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Annotation of previous/src/cycles.c, revision 1.1

1.1     ! root        1: /*
        !             2:   Hatari - cycles.c
        !             3: 
        !             4:   This file is distributed under the GNU Public License, version 2 or at
        !             5:   your option any later version. Read the file gpl.txt for details.
        !             6: 
        !             7:   Here we take care of cycle counters. For performance reasons we don't increase
        !             8:   all counters after each 68k instruction, but only one main counter.
        !             9:   When we need to read one of the normal counters (currently only for video
        !            10:   and sound cycles), we simply update these counters with the main counter
        !            11:   before returning the current counter value.
        !            12: */
        !            13: 
        !            14: 
        !            15: /* 2007/03/xx  [NP]    Use 'CurrentInstrCycles' to get a good approximation for        */
        !            16: /*                     Cycles_GetCounterOnReadAccess and Cycles_GetCounterOnWriteAccess*/
        !            17: /*                     (this should work correctly with 'move' instruction).           */
        !            18: /* 2008/04/14  [NP]    Take nWaitStateCycles into account when computing the value of  */
        !            19: /*                     Cycles_GetCounterOnReadAccess and Cycles_GetCounterOnWriteAccess*/
        !            20: /* 2008/12/21  [NP]    Use BusMode to adjust Cycles_GetCounterOnReadAccess and         */
        !            21: /*                     Cycles_GetCounterOnWriteAccess depending on who is owning the   */
        !            22: /*                     bus (cpu, blitter).                                             */
        !            23: 
        !            24: 
        !            25: const char Cycles_fileid[] = "Hatari cycles.c : " __DATE__ " " __TIME__;
        !            26: 
        !            27: #include "main.h"
        !            28: #include "m68000.h"
        !            29: #include "memorySnapShot.h"
        !            30: #include "cycles.h"
        !            31: 
        !            32: 
        !            33: int nCyclesMainCounter;                                /* Main cycles counter */
        !            34: 
        !            35: static int nCyclesCounter[CYCLES_COUNTER_MAX]; /* Array with all counters */
        !            36: 
        !            37: int CurrentInstrCycles;
        !            38: 
        !            39: 
        !            40: 
        !            41: /*-----------------------------------------------------------------------*/
        !            42: /**
        !            43:  * Save/Restore snapshot of local variables ('MemorySnapShot_Store' handles type)
        !            44:  */
        !            45: void Cycles_MemorySnapShot_Capture(bool bSave)
        !            46: {
        !            47:        /* Save/Restore details */
        !            48:        MemorySnapShot_Store(&nCyclesMainCounter, sizeof(nCyclesMainCounter));
        !            49:        MemorySnapShot_Store(nCyclesCounter, sizeof(nCyclesCounter));
        !            50:        MemorySnapShot_Store(&CurrentInstrCycles, sizeof(CurrentInstrCycles));
        !            51: }
        !            52: 
        !            53: 
        !            54: /*-----------------------------------------------------------------------*/
        !            55: /**
        !            56:  * Update all cycles counters with the current value of nCyclesMainCounter.
        !            57:  */
        !            58: static void Cycles_UpdateCounters(void)
        !            59: {
        !            60:        int i;
        !            61: 
        !            62:        for (i = 0; i < CYCLES_COUNTER_MAX; i++)
        !            63:        {
        !            64:                nCyclesCounter[i] += nCyclesMainCounter;
        !            65:        }
        !            66: 
        !            67:        nCyclesMainCounter = 0;
        !            68: }
        !            69: 
        !            70: 
        !            71: /*-----------------------------------------------------------------------*/
        !            72: /**
        !            73:  * Set a counter to a new value.
        !            74:  */
        !            75: void Cycles_SetCounter(int nId, int nValue)
        !            76: {
        !            77:        /* Update counters first (nCyclesMainCounter must be 0 afterwards) */
        !            78:        Cycles_UpdateCounters();
        !            79: 
        !            80:        /* Now set the new value: */
        !            81:        nCyclesCounter[nId] = nValue;
        !            82: }
        !            83: 
        !            84: 
        !            85: /*-----------------------------------------------------------------------*/
        !            86: /**
        !            87:  * Read a counter.
        !            88:  */
        !            89: int Cycles_GetCounter(int nId)
        !            90: {
        !            91:        /* Update counters first so we read an up-to-date value */
        !            92:        Cycles_UpdateCounters();
        !            93: 
        !            94:        return nCyclesCounter[nId];
        !            95: }
        !            96: 
        !            97: 
        !            98: /*-----------------------------------------------------------------------*/
        !            99: /**
        !           100:  * Read a counter on CPU memory read access by taking care of the instruction
        !           101:  * type (add the needed amount of additional cycles).
        !           102:  */
        !           103: int Cycles_GetCounterOnReadAccess(int nId)
        !           104: {
        !           105:        int nAddCycles;
        !           106: 
        !           107:        /* Update counters first so we read an up-to-date value */
        !           108:        Cycles_UpdateCounters();
        !           109: 
        !           110:        if ( BusMode == BUS_MODE_BLITTER )
        !           111:        {
        !           112:                nAddCycles = 4 + nWaitStateCycles;
        !           113:        }
        !           114:        else                                                    /* BUS_MODE_CPU */
        !           115:        {
        !           116:                /* TODO: Find proper cycles count depending on the type of the current instruction */
        !           117:                /* (e.g. movem is not correctly handled) */
        !           118:                nAddCycles = CurrentInstrCycles + nWaitStateCycles;     /* read is effective at the end of the instr ? */
        !           119:        }
        !           120: 
        !           121:        return nCyclesCounter[nId] + nAddCycles;
        !           122: }
        !           123: 
        !           124: 
        !           125: /*-----------------------------------------------------------------------*/
        !           126: /**
        !           127:  * Read a counter on CPU memory write access by taking care of the instruction
        !           128:  * type (add the needed amount of additional cycles).
        !           129:  */
        !           130: int Cycles_GetCounterOnWriteAccess(int nId)
        !           131: {
        !           132:        int nAddCycles;
        !           133: 
        !           134:        /* Update counters first so we read an up-to-date value */
        !           135:        Cycles_UpdateCounters();
        !           136: 
        !           137:        if ( BusMode == BUS_MODE_BLITTER )
        !           138:        {
        !           139:                nAddCycles = 4 + nWaitStateCycles;
        !           140:        }
        !           141:        else                                                    /* BUS_MODE_CPU */
        !           142:        {
        !           143:                /* TODO: Find proper cycles count depending on the type of the current instruction */
        !           144:                /* (e.g. movem is not correctly handled) */
        !           145:                nAddCycles = CurrentInstrCycles + nWaitStateCycles;
        !           146: 
        !           147:                /* assume the behaviour of a 'move' (since this is the most */
        !           148:                /* common instr used when requiring cycle precise writes) */
        !           149:                if ( nAddCycles >= 8 )
        !           150:                        nAddCycles -= 4;                        /* last 4 cycles are for prefetch */
        !           151:        }
        !           152: 
        !           153:        return nCyclesCounter[nId] + nAddCycles;
        !           154: }

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