1 files changed, 38 insertions, 0 deletions
diff --git a/src/shared/math.c b/src/shared/math.c
new file mode 100644
index 0000000..900cced
--- /dev/null
+++ b/src/shared/math.c
@@ -0,0 +1,38 @@
+#include "shared/math.h"
+
+uint8_t sintable[256] = {
+    128, 131, 134, 137, 140, 143, 146, 149, 152, 155, 158, 162, 165, 167, 170,
+    173, 176, 179, 182, 185, 188, 190, 193, 196, 198, 201, 203, 206, 208, 211,
+    213, 215, 218, 220, 222, 224, 226, 228, 230, 232, 234, 235, 237, 238, 240,
+    241, 243, 244, 245, 246, 248, 249, 250, 250, 251, 252, 253, 253, 254, 254,
+    254, 255, 255, 255, 255, 255, 255, 255, 254, 254, 254, 253, 253, 252, 251,
+    250, 250, 249, 248, 246, 245, 244, 243, 241, 240, 238, 237, 235, 234, 232,
+    230, 228, 226, 224, 222, 220, 218, 215, 213, 211, 208, 206, 203, 201, 198,
+    196, 193, 190, 188, 185, 182, 179, 176, 173, 170, 167, 165, 162, 158, 155,
+    152, 149, 146, 143, 140, 137, 134, 131, 128, 124, 121, 118, 115, 112, 109,
+    106, 103, 100, 97,  93,  90,  88,  85,  82,  79,  76,  73,  70,  67,  65,
+    62,  59,  57,  54,  52,  49,  47,  44,  42,  40,  37,  35,  33,  31,  29,
+    27,  25,  23,  21,  20,  18,  17,  15,  14,  12,  11,  10,  9,   7,   6,
+    5,   5,   4,   3,   2,   2,   1,   1,   1,   0,   0,   0,   0,   0,   0,
+    0,   1,   1,   1,   2,   2,   3,   4,   5,   5,   6,   7,   9,   10,  11,
+    12,  14,  15,  17,  18,  20,  21,  23,  25,  27,  29,  31,  33,  35,  37,
+    40,  42,  44,  47,  49,  52,  54,  57,  59,  62,  65,  67,  70,  73,  76,
+    79,  82,  85,  88,  90,  93,  97,  100, 103, 106, 109, 112, 115, 118, 121,
+    124,
+};
+
+uint8_t byte_sin(uint8_t n)
+{
+  return sintable[n];
+}
+
+uint8_t amp(uint8_t in, uint8_t n)
+{
+  uint32_t out = in;
+
+  for (int i = 0; i < n; ++i) {
+    out = (out * in) / 256;
+  }
+
+  return min(out, 255);
+}