From 92b984692c3d1404a9b2520b10501be05f8ae6e9 Mon Sep 17 00:00:00 2001
From: XProger <xproger@list.ru>
Date: Sat, 22 Jan 2022 17:33:18 +0300
Subject: [PATCH] #368 improve checkROM, add vsync option, fix LineH
 rasterization

---
 src/fixed/common.h                    |  3 ++-
 src/fixed/game.h                      |  1 +
 src/fixed/inventory.h                 | 11 ++++++++
 src/platform/gba/asm/rasterizeLineH.s |  2 +-
 src/platform/gba/checkROM.cpp         | 39 ++++++++++++++++++---------
 src/platform/gba/main.cpp             |  5 ++++
 6 files changed, 46 insertions(+), 15 deletions(-)

diff --git a/src/fixed/common.h b/src/fixed/common.h
index 699ba71..36c8b55 100644
--- a/src/fixed/common.h
+++ b/src/fixed/common.h
@@ -1668,7 +1668,7 @@ struct SaveGame
     uint8 tracks[64];
 };
 
-#define SETTINGS_VER    1
+#define SETTINGS_VER    2
 #define SETTINGS_SIZE   128
 
 struct Settings
@@ -1679,6 +1679,7 @@ struct Settings
     uint8 audio_music:1;
     uint8 video_gamma:5;
     uint8 video_fps:1;
+    uint8 video_vsync:1;
 };
 
 #define FD_SET_END(x,end)   ((x) |= ((end) << 15))
diff --git a/src/fixed/game.h b/src/fixed/game.h
index 064d5ff..1357cd3 100644
--- a/src/fixed/game.h
+++ b/src/fixed/game.h
@@ -90,6 +90,7 @@ void gameInit(const char* name)
     gSettings.audio_music = 1;
     gSettings.video_gamma = 0;
     gSettings.video_fps = 1;
+    gSettings.video_vsync = 0;
     osLoadSettings();
 
     inventory.init();
diff --git a/src/fixed/inventory.h b/src/fixed/inventory.h
index 4c6d570..19d630c 100644
--- a/src/fixed/inventory.h
+++ b/src/fixed/inventory.h
@@ -90,6 +90,7 @@ enum OptionID
 // video
     OPT_ID_GAMMA = 0,
     OPT_ID_FPS = 1,
+    OPT_ID_VSYNC = 2,
 // passport
     OPT_ID_OK = 5
 };
@@ -911,6 +912,15 @@ struct Inventory
                 osSaveSettings();
             }
         }
+
+        if (optionIndex == OPT_ID_VSYNC)
+        {
+            if (gSettings.video_vsync != opt.value)
+            {
+                gSettings.video_vsync = opt.value;
+                osSaveSettings();
+            }
+        }
     }
 
     void onSound()
@@ -1231,6 +1241,7 @@ struct Inventory
             {
                 OPTION_BAR(STR_OPT_DETAIL_GAMMA, gSettings.video_gamma << 4);
                 OPTION_SWITCH(STR_OPT_DETAIL_FPS, gSettings.video_fps);
+                OPTION_SWITCH(STR_OPT_DETAIL_VSYNC, gSettings.video_vsync);
                 break;
             }
             case SLOT_SOUND:
diff --git a/src/platform/gba/asm/rasterizeLineH.s b/src/platform/gba/asm/rasterizeLineH.s
index 667b708..fab7a0f 100644
--- a/src/platform/gba/asm/rasterizeLineH.s
+++ b/src/platform/gba/asm/rasterizeLineH.s
@@ -24,7 +24,7 @@ rasterizeLineH_asm:
     strh tmp, [pixel], #2
     subs width, #1
       beq .scanline_end
-    mov pc, lr
+
 .align_right:
     tst width, #1
       beq .scanline_block_2px
diff --git a/src/platform/gba/checkROM.cpp b/src/platform/gba/checkROM.cpp
index 6b2a589..8290e8f 100644
--- a/src/platform/gba/checkROM.cpp
+++ b/src/platform/gba/checkROM.cpp
@@ -1,32 +1,33 @@
 #include <tonc.h>
 
 #define MEM_CHECK_MAGIC 14021968
+#define MEM_CHECK_SIZE  16
 
-const int ROM_MAGIC[] = {
-    MEM_CHECK_MAGIC,
+const int ROM_MAGIC[MEM_CHECK_SIZE] = {
+    MEM_CHECK_MAGIC + 0,
     MEM_CHECK_MAGIC + 1,
     MEM_CHECK_MAGIC + 2,
     MEM_CHECK_MAGIC + 3,
     MEM_CHECK_MAGIC + 4,
     MEM_CHECK_MAGIC + 5,
     MEM_CHECK_MAGIC + 6,
-    MEM_CHECK_MAGIC + 7
+    MEM_CHECK_MAGIC + 7,
+    MEM_CHECK_MAGIC + 8,
+    MEM_CHECK_MAGIC + 9,
+    MEM_CHECK_MAGIC + 10,
+    MEM_CHECK_MAGIC + 11,
+    MEM_CHECK_MAGIC + 12,
+    MEM_CHECK_MAGIC + 13,
+    MEM_CHECK_MAGIC + 14,
+    MEM_CHECK_MAGIC + 15,
 };
 
 EWRAM_CODE bool checkROM(unsigned int mask)
 {
     REG_WSCNT = mask;
 
-    for (int i = 0; i < 8; i++)
-    {
-        if (*(volatile int*)&ROM_MAGIC[i] != (MEM_CHECK_MAGIC + i))
-        {
-            REG_WSCNT = WS_ROM0_N4 | WS_ROM0_S2 | WS_PREFETCH;
-            return false;
-        }
-    }
-    
-    for (int i = 7; i >= 0; i--)
+    // check sequential read (S)
+    for (int i = 0; i < MEM_CHECK_SIZE; i++)
     {
         if (*(volatile int*)&ROM_MAGIC[i] != (MEM_CHECK_MAGIC + i))
         {
@@ -35,5 +36,17 @@ EWRAM_CODE bool checkROM(unsigned int mask)
         }
     }
 
+    // check non-sequential read (N)
+    for (int i = 0, j = MEM_CHECK_SIZE - 1; i < MEM_CHECK_SIZE; i++, j--)
+    {
+        bool L = *(volatile int*)&ROM_MAGIC[i] == (MEM_CHECK_MAGIC + i);
+        bool R = *(volatile int*)&ROM_MAGIC[j] == (MEM_CHECK_MAGIC + j);
+
+        if (L && R) continue;
+
+        REG_WSCNT = WS_ROM0_N4 | WS_ROM0_S2 | WS_PREFETCH;
+        return false;
+    }
+
     return true;
 }
\ No newline at end of file
diff --git a/src/platform/gba/main.cpp b/src/platform/gba/main.cpp
index 9aaea30..c18c9c5 100644
--- a/src/platform/gba/main.cpp
+++ b/src/platform/gba/main.cpp
@@ -596,7 +596,12 @@ int main(void)
 
         #ifdef PROFILING
             VBlankIntrWait();
+        #else
+            if (gSettings.video_vsync) {
+                VBlankIntrWait();
+            }
         #endif
+
         REG_DISPCNT = (mode ^= DCNT_PAGE);
         fb ^= VRAM_PAGE_SIZE;