exit HALT when IF!=0, even if interrupts disabled

diff --git a/core/GameBoy.cc b/core/GameBoy.cc
index 796f166ca42fc0abf642106209889b02566db471..d0efca9e3a4967e0751864b04683e7ec67c9fc0b 100644 (file)
--- a/core/GameBoy.cc
+++ b/core/GameBoy.cc
@@ -182,9 +182,14 @@ GameBoy::run_status GameBoy::run_cycle()
                // Check for interrupts before opcode fetching
                u8 IE=memory.high[GBMemory::I_IE];
                //logger.trace("IME=", int(IME), " IE=", int(IE));
+
+               // bugfix (blargg test 02-halt): cpu exits from halt state if there is an interrupt flag raised,
+               // even if interrupts are globally disabled
+                u8 IF = memory.high[GBMemory::I_IF];
+                if (HALT && IF) HALT=false;
+
                if (IME && IE)
                {
-                       u8 IF = memory.high[GBMemory::I_IF];
                        //logger.trace("Dispatching interrupts: IE=", int(IE), " IF=", int(IF));
                        if (IF)
                        {
@@ -194,7 +199,6 @@ GameBoy::run_status GameBoy::run_cycle()
                                        IF &= (~IRQ_VBLANK);
                                        do_call(0x40);
                                        logger.trace("VBLANK IRQ");
-                                       HALT=false;
                                }
                                else if ((IF & IRQ_LCD_STAT) && (IE & IRQ_LCD_STAT))
                                {
@@ -202,7 +206,6 @@ GameBoy::run_status GameBoy::run_cycle()
                                        IF &= (~IRQ_LCD_STAT);
                                        do_call(0x48);
                                        logger.trace("LCD STAT IRQ");
-                                       HALT=false;
                                } 
                                else if ((IF & IRQ_TIMER) && (IE & IRQ_TIMER))
                                {
@@ -210,7 +213,6 @@ GameBoy::run_status GameBoy::run_cycle()
                                        IF &= (~IRQ_TIMER);
                                        do_call(0x50);
                                        logger.trace("TIMER IRQ");
-                                       HALT=false;
                                }
                                else if ((IF & IRQ_SERIAL) && (IE & IRQ_SERIAL))   
                                {
@@ -218,7 +220,6 @@ GameBoy::run_status GameBoy::run_cycle()
                                        IF &= (~IRQ_SERIAL);
                                        do_call(0x58);
                                        logger.trace("SERIAL IRQ");
-                                       HALT=false;
                                }
                                else if ((IF & IRQ_JOYPAD) && (IE & IRQ_JOYPAD))     
                                {
@@ -226,7 +227,6 @@ GameBoy::run_status GameBoy::run_cycle()
                                        IF &= (~IRQ_JOYPAD);
                                        do_call(0x60);
                                        logger.trace("JOYPAD IRQ");
-                                       HALT=false;
                                }
                        }
                        memory.high[GBMemory::I_IF] = IF;