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127 lines
2.9 KiB
C++
127 lines
2.9 KiB
C++
/********************************************************************************/
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/* */
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/* CZ80 exec include source file */
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/* C Z80 emulator version 0.92 */
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/* Copyright 2004-2005 Stéphane Dallongeville */
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/* */
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/********************************************************************************/
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s32 Z80_ICount;
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s32 CZ80_FASTCALL Cz80_Exec(cz80_struc *cpu, s32 cycles)
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{
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#if CZ80_USE_JUMPTABLE
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#include "cz80jmp.inc"
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#endif
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#if __x86__
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register cz80_struc *CPU asm ("ebx");
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register u8 *PC asm ("esi");
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register u32 Opcode asm ("edx");
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#else
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cz80_struc *CPU;
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u8 *PC;
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u32 Opcode;
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#endif
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CPU = cpu;
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PC = CPU->PC;
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if (CPU->Status & (CZ80_RUNNING | CZ80_DISABLE | CZ80_FAULTED))
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{
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return (CPU->Status | 0x80000000);
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}
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CPU->CycleToDo = Z80_ICount = cycles;
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CPU->CycleSup = 0;
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CPU->Status |= CZ80_RUNNING;
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Cz80_Check_Int:
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// check for interrupt
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if (CPU->Status & (zIFF1 | CZ80_HAS_NMI))
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{
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u32 newPC;
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if (CPU->Status & CZ80_HAS_NMI)
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{
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// NMI
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CPU->Status &= ~(CZ80_HALTED | CZ80_HAS_NMI);
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zIFF1 = 0;
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newPC = 0x66;
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}
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else
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{
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// INT
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CPU->Status &= ~(CZ80_HALTED | CZ80_HAS_INT);
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zIFF= 0;
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// IM = 1
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if (zIM == 1) newPC = 0x38;
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else
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{
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u32 adr;
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Opcode = CPU->IntVect & 0xFF;
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// IM = 0
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if (zIM == 0)
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goto Cz80_Exec_direct;
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// IM = 2
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adr = Opcode | (zI << 8);
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READ_WORD(adr, newPC)
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#if CZ80_IRQ_CYCLES
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Z80_ICount -= 8;
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#endif
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}
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}
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// set new PC
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{
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u32 src = zRealPC;
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PUSH_16(src)
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SET_PC(newPC);
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#if CZ80_IRQ_CYCLES
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Z80_ICount -= 11;
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#endif
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}
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}
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// if some cycles left
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if ((Z80_ICount += CPU->CycleSup) > 0)
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{
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CPU->CycleSup = 0;
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if (!(CPU->Status & CZ80_HALTED)) goto Cz80_Exec;
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// CPU halted
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Z80_ICount = 0;
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}
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Cz80_Exec_Really_End:
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// no more cycles, end execution
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CPU->Status &= ~CZ80_RUNNING;
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CPU->PC = PC;
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// number of executed cycles
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Z80_ICount = CPU->CycleToDo - Z80_ICount;
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// update R register
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zR = (zR + (Z80_ICount >> 2)) & 0x7F;
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return Z80_ICount;
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#if CZ80_SIZE_OPT
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Cz80_Exec_Check:
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if (Z80_ICount <= 0) goto Cz80_Check_Int;
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#endif
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Cz80_Exec:
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{
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Opcode = REAL_FETCH_BYTE;
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Cz80_Exec_direct:
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{
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union16 *data = pzHL;
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#include "cz80_op.inc"
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}
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}
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}
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