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https://github.com/joncampbell123/dosbox-x.git
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4eb7d99867
hack" has been added to deal with a handful of DOS games/demos with flawed Sound Blaster interrupt service routines. Currently, the only hack available is to specify that the Sound Blaster IRQ should fire only when CPU segment registers CS and DS match. The reason for this hack is 1993 demo "Saga" by Dust. The demo's Sound Blaster IRQ handler uses DS to refer to local storage in the code segment but it does not load DS to make the access valid. Sooner or later, the ISR is triggered when DS != CS (usually when the demo is busy drawing on the screen), and the Sound Blaster IRQ handler hangs. Enabling this hack ensure the buggy ISR does not hang.
78 lines
2.5 KiB
C
78 lines
2.5 KiB
C
/*
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* Copyright (C) 2002-2013 The DOSBox Team
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifndef DOSBOX_PIC_H
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#define DOSBOX_PIC_H
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/* CPU Cycle Timing */
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extern Bit32s CPU_Cycles;
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extern Bit32s CPU_CycleLeft;
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extern Bit32s CPU_CycleMax;
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typedef void (PIC_EOIHandler) (void);
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typedef void (* PIC_EventHandler)(Bitu val);
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enum PIC_irq_hacks {
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PIC_irq_hack_none=0, // dispatch IRQ normally
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PIC_irq_hack_cs_equ_ds // do not fire IRQ unless segment registers in the CPU are DS == CS
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// explanation: a handful of games and demos have Sound Blaster interrupt service
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// routines that assume DS == CS and they make no attempt to reload DS to refer
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// to local variables properly. eventually these programs crash or malfunction
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// because sooner or later, the ISR is called with CS != DS. This hack can be
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// used to prevent those games/demos from crashing.
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};
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extern enum PIC_irq_hacks PIC_IRQ_hax[16];
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void PIC_Set_IRQ_hack(int IRQ,enum PIC_irq_hacks hack);
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enum PIC_irq_hacks PIC_parse_IRQ_hack_string(const char *str);
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extern Bitu PIC_IRQCheck;
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extern Bitu PIC_Ticks;
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static INLINE float PIC_TickIndex(void) {
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return (CPU_CycleMax-CPU_CycleLeft-CPU_Cycles)/(float)CPU_CycleMax;
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}
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static INLINE Bits PIC_TickIndexND(void) {
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return CPU_CycleMax-CPU_CycleLeft-CPU_Cycles;
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}
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static INLINE Bits PIC_MakeCycles(double amount) {
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return (Bits)(CPU_CycleMax*amount);
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}
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static INLINE double PIC_FullIndex(void) {
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return PIC_Ticks+(double)PIC_TickIndex();
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}
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void PIC_ActivateIRQ(Bitu irq);
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void PIC_DeActivateIRQ(Bitu irq);
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void PIC_runIRQs(void);
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bool PIC_RunQueue(void);
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//Delay in milliseconds
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void PIC_AddEvent(PIC_EventHandler handler,float delay,Bitu val=0);
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void PIC_RemoveEvents(PIC_EventHandler handler);
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void PIC_RemoveSpecificEvents(PIC_EventHandler handler, Bitu val);
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void PIC_SetIRQMask(Bitu irq, bool masked);
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#endif
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