firmware: improve rounding during Hz -> mHz conversion

wntrblm · Feb 10, 2024 · 5881a90 · 5881a90
1 parent 3426d2d
commit 5881a90
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Showing 2 changed files with 3 additions and 2 deletions.
diff --git a/firmware/src/lib/gem_math.h b/firmware/src/lib/gem_math.h
@@ -104,5 +104,5 @@ inline static __attribute__((always_inline)) fix16_t gem_voct_to_frequency(fix16
 inline static uint64_t __attribute__((always_inline)) gem_frequency_to_millihertz_f16_u64(fix16_t freq_hz) {
     uint32_t freq_whole = freq_hz >> 16;
     uint32_t freq_frac = freq_hz & 0xFFFF;
-    return (freq_whole * 100) + (freq_frac * 100 / 0xFFFF);
+    return (freq_whole * 100) + ((freq_frac * 100 + 0x8000) >> 16);
 }
diff --git a/firmware/tests/test_oscillator.c b/firmware/tests/test_oscillator.c
@@ -13,6 +13,7 @@
 #include "gem_test.h"
 #include "gem_pulseout.h"
 #include "wntr_uint12.h"
+#include <inttypes.h>
 #include <math.h>
 
 const struct WntrErrorCorrection error_correction = {.offset = F16(0), .gain = F16(1)};
@@ -485,7 +486,7 @@ TEST_CASE_BEGIN(cv_pitch_period_conversion)
         print_f16(cv);
         printf(" V freq = ");
         print_f16(freq);
-        printf(" Hz millihertz = %llu mHz period = %u, roundtrip = %f Hz, diff = %f ppm", mhertz, period, roundtrip, diff);
+        printf(" Hz millihertz = %" PRIu64 " mHz period = %" PRIu32 ", roundtrip = %f Hz, diff = %f ppm", mhertz, period, roundtrip, diff);
     }
     printf("\n");
 TEST_CASE_END