From 8b27dbe623c2d38b447bdfa9c2b16c0ba5183887 Mon Sep 17 00:00:00 2001
From: StapleButter <thetotalworm@gmail.com>
Date: Sat, 13 Sep 2014 17:01:20 +0200
Subject: [PATCH] * Make the GSP event handler signal events in the right order
 (essential for proper PICA200 sync) * Add some comments about the GSP events
 (based on my observations, may not be right)

---
 libctru/include/3ds/services/gsp.h | 6 +++---
 libctru/source/services/gsp.c      | 8 ++++----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/libctru/include/3ds/services/gsp.h b/libctru/include/3ds/services/gsp.h
index f7ddfc2..d324b9a 100644
--- a/libctru/include/3ds/services/gsp.h
+++ b/libctru/include/3ds/services/gsp.h
@@ -37,12 +37,12 @@ typedef struct
 
 typedef enum
 {
-	GSPEVENT_PSC0 = 0,
+	GSPEVENT_PSC0 = 0,	// memory fill completed
 	GSPEVENT_PSC1,
 	GSPEVENT_VBlank0,
 	GSPEVENT_VBlank1,
-	GSPEVENT_PPF,
-	GSPEVENT_P3D,
+	GSPEVENT_PPF,		// display transfer finished
+	GSPEVENT_P3D,		// command list processing finished
 	GSPEVENT_DMA,
 
 	GSPEVENT_MAX, // used to know how many events there are
diff --git a/libctru/source/services/gsp.c b/libctru/source/services/gsp.c
index 7c64019..24fff1d 100644
--- a/libctru/source/services/gsp.c
+++ b/libctru/source/services/gsp.c
@@ -85,15 +85,15 @@ void gspEventThreadMain(u32 arg)
 		svcClearEvent(gspEvent);
 
 		int count = gspEventData[1];
-		int last = gspEventData[0] + count;
+		int cur = gspEventData[0];
+		int last = cur + count;
 		while (last >= 0x34) last -= 0x34;
-		int cur = last;
 		int i;
 		for (i = 0; i < count; i ++)
 		{
 			int curEvt = gspEventData[0xC + cur];
-			cur --;
-			if (cur < 0) cur += 0x34;
+			cur ++;
+			if (cur >= 0x34) cur -= 0x34;
 			if (curEvt >= GSPEVENT_MAX) continue;
 			svcSignalEvent(gspEvents[curEvt]);
 		}