0081fe548c
MaxCycleCount is accounted by countdown, eliminating the 1-instruction-overhead issue, and removing the need to compare against a growing TotalCycles. Makes main.c responsible for counting total cycles, instead of 6502.c, so the size of MaxCycleCount etc. is fully determined in one location. Makes error.c responsible for PrintCycles instead of paravirt.c, so that it can be treated globally instead of Return value of main() should be SIM65_ERROR because it is unreachable by design.
103 lines
4.2 KiB
C
103 lines
4.2 KiB
C
/*****************************************************************************/
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/* */
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/* 6502.h */
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/* */
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/* CPU core for the 6502 */
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/* */
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/* */
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/* */
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/* (C) 2003-2012, Ullrich von Bassewitz */
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/* Roemerstrasse 52 */
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/* D-70794 Filderstadt */
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/* EMail: uz@cc65.org */
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/* */
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/* */
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/* This software is provided 'as-is', without any expressed or implied */
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/* warranty. In no event will the authors be held liable for any damages */
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/* arising from the use of this software. */
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/* */
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/* Permission is granted to anyone to use this software for any purpose, */
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/* including commercial applications, and to alter it and redistribute it */
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/* freely, subject to the following restrictions: */
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/* */
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/* 1. The origin of this software must not be misrepresented; you must not */
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/* claim that you wrote the original software. If you use this software */
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/* in a product, an acknowledgment in the product documentation would be */
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/* appreciated but is not required. */
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/* 2. Altered source versions must be plainly marked as such, and must not */
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/* be misrepresented as being the original software. */
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/* 3. This notice may not be removed or altered from any source */
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/* distribution. */
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/* */
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/*****************************************************************************/
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#ifndef _6502_H
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#define _6502_H
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/*****************************************************************************/
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/* Data */
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/*****************************************************************************/
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/* Supported CPUs */
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typedef enum CPUType {
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CPU_6502,
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CPU_65C02
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} CPUType;
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/* Current CPU */
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extern CPUType CPU;
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/* 6502 CPU registers */
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typedef struct CPURegs CPURegs;
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struct CPURegs {
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unsigned AC; /* Accumulator */
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unsigned XR; /* X register */
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unsigned YR; /* Y register */
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unsigned ZR; /* Z register */
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unsigned SR; /* Status register */
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unsigned SP; /* Stackpointer */
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unsigned PC; /* Program counter */
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};
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/* Status register bits */
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#define CF 0x01 /* Carry flag */
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#define ZF 0x02 /* Zero flag */
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#define IF 0x04 /* Interrupt flag */
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#define DF 0x08 /* Decimal flag */
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#define BF 0x10 /* Break flag */
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#define OF 0x40 /* Overflow flag */
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#define SF 0x80 /* Sign flag */
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/*****************************************************************************/
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/* Code */
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/*****************************************************************************/
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void Reset (void);
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/* Generate a CPU RESET */
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void IRQRequest (void);
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/* Generate an IRQ */
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void NMIRequest (void);
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/* Generate an NMI */
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unsigned ExecuteInsn (void);
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/* Execute one CPU instruction. Return the number of clock cycles for the
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** executed instruction.
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*/
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/* End of 6502.h */
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#endif
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