New timer based execution code

[virtualjaguar] / src / tom.cpp

diff --git a/src/tom.cpp b/src/tom.cpp
index 604f2cce1e5d96fa1cf85a20eab159edf2c97800..ca38c13c54fb879b52ac6d78b29f177d458c9d25 100644 (file)
--- a/src/tom.cpp
+++ b/src/tom.cpp
@@ -251,6 +251,9 @@
 #include "objectp.h"
 #include "cry2rgb.h"
 #include "settings.h"
+#include "clock.h"
+
+#define NEW_TIMER_SYSTEM
 
 // TOM registers (offset from $F00000)
 
@@ -969,7 +972,7 @@ uint16 topVisible = (vjs.hardwareTypeNTSC ? TOP_VISIBLE_VC : TOP_VISIBLE_VC_PAL)
                }
 
 //             TOMBackbuffer += GetSDLScreenPitch() / 2;       // Returns bytes, but we need words
-               TOMBackbuffer += GetSDLScreenPitch() / 4;       // Returns bytes, but we need dwords
+               TOMBackbuffer += GetSDLScreenWidthInPixels();
        }
 }
 
@@ -1467,8 +1470,16 @@ int tom_irq_enabled(int irq)
        return (tom_ram_8[0xE0] << 8) | tom_ram_8[0xE1];
 }*/
 
+// NEW:
+// TOM Programmable Interrupt Timer handler
+// NOTE: TOM's PIT is only enabled if the prescaler is != 0
+//       The PIT only generates an interrupt when it counts down to zero, not when loaded!
+
+void TOMPITCallback(void);
+
 void TOMResetPIT(void)
 {
+#ifndef NEW_TIMER_SYSTEM
 //Probably should *add* this amount to the counter to retain cycle accuracy! !!! FIX !!! [DONE]
 //Also, why +1??? 'Cause that's what it says in the JTRM...!
 //There is a small problem with this approach: If both the prescaler and the divider are equal
@@ -1476,6 +1487,16 @@ void TOMResetPIT(void)
        if (tom_timer_prescaler)
                tom_timer_counter += (1 + tom_timer_prescaler) * (1 + tom_timer_divider);
 //     WriteLog("tom: reseting timer to 0x%.8x (%i)\n",tom_timer_counter,tom_timer_counter);
+#else
+       // Need to remove previous timer from the queue, if it exists...
+       RemoveCallback(TOMPITCallback);
+       
+       if (tom_timer_prescaler)
+       {
+               double usecs = (float)(tom_timer_prescaler + 1) * (float)(tom_timer_divider + 1) * RISC_CYCLE_IN_USEC;
+               SetCallbackTime(TOMPITCallback, usecs);
+       }
+#endif
 }
 
 //
@@ -1499,3 +1520,17 @@ void TOMExecPIT(uint32 cycles)
                }
        }
 }
+
+
+void TOMPITCallback(void)
+{
+//     INT1_RREG |= 0x08;                         // Set TOM PIT interrupt pending
+       tom_set_pending_timer_int();
+    GPUSetIRQLine(GPUIRQ_TIMER, ASSERT_LINE);  // It does the 'IRQ enabled' checking
+
+//     if (INT1_WREG & 0x08)
+       if (tom_irq_enabled(IRQ_TIMER))
+               m68k_set_irq(7);                       // Generate 68K NMI
+
+       TOMResetPIT();
+}