8cb941985d
After a lot of preparatory work, we are now in position to finally tighten the types of the 6502 registers defined in the CPURegs struct of sim65. All registers were previously defined as bare 'unsigned', leading to subtle bugs where the bits beyond the 8 or 16 "true" bits in the register could become non-zero. Tightening the types of the registers to uint8_t and uint16_t as appropriate gets rid of these subtle bugs once and for all, assisted by the semantics of C when assigning an unsigned value to an unsigned type with less bits: the high-order bits are simply discarded, which is precisely what we'd want to happen. This change cleans up a lot of spurious failures of sim65 against the 65x02 test-set. For the 6502 and 65C02, we're now *functionally* compliant. For timing (i.e., clock cycle counts for each instruction), some work remains.
108 lines
4.3 KiB
C
108 lines
4.3 KiB
C
/*****************************************************************************/
|
|
/* */
|
|
/* 6502.h */
|
|
/* */
|
|
/* CPU core for the 6502 */
|
|
/* */
|
|
/* */
|
|
/* */
|
|
/* (C) 2003-2012, Ullrich von Bassewitz */
|
|
/* Roemerstrasse 52 */
|
|
/* D-70794 Filderstadt */
|
|
/* EMail: uz@cc65.org */
|
|
/* */
|
|
/* */
|
|
/* This software is provided 'as-is', without any expressed or implied */
|
|
/* warranty. In no event will the authors be held liable for any damages */
|
|
/* arising from the use of this software. */
|
|
/* */
|
|
/* Permission is granted to anyone to use this software for any purpose, */
|
|
/* including commercial applications, and to alter it and redistribute it */
|
|
/* freely, subject to the following restrictions: */
|
|
/* */
|
|
/* 1. The origin of this software must not be misrepresented; you must not */
|
|
/* claim that you wrote the original software. If you use this software */
|
|
/* in a product, an acknowledgment in the product documentation would be */
|
|
/* appreciated but is not required. */
|
|
/* 2. Altered source versions must be plainly marked as such, and must not */
|
|
/* be misrepresented as being the original software. */
|
|
/* 3. This notice may not be removed or altered from any source */
|
|
/* distribution. */
|
|
/* */
|
|
/*****************************************************************************/
|
|
|
|
|
|
|
|
#ifndef _6502_H
|
|
#define _6502_H
|
|
|
|
|
|
#include <stdint.h>
|
|
|
|
|
|
/*****************************************************************************/
|
|
/* Data */
|
|
/*****************************************************************************/
|
|
|
|
|
|
|
|
/* Supported CPUs */
|
|
typedef enum CPUType {
|
|
CPU_6502,
|
|
CPU_65C02,
|
|
CPU_6502X
|
|
} CPUType;
|
|
|
|
/* Current CPU */
|
|
extern CPUType CPU;
|
|
|
|
/* 6502 CPU registers */
|
|
typedef struct CPURegs CPURegs;
|
|
struct CPURegs {
|
|
uint8_t AC; /* Accumulator */
|
|
uint8_t XR; /* X register */
|
|
uint8_t YR; /* Y register */
|
|
uint8_t SR; /* Status register */
|
|
uint8_t SP; /* Stackpointer */
|
|
uint16_t PC; /* Program counter */
|
|
};
|
|
|
|
/* Current CPU registers */
|
|
extern CPURegs Regs;
|
|
|
|
/* Status register bits */
|
|
#define CF 0x01 /* Carry flag */
|
|
#define ZF 0x02 /* Zero flag */
|
|
#define IF 0x04 /* Interrupt flag */
|
|
#define DF 0x08 /* Decimal flag */
|
|
#define BF 0x10 /* Break flag */
|
|
#define OF 0x40 /* Overflow flag */
|
|
#define SF 0x80 /* Sign flag */
|
|
|
|
|
|
|
|
/*****************************************************************************/
|
|
/* Code */
|
|
/*****************************************************************************/
|
|
|
|
|
|
|
|
void Reset (void);
|
|
/* Generate a CPU RESET */
|
|
|
|
void IRQRequest (void);
|
|
/* Generate an IRQ */
|
|
|
|
void NMIRequest (void);
|
|
/* Generate an NMI */
|
|
|
|
unsigned ExecuteInsn (void);
|
|
/* Execute one CPU instruction. Return the number of clock cycles for the
|
|
** executed instruction.
|
|
*/
|
|
|
|
|
|
/* End of 6502.h */
|
|
|
|
#endif
|