working dos vga writes!

Common/Snd/bitcrsh.h

@@ -0,0 +1,29 @@
+/*
+    Simple fixed point bitcrash.
+    https://github.com/schollz/fpfx
+*/
+
+#ifndef COM_SND_BITCRSH_H
+#define COM_SND_BITCRSH_H
+
+#include "../fix.h"
+#include <stdint.h>
+
+struct com_snd_bitcrsh {
+  uint8_t bits;   /* How much to trim when triggered. */
+  uint8_t reduce; /* Every Nth sample frame. */
+};
+
+static void com_snd_bitcrsh_process(Bitcrush *bitcrush, int32_t *buf,
+                                    unsigned int nr_samples) {
+  for (int i = 0; i < nr_samples; i++) {
+    if (i % bitcrush->reduce == 0) {
+      // bitcrush fixedpoint
+      buf[i] = buf[i] >> (16 - bitcrush->bits) << (16 - bitcrush->bits);
+    } else {
+      buf[i] = buf[i - 1];
+    }
+  }
+}
+
+#endif