From 9fe27e257939224d5a85975dee39f63f50b7e3dc Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Sat, 10 Dec 2011 23:08:49 +0200
Subject: [PATCH] gpu_neon: tune frameskip further, allow >1

---
 frontend/menu.c        |  4 ++--
 plugins/gpu_neon/gpu.c | 42 ++++++++++++++++++++++++++++--------------
 plugins/gpu_neon/gpu.h |  3 ++-
 3 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/frontend/menu.c b/frontend/menu.c
index e720de6a..5fe86ade 100644
--- a/frontend/menu.c
+++ b/frontend/menu.c
@@ -255,7 +255,7 @@ static const struct {
 	CE_INTVAL(in_type_sel1),
 	CE_INTVAL(in_type_sel2),
 	CE_INTVAL(analog_deadzone),
-	CE_INTVAL_V(frameskip, 2),
+	CE_INTVAL_V(frameskip, 3),
 	CE_INTVAL_P(gpu_peops.iUseDither),
 	CE_INTVAL_P(gpu_peops.dwActFixes),
 	CE_INTVAL_P(gpu_unai.abe_hack),
@@ -1348,7 +1348,7 @@ static int mh_restore_defaults(int id, int keys)
 }
 
 static const char *men_region[]       = { "Auto", "NTSC", "PAL", NULL };
-static const char *men_frameskip[]    = { "Auto", "Off", "1", NULL };
+static const char *men_frameskip[]    = { "Auto", "Off", "1", "2", "3", NULL };
 /*
 static const char *men_confirm_save[] = { "OFF", "writes", "loads", "both", NULL };
 static const char h_confirm_save[]    = "Ask for confirmation when overwriting save,\n"
diff --git a/plugins/gpu_neon/gpu.c b/plugins/gpu_neon/gpu.c
index 990fc520..3f21fa99 100644
--- a/plugins/gpu_neon/gpu.c
+++ b/plugins/gpu_neon/gpu.c
@@ -59,14 +59,32 @@ static noinline void update_height(void)
 
 static noinline void decide_frameskip(void)
 {
-  gpu.frameskip.frame_ready = !gpu.frameskip.active;
+  if (gpu.frameskip.active)
+    gpu.frameskip.cnt++;
+  else {
+    gpu.frameskip.cnt = 0;
+    gpu.frameskip.frame_ready = 1;
+  }
 
-  if (!gpu.frameskip.active && (*gpu.frameskip.advice || gpu.frameskip.set == 1))
+  if (!gpu.frameskip.active && *gpu.frameskip.advice)
+    gpu.frameskip.active = 1;
+  else if (gpu.frameskip.set > 0 && gpu.frameskip.cnt < gpu.frameskip.set)
     gpu.frameskip.active = 1;
   else
     gpu.frameskip.active = 0;
 }
 
+static noinline void decide_frameskip_allow(uint32_t cmd_e3)
+{
+  // no frameskip if it decides to draw to display area,
+  // but not for interlace since it'll most likely always do that
+  uint32_t x = cmd_e3 & 0x3ff;
+  uint32_t y = (cmd_e3 >> 10) & 0x3ff;
+  gpu.frameskip.allow = gpu.status.interlace ||
+    (uint32_t)(x - gpu.screen.x) >= (uint32_t)gpu.screen.w ||
+    (uint32_t)(y - gpu.screen.y) >= (uint32_t)gpu.screen.h;
+}
+
 static noinline void get_gpu_info(uint32_t data)
 {
   switch (data & 0x0f) {
@@ -132,9 +150,12 @@ void GPUwriteStatus(uint32_t data)
     case 0x05:
       gpu.screen.x = data & 0x3ff;
       gpu.screen.y = (data >> 10) & 0x3ff;
-      if (gpu.frameskip.set && gpu.frameskip.last_flip_frame != *gpu.state.frame_count) {
-        decide_frameskip();
-        gpu.frameskip.last_flip_frame = *gpu.state.frame_count;
+      if (gpu.frameskip.set) {
+        decide_frameskip_allow(gpu.ex_regs[3]);
+        if (gpu.frameskip.last_flip_frame != *gpu.state.frame_count) {
+          decide_frameskip();
+          gpu.frameskip.last_flip_frame = *gpu.state.frame_count;
+        }
       }
       break;
     case 0x06:
@@ -294,15 +315,8 @@ static int check_cmd(uint32_t *data, int count)
         gpu.ex_regs[1] |= list[5] & 0x1ff;
       }
       else if (cmd == 0xe3)
-      {
-        // no frameskip if it decides to draw to display area,
-        // but not for interlace since it'll most likely always do that
-        uint32_t x = list[0] & 0x3ff;
-        uint32_t y = (list[0] >> 10) & 0x3ff;
-        gpu.frameskip.allow = gpu.status.interlace ||
-          (uint32_t)(x - gpu.screen.x) >= (uint32_t)gpu.screen.w ||
-          (uint32_t)(y - gpu.screen.y) >= (uint32_t)gpu.screen.h;
-      }
+        decide_frameskip_allow(list[0]);
+
       if (2 <= cmd && cmd < 0xc0)
         vram_dirty = 1;
       else if ((cmd & 0xf8) == 0xe0)
diff --git a/plugins/gpu_neon/gpu.h b/plugins/gpu_neon/gpu.h
index 8ad71c29..3b3e1de5 100644
--- a/plugins/gpu_neon/gpu.h
+++ b/plugins/gpu_neon/gpu.h
@@ -74,7 +74,8 @@ struct psx_gpu {
     } last_list;
   } state;
   struct {
-    int32_t set:3; /* -1 auto, 0 off, 1 fixed */
+    int32_t set:3; /* -1 auto, 0 off, 1-3 fixed */
+    int32_t cnt:3; /* amount skipped in a row */
     uint32_t active:1;
     uint32_t allow:1;
     uint32_t frame_ready:1;
-- 
2.39.5