git.sur5r.net Git - cc65/blob - src/sim65/6502.h

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                  6502.h                                   */
   4 /*                                                                           */
   5 /*                           CPU core for the 6502                           */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2003-2012, Ullrich von Bassewitz                                      */
  10 /*                Roemerstrasse 52                                           */
  11 /*                D-70794 Filderstadt                                        */
  12 /* EMail:         uz@cc65.org                                                */
  13 /*                                                                           */
  14 /*                                                                           */
  15 /* This software is provided 'as-is', without any expressed or implied       */
  16 /* warranty.  In no event will the authors be held liable for any damages    */
  17 /* arising from the use of this software.                                    */
  18 /*                                                                           */
  19 /* Permission is granted to anyone to use this software for any purpose,     */
  20 /* including commercial applications, and to alter it and redistribute it    */
  21 /* freely, subject to the following restrictions:                            */
  22 /*                                                                           */
  23 /* 1. The origin of this software must not be misrepresented; you must not   */
  24 /*    claim that you wrote the original software. If you use this software   */
  25 /*    in a product, an acknowledgment in the product documentation would be  */
  26 /*    appreciated but is not required.                                       */
  27 /* 2. Altered source versions must be plainly marked as such, and must not   */
  28 /*    be misrepresented as being the original software.                      */
  29 /* 3. This notice may not be removed or altered from any source              */
  30 /*    distribution.                                                          */
  31 /*                                                                           */
  32 /*****************************************************************************/
  33
  34
  35
  36 #ifndef _6502_H
  37 #define _6502_H
  38
  39
  40
  41 /*****************************************************************************/
  42 /*                                   Data                                    */
  43 /*****************************************************************************/
  44
  45
  46
  47 /* Supported CPUs */
  48 typedef enum CPUType {
  49     CPU_6502,
  50     CPU_65C02
  51 } CPUType;
  52
  53 /* Current CPU */
  54 extern CPUType CPU;
  55
  56 /* 6502 CPU registers */
  57 typedef struct CPURegs CPURegs;
  58 struct CPURegs {
  59     unsigned    AC;             /* Accumulator */
  60     unsigned    XR;             /* X register */
  61     unsigned    YR;             /* Y register */
  62     unsigned    ZR;             /* Z register */
  63     unsigned    SR;             /* Status register */
  64     unsigned    SP;             /* Stackpointer */
  65     unsigned    PC;             /* Program counter */
  66 };
  67
  68 /* Status register bits */
  69 #define CF      0x01            /* Carry flag */
  70 #define ZF      0x02            /* Zero flag */
  71 #define IF      0x04            /* Interrupt flag */
  72 #define DF      0x08            /* Decimal flag */
  73 #define BF      0x10            /* Break flag */
  74 #define OF      0x40            /* Overflow flag */
  75 #define SF      0x80            /* Sign flag */
  76
  77
  78
  79 /*****************************************************************************/
  80 /*                                   Code                                    */
  81 /*****************************************************************************/
  82
  83
  84
  85 void Reset (void);
  86 /* Generate a CPU RESET */
  87
  88 void IRQRequest (void);
  89 /* Generate an IRQ */
  90
  91 void NMIRequest (void);
  92 /* Generate an NMI */
  93
  94 unsigned ExecuteInsn (void);
  95 /* Execute one CPU instruction. Return the number of clock cycles for the
  96 ** executed instruction.
  97 */
  98
  99 unsigned long GetCycles (void);
 100 /* Return the total number of clock cycles executed */
 101
 102 extern int PrintCycles;
 103 /* flag to print cycles at program termination */
 104
 105
 106 /* End of 6502.h */
 107
 108 #endif