x.raw) * y.raw / CONVERSION_CONST };
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}
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/* Divide two fixed points */
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inline fp32_t
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fp_div (fp32_t x, fp32_t y)
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{
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return (fp32_t){ ((int64_t)x.raw) * CONVERSION_CONST / y.raw };
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}
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/* Multiply fixed point and integer */
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inline fp32_t
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fp_mul_int (fp32_t x, int32_t n)
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{
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return (fp32_t){ x.raw * n };
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}
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/* Divide fixed point by integer */
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inline fp32_t
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fp_div_int (fp32_t x, int32_t n)
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{
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return (fp32_t){ x.raw / n };
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}
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#endif //FIXED_POINT_H
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