altos: Perform time comparisons using 16-bit arithmetic to handle wrap
[fw/altos] / src / kernel / ao_kalman.c
index 9aea1f14762f6139d9fb8dce932b98a6c946068d..d401a3c8ff5bd04a88c7dea0216d53abcd145589 100644 (file)
@@ -3,7 +3,8 @@
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; version 2 of the License.
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
 #include "ao_sample.h"
 #include "ao_kalman.h"
 
+static __pdata ao_k_t          ao_k_height;
+static __pdata ao_k_t          ao_k_speed;
+static __pdata ao_k_t          ao_k_accel;
 
-static __pdata int32_t         ao_k_height;
-static __pdata int32_t         ao_k_speed;
-static __pdata int32_t         ao_k_accel;
+#define AO_K_STEP_100          to_fix_v(0.01)
+#define AO_K_STEP_2_2_100      to_fix_v(0.00005)
 
-#define AO_K_STEP_100          to_fix16(0.01)
-#define AO_K_STEP_2_2_100      to_fix16(0.00005)
+#define AO_K_STEP_10           to_fix_v(0.1)
+#define AO_K_STEP_2_2_10       to_fix_v(0.005)
 
-#define AO_K_STEP_10           to_fix16(0.1)
-#define AO_K_STEP_2_2_10       to_fix16(0.005)
+#define AO_K_STEP_1            to_fix_v(1)
+#define AO_K_STEP_2_2_1                to_fix_v(0.5)
 
-#define AO_K_STEP_1            to_fix16(1)
-#define AO_K_STEP_2_2_1                to_fix16(0.5)
+__pdata ao_v_t                 ao_height;
+__pdata ao_v_t                 ao_speed;
+__pdata ao_v_t                 ao_accel;
+__xdata ao_v_t                 ao_max_height;
+static __pdata ao_k_t          ao_avg_height_scaled;
+__xdata ao_v_t                 ao_avg_height;
 
-__pdata int16_t                        ao_height;
-__pdata int16_t                        ao_speed;
-__pdata int16_t                        ao_accel;
-__xdata int16_t                        ao_max_height;
-static __pdata int32_t         ao_avg_height_scaled;
-__xdata int16_t                        ao_avg_height;
-
-__pdata int16_t                        ao_error_h;
-__pdata int16_t                        ao_error_h_sq_avg;
+__pdata ao_v_t                 ao_error_h;
+__pdata ao_v_t                 ao_error_h_sq_avg;
 
 #if HAS_ACCEL
-__pdata int16_t                        ao_error_a;
+__pdata ao_v_t                 ao_error_a;
 #endif
 
 static void
 ao_kalman_predict(void)
 {
 #ifdef AO_FLIGHT_TEST
-       if (ao_sample_tick - ao_sample_prev_tick > 50) {
-               ao_k_height += ((int32_t) ao_speed * AO_K_STEP_1 +
-                               (int32_t) ao_accel * AO_K_STEP_2_2_1) >> 4;
-               ao_k_speed += (int32_t) ao_accel * AO_K_STEP_1;
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
+               ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_1 +
+                               (ao_k_t) ao_accel * AO_K_STEP_2_2_1) >> 4;
+               ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_1;
 
                return;
        }
-       if (ao_sample_tick - ao_sample_prev_tick > 5) {
-               ao_k_height += ((int32_t) ao_speed * AO_K_STEP_10 +
-                               (int32_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
-               ao_k_speed += (int32_t) ao_accel * AO_K_STEP_10;
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
+               ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_10 +
+                               (ao_k_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
+               ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_10;
 
                return;
        }
        if (ao_flight_debug) {
                printf ("predict speed %g + (%g * %g) = %g\n",
                        ao_k_speed / (65536.0 * 16.0), ao_accel / 16.0, AO_K_STEP_100 / 65536.0,
-                       (ao_k_speed + (int32_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
+                       (ao_k_speed + (ao_k_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
        }
 #endif
-       ao_k_height += ((int32_t) ao_speed * AO_K_STEP_100 +
-                       (int32_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
-       ao_k_speed += (int32_t) ao_accel * AO_K_STEP_100;
+       ao_k_height += ((ao_k_t) ao_speed * AO_K_STEP_100 +
+                       (ao_k_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
+       ao_k_speed += (ao_k_t) ao_accel * AO_K_STEP_100;
 }
 
 static void
 ao_kalman_err_height(void)
 {
-       int16_t e;
-       int16_t height_distrust;
+       ao_v_t  e;
+       ao_v_t height_distrust;
 #if HAS_ACCEL
-       int16_t speed_distrust;
+       ao_v_t  speed_distrust;
 #endif
 
-       ao_error_h = ao_sample_height - (int16_t) (ao_k_height >> 16);
+       ao_error_h = ao_sample_height - (ao_v_t) (ao_k_height >> 16);
 
        e = ao_error_h;
        if (e < 0)
@@ -123,7 +123,7 @@ ao_kalman_err_height(void)
 #endif
                if (height_distrust > 0x100)
                        height_distrust = 0x100;
-               ao_error_h = (int16_t) (((int32_t) ao_error_h * (0x100 - height_distrust)) >> 8);
+               ao_error_h = (ao_v_t) (((ao_k_t) ao_error_h * (0x100 - height_distrust)) >> 8);
 #ifdef AO_FLIGHT_TEST
                if (ao_flight_debug) {
                        printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
@@ -141,22 +141,22 @@ ao_kalman_correct_baro(void)
 {
        ao_kalman_err_height();
 #ifdef AO_FLIGHT_TEST
-       if (ao_sample_tick - ao_sample_prev_tick > 50) {
-               ao_k_height += (int32_t) AO_BARO_K0_1 * ao_error_h;
-               ao_k_speed  += (int32_t) AO_BARO_K1_1 * ao_error_h;
-               ao_k_accel  += (int32_t) AO_BARO_K2_1 * ao_error_h;
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
+               ao_k_height += (ao_k_t) AO_BARO_K0_1 * ao_error_h;
+               ao_k_speed  += (ao_k_t) AO_BARO_K1_1 * ao_error_h;
+               ao_k_accel  += (ao_k_t) AO_BARO_K2_1 * ao_error_h;
                return;
        }
-       if (ao_sample_tick - ao_sample_prev_tick > 5) {
-               ao_k_height += (int32_t) AO_BARO_K0_10 * ao_error_h;
-               ao_k_speed  += (int32_t) AO_BARO_K1_10 * ao_error_h;
-               ao_k_accel  += (int32_t) AO_BARO_K2_10 * ao_error_h;
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
+               ao_k_height += (ao_k_t) AO_BARO_K0_10 * ao_error_h;
+               ao_k_speed  += (ao_k_t) AO_BARO_K1_10 * ao_error_h;
+               ao_k_accel  += (ao_k_t) AO_BARO_K2_10 * ao_error_h;
                return;
        }
 #endif
-       ao_k_height += (int32_t) AO_BARO_K0_100 * ao_error_h;
-       ao_k_speed  += (int32_t) AO_BARO_K1_100 * ao_error_h;
-       ao_k_accel  += (int32_t) AO_BARO_K2_100 * ao_error_h;
+       ao_k_height += (ao_k_t) AO_BARO_K0_100 * ao_error_h;
+       ao_k_speed  += (ao_k_t) AO_BARO_K1_100 * ao_error_h;
+       ao_k_accel  += (ao_k_t) AO_BARO_K2_100 * ao_error_h;
 }
 
 #if HAS_ACCEL
@@ -164,7 +164,7 @@ ao_kalman_correct_baro(void)
 static void
 ao_kalman_err_accel(void)
 {
-       int32_t accel;
+       ao_k_t  accel;
 
        accel = (ao_config.accel_plus_g - ao_sample_accel) * ao_accel_scale;
 
@@ -180,46 +180,46 @@ ao_kalman_correct_both(void)
        ao_kalman_err_accel();
 
 #ifdef AO_FLIGHT_TEST
-       if (ao_sample_tick - ao_sample_prev_tick > 50) {
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50) {
                if (ao_flight_debug) {
                        printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
                                ao_k_speed / (65536.0 * 16.0),
                                (double) ao_error_h, AO_BOTH_K10_1 / 65536.0,
                                (double) ao_error_a, AO_BOTH_K11_1 / 65536.0,
                                (ao_k_speed +
-                                (int32_t) AO_BOTH_K10_1 * ao_error_h +
-                                (int32_t) AO_BOTH_K11_1 * ao_error_a) / (65536.0 * 16.0));
+                                (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
+                                (ao_k_t) AO_BOTH_K11_1 * ao_error_a) / (65536.0 * 16.0));
                }
                ao_k_height +=
-                       (int32_t) AO_BOTH_K00_1 * ao_error_h +
-                       (int32_t) AO_BOTH_K01_1 * ao_error_a;
+                       (ao_k_t) AO_BOTH_K00_1 * ao_error_h +
+                       (ao_k_t) AO_BOTH_K01_1 * ao_error_a;
                ao_k_speed +=
-                       (int32_t) AO_BOTH_K10_1 * ao_error_h +
-                       (int32_t) AO_BOTH_K11_1 * ao_error_a;
+                       (ao_k_t) AO_BOTH_K10_1 * ao_error_h +
+                       (ao_k_t) AO_BOTH_K11_1 * ao_error_a;
                ao_k_accel +=
-                       (int32_t) AO_BOTH_K20_1 * ao_error_h +
-                       (int32_t) AO_BOTH_K21_1 * ao_error_a;
+                       (ao_k_t) AO_BOTH_K20_1 * ao_error_h +
+                       (ao_k_t) AO_BOTH_K21_1 * ao_error_a;
                return;
        }
-       if (ao_sample_tick - ao_sample_prev_tick > 5) {
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
                if (ao_flight_debug) {
                        printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
                                ao_k_speed / (65536.0 * 16.0),
                                (double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
                                (double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
                                (ao_k_speed +
-                                (int32_t) AO_BOTH_K10_10 * ao_error_h +
-                                (int32_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
+                                (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
+                                (ao_k_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
                }
                ao_k_height +=
-                       (int32_t) AO_BOTH_K00_10 * ao_error_h +
-                       (int32_t) AO_BOTH_K01_10 * ao_error_a;
+                       (ao_k_t) AO_BOTH_K00_10 * ao_error_h +
+                       (ao_k_t) AO_BOTH_K01_10 * ao_error_a;
                ao_k_speed +=
-                       (int32_t) AO_BOTH_K10_10 * ao_error_h +
-                       (int32_t) AO_BOTH_K11_10 * ao_error_a;
+                       (ao_k_t) AO_BOTH_K10_10 * ao_error_h +
+                       (ao_k_t) AO_BOTH_K11_10 * ao_error_a;
                ao_k_accel +=
-                       (int32_t) AO_BOTH_K20_10 * ao_error_h +
-                       (int32_t) AO_BOTH_K21_10 * ao_error_a;
+                       (ao_k_t) AO_BOTH_K20_10 * ao_error_h +
+                       (ao_k_t) AO_BOTH_K21_10 * ao_error_a;
                return;
        }
        if (ao_flight_debug) {
@@ -228,19 +228,19 @@ ao_kalman_correct_both(void)
                        (double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
                        (double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
                        (ao_k_speed +
-                        (int32_t) AO_BOTH_K10_100 * ao_error_h +
-                        (int32_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
+                        (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
+                        (ao_k_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
        }
 #endif
        ao_k_height +=
-               (int32_t) AO_BOTH_K00_100 * ao_error_h +
-               (int32_t) AO_BOTH_K01_100 * ao_error_a;
+               (ao_k_t) AO_BOTH_K00_100 * ao_error_h +
+               (ao_k_t) AO_BOTH_K01_100 * ao_error_a;
        ao_k_speed +=
-               (int32_t) AO_BOTH_K10_100 * ao_error_h +
-               (int32_t) AO_BOTH_K11_100 * ao_error_a;
+               (ao_k_t) AO_BOTH_K10_100 * ao_error_h +
+               (ao_k_t) AO_BOTH_K11_100 * ao_error_a;
        ao_k_accel +=
-               (int32_t) AO_BOTH_K20_100 * ao_error_h +
-               (int32_t) AO_BOTH_K21_100 * ao_error_a;
+               (ao_k_t) AO_BOTH_K20_100 * ao_error_h +
+               (ao_k_t) AO_BOTH_K21_100 * ao_error_a;
 }
 
 #else
@@ -250,15 +250,15 @@ ao_kalman_correct_accel(void)
 {
        ao_kalman_err_accel();
 
-       if (ao_sample_tick - ao_sample_prev_tick > 5) {
-               ao_k_height +=(int32_t) AO_ACCEL_K0_10 * ao_error_a;
-               ao_k_speed  += (int32_t) AO_ACCEL_K1_10 * ao_error_a;
-               ao_k_accel  += (int32_t) AO_ACCEL_K2_10 * ao_error_a;
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5) {
+               ao_k_height +=(ao_k_t) AO_ACCEL_K0_10 * ao_error_a;
+               ao_k_speed  += (ao_k_t) AO_ACCEL_K1_10 * ao_error_a;
+               ao_k_accel  += (ao_k_t) AO_ACCEL_K2_10 * ao_error_a;
                return;
        }
-       ao_k_height += (int32_t) AO_ACCEL_K0_100 * ao_error_a;
-       ao_k_speed  += (int32_t) AO_ACCEL_K1_100 * ao_error_a;
-       ao_k_accel  += (int32_t) AO_ACCEL_K2_100 * ao_error_a;
+       ao_k_height += (ao_k_t) AO_ACCEL_K0_100 * ao_error_a;
+       ao_k_speed  += (ao_k_t) AO_ACCEL_K1_100 * ao_error_a;
+       ao_k_accel  += (ao_k_t) AO_ACCEL_K2_100 * ao_error_a;
 }
 
 #endif /* else FORCE_ACCEL */
@@ -285,9 +285,9 @@ ao_kalman(void)
                ao_max_height = ao_height;
        ao_avg_height_scaled = ao_avg_height_scaled - ao_avg_height + ao_sample_height;
 #ifdef AO_FLIGHT_TEST
-       if (ao_sample_tick - ao_sample_prev_tick > 50)
+       if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 50)
                ao_avg_height = (ao_avg_height_scaled + 1) >> 1;
-       else if (ao_sample_tick - ao_sample_prev_tick > 5)
+       else if ((int16_t) (ao_sample_tick - ao_sample_prev_tick) > 5)
                ao_avg_height = (ao_avg_height_scaled + 7) >> 4;
        else 
 #endif