1 files changed, 54 insertions, 0 deletions
diff --git a/src/Dolphin/si/SISamplingRate.c b/src/Dolphin/si/SISamplingRate.c
new file mode 100644
index 0000000..c9b96ca
--- /dev/null
+++ b/src/Dolphin/si/SISamplingRate.c
@@ -0,0 +1,54 @@
+#include "dolphin/sipriv.h"
+#include "dolphin/vi.h"
+#pragma dont_inline on
+static u32 SamplingRate;
+
+typedef struct XY {
+  u16 line;
+  u8 count;
+} XY;
+
+static XY XYNTSC[12] = {
+    {263 - 17, 2}, {15, 18}, {30, 9}, {44, 6},  {52, 5},  {65, 4},
+    {87, 3},       {87, 3}, {87, 3}, {131, 2}, {131, 2}, {131, 2},
+};
+
+static XY XYPAL[12] = {
+    {313 - 17, 2}, {15, 21}, {29, 11}, {45, 7},  {52, 6},  {63, 5},
+    {78, 4},       {104, 3}, {104, 3}, {104, 3}, {104, 3}, {156, 2},
+};
+
+void SISetSamplingRate(u32 msec) {
+  XY* xy;
+  BOOL enabled;
+
+  if (msec > 11) {
+    msec = 11;
+  }
+
+  enabled = OSDisableInterrupts();
+
+  SamplingRate = msec;
+
+  switch (VIGetTvFormat()) {
+  case VI_NTSC:
+  case VI_MPAL:
+  case VI_EURGB60:
+    xy = XYNTSC;
+    break;
+  case VI_PAL:
+    xy = XYPAL;
+    break;
+  default:
+    OSReport("SISetSamplingRate: unknown TV format. Use default.");
+    msec = 0;
+    xy = XYNTSC;
+    break;
+  }
+
+  SISetXY((__VIRegs[54] & 1 ? 2u : 1u) * xy[msec].line, xy[msec].count);
+  OSRestoreInterrupts(enabled);
+}
+
+void SIRefreshSamplingRate() { SISetSamplingRate(SamplingRate); }
+#pragma dont_inline reset