1 files changed, 180 insertions, 0 deletions

diff --git a/apps/plugins/rockboy/lcdc.c b/apps/plugins/rockboy/lcdc.c
new file mode 100644
index 0000000000..c82b828354
--- /dev/null
+++ b/apps/plugins/rockboy/lcdc.c
@@ -0,0 +1,180 @@
+
+
+#include "rockmacros.h"
+
+#include "defs.h"
+#include "hw.h"
+#include "cpu.h"
+#include "regs.h"
+#include "lcd.h"
+
+
+#define C (cpu.lcdc)
+
+
+/*
+ * stat_trigger updates the STAT interrupt line to reflect whether any
+ * of the conditions set to be tested (by bits 3-6 of R_STAT) are met.
+ * This function should be called whenever any of the following occur:
+ * 1) LY or LYC changes.
+ * 2) A state transition affects the low 2 bits of R_STAT (see below).
+ * 3) The program writes to the upper bits of R_STAT.
+ * stat_trigger also updates bit 2 of R_STAT to reflect whether LY=LYC.
+ */
+
+void stat_trigger(void)
+{
+        static const int condbits[4] = { 0x08, 0x30, 0x20, 0x00 };
+        int flag = 0;
+
+        if ((R_LY < 0x91) && (R_LY == R_LYC))
+        {
+                R_STAT |= 0x04;
+                if (R_STAT & 0x40) flag = IF_STAT;
+        }
+        else R_STAT &= ~0x04;
+
+        if (R_STAT & condbits[R_STAT&3]) flag = IF_STAT;
+
+        if (!(R_LCDC & 0x80)) flag = 0;
+        
+        hw_interrupt(flag, IF_STAT);
+}
+
+void stat_write(byte b)
+{
+        R_STAT = (R_STAT & 0x07) | (b & 0x78);
+        if (!hw.cgb &&!(R_STAT & 2)) /* DMG STAT write bug => interrupt */
+                hw_interrupt(IF_STAT, IF_STAT);
+        stat_trigger();
+}
+
+
+/*
+ * stat_change is called when a transition results in a change to the
+ * LCD STAT condition (the low 2 bits of R_STAT).  It raises or lowers
+ * the VBLANK interrupt line appropriately and calls stat_trigger to
+ * update the STAT interrupt line.
+ */
+
+static void stat_change(int stat)
+{
+        stat &= 3;
+        R_STAT = (R_STAT & 0x7C) | stat;
+
+        if (stat != 1) hw_interrupt(0, IF_VBLANK);
+        /* hw_interrupt((stat == 1) ? IF_VBLANK : 0, IF_VBLANK); */
+        stat_trigger();
+}
+
+
+void lcdc_change(byte b)
+{
+        byte old = R_LCDC;
+        R_LCDC = b;
+        if ((R_LCDC ^ old) & 0x80) /* lcd on/off change */
+        {
+                R_LY = 0;
+                stat_change(2);
+                C = 40;
+                lcd_begin();
+        }
+}
+
+
+void lcdc_trans(void)
+{
+        if (!(R_LCDC & 0x80))
+        {
+                while (C <= 0)
+                {
+                        switch ((byte)(R_STAT & 3))
+                        {
+                        case 0:
+                        case 1:
+                                stat_change(2);
+                                C += 40;
+                                break;
+                        case 2:
+                                stat_change(3);
+                                C += 86;
+                                break;
+                        case 3:
+                                stat_change(0);
+                                if (hw.hdma & 0x80)
+                                        hw_hdma();
+                                else
+                                        C += 102;
+                                break;
+                        }
+                        return;
+                }
+        }
+        while (C <= 0)
+        {
+                switch ((byte)(R_STAT & 3))
+                {
+                case 1:
+                        if (!(hw.ilines & IF_VBLANK))
+                        {
+                                C += 218;
+                                hw_interrupt(IF_VBLANK, IF_VBLANK);
+                                break;
+                        }
+                        if (R_LY == 0)
+                        {
+                                lcd_begin();
+                                stat_change(2);
+                                C += 40;
+                                break;
+                        }
+                        else if (R_LY < 152)
+                                C += 228;
+                        else if (R_LY == 152)
+                                C += 28;
+                        else
+                        {
+                                R_LY = -1;
+                                C += 200;
+                        }
+                        R_LY++;
+                        stat_trigger();
+                        break;
+                case 2:
+                        lcd_refreshline();
+                        stat_change(3);
+                        C += 86;
+                        break;
+                case 3:
+                        stat_change(0);
+                        if (hw.hdma & 0x80)
+                                hw_hdma();
+                        /* FIXME -- how much of the hblank does hdma use?? */
+                        /* else */
+                        C += 102;
+                        break;
+                case 0:
+                        if (++R_LY >= 144)
+                        {
+                                if (cpu.halt)
+                                {
+                                        hw_interrupt(IF_VBLANK, IF_VBLANK);
+                                        C += 228;
+                                }
+                                else C += 10;
+                                stat_change(1);
+                                break;
+                        }
+                        stat_change(2);
+                        C += 40;
+                        break;
+                }
+        }
+}
+
+
+
+
+
+
+