Fixed problem with frames running ahead of the sound thread.

[apple2] / src / v65c02.cpp

diff --git a/src/v65c02.cpp b/src/v65c02.cpp
index 216a0aff313c78a4723fb97db113d2c8235b795d..7f86895c6927f5ff3afff81299bcebe13fc566df 100755 (executable)
--- a/src/v65c02.cpp
+++ b/src/v65c02.cpp
@@ -2850,6 +2850,9 @@ bool dumpDis = false;
 //bleh.
 //static uint32_t limit = 0;
 
+// This should be in the regs struct, in case we have multiple CPUs...
+#warning "!!! Move overflow into regs struct !!!"
+static uint64_t overflow = 0;
 //
 // Function to execute 65C02 for "cycles" cycles
 //
@@ -2875,7 +2878,7 @@ Let's see...
        if (regs.clock + cycles > 0xFFFFFFFF)
                wraparound = true;
 */
-       uint64_t endCycles = regs.clock + (uint64_t)cycles;
+       uint64_t endCycles = regs.clock + (uint64_t)cycles - overflow;
 
        while (regs.clock < endCycles)
        {
@@ -3020,6 +3023,12 @@ WriteLog("\n*** IRQ ***\n\n");
                }
        }
 
+       // If we went longer than the passed in cycles, make a note of it so we can
+       // subtract it out from a subsequent run. It's guaranteed to be positive,
+       // because the condition that exits the main loop above is written such
+       // that regs.clock has to be larger than endCycles to exit from it.
+       overflow = regs.clock - endCycles;
+
        myMemcpy(context, &regs, sizeof(V65C02REGS));
 }