nes6502i.h

   1 #ifndef __NES6502I_H
   2 #define __NES6502I_H
   3
   4 #include "types.h"
   5
   6 enum nes6502_instruction {
   7   INSN_AAC = 0, /* [Undocumented]Logical "And" byte with accumulator. If result is negative then carry is set. */
   8   INSN_AAX, /* [Undocumented]Logical "And" X register with accumulator and store result in memory. (No flags changed) */
   9   INSN_ADC, /* Add Memory to Accumulator with Carry */
  10   INSN_AND, /* Logical "And" Memory with Accumulator */
  11   INSN_ARR, /* [Undocumented]Logical "And" byte with accumulator, then rotate one bit right in accumulator and check bit 5 and 6. */
  12   INSN_ASL, /* Shift Left One Bit (Memory or Accumulator) */
  13   INSN_ASR, /* [Undocumented]Logical "And" byte with accumulator, then shift right one bit in accumulator. */
  14   INSN_ATX, /* [Undocumented]Logical "And" byte with accumulator, then transfer accumulator to X register. Or it could be (A = X = ((A | 0xEE) & data)).  Highly unpredictable.*/
  15   INSN_AXA, /* [Undocumented]Logical "And" X register with accumulator then AND result with (ADDR_HI + 1) and store in memory. Unpredictable. */
  16   INSN_AXS, /* [Undocumented]Logical "And" X register with accumulator and store result in X register, then subtract byte from X register (without borrow). (carry should work the same way as CMP) */
  17   INSN_BCC, /* Branch on Carry Clear */
  18   INSN_BCS, /* Branch on Carry Set */
  19   INSN_BEQ, /* Branch on Result Zero */
  20   INSN_BIT, /* Test Bits in Memory with Accumulator */
  21   INSN_BMI, /* Branch on Result Minus */
  22   INSN_BNE, /* Branch on Result not Zero */
  23   INSN_BPL, /* Branch on Result Plus */
  24   INSN_BRK, /* Force Break */
  25   INSN_BVC, /* Branch on Overflow Clear */
  26   INSN_BVS, /* Branch on Overflow Set */
  27   INSN_CLC, /* Clear Carry Flag */
  28   INSN_CLD, /* Clear Decimal Mode */
  29   INSN_CLI, /* Clear interrupt Disable Bit */
  30   INSN_CLV, /* Clear Overflow Flag */
  31   INSN_CMP, /* Compare Memory and Accumulator */
  32   INSN_CPX, /* Compare Memory and Index X */
  33   INSN_CPY, /* Compare Memory and Index Y */
  34   INSN_DCP, /* [Undocumented]Subtract 1 from memory (without borrow) and then compare with accumulator */
  35   INSN_DEC, /* Decrement Memory by One */
  36   INSN_DEX, /* Decrement Index X by One */
  37   INSN_DEY, /* Decrement Index Y by One */
  38   INSN_DOP, /* [Undocumented]Double NOP (fetches memory) */
  39   INSN_EOR, /* Logical "Exclusive-Or" Memory with Accumulator */
  40   INSN_HLT, /* [Undocumented] Halt (JAM) 6502. */
  41   INSN_INC, /* Increment Memory by One */
  42   INSN_INX, /* Increment Index X by One */
  43   INSN_INY, /* Increment Index Y by One */
  44   INSN_ISC, /* [Undocumented]Increase memory by one, then subtract memory from accumulator (with borrow) like SBC. */
  45   INSN_JMP, /* Jump to New Location */
  46   INSN_JSR, /* Jump to New Location Saving Return Address */
  47   INSN_LAR, /* [Undocumented]AND memory with stack pointer, transfer result to accumulator, X register and stack pointer. */
  48   INSN_LAX, /* [Undocumented]Load accumulator and X register with memory. */
  49   INSN_LDA, /* Load Accumulator with Memory */
  50   INSN_LDX, /* Load Index X with Memory */
  51   INSN_LDY, /* Load Index Y with Memory */
  52   INSN_LSR, /* Shift Right One Bit (Memory or Accumulator) */
  53   INSN_NOP, /* No Operation */
  54   INSN_ORA, /* Logical "Or" Memory with Accumulator */
  55   INSN_PHA, /* Push Accumulator on Stack */
  56   INSN_PHP, /* Push Processor Status on Stack */
  57   INSN_PLA, /* Pull Accumulator from Stack */
  58   INSN_PLP, /* Pull Processor Status from Stack */
  59   INSN_RLA, /* [Undocumented]Rotate one bit left in memory, then AND accumulator with memory. */
  60   INSN_ROL, /* Rotate One Bit Left (Memory or Accumulator) */
  61   INSN_ROR, /* Rotate One Bit Right (Memory or Accumulator) */
  62   INSN_RRA, /* [Undocumented]Rotate one bit right in memory, then add memory to accumulator (with carry). */
  63   INSN_RTI, /* Return from Interrupt */
  64   INSN_RTS, /* Return from Subroutine */
  65   INSN_SBC, /* Subtract Memory from Accumulator with Borrow */
  66   INSN_SEC, /* Set Carry Flag */
  67   INSN_SED, /* Set Decimal Mode */
  68   INSN_SEI, /* Set Interrupt Disable Status */
  69   INSN_SLO, /* [Undocumented]Shift left one bit in memory, then OR accumulator with memory. */
  70   INSN_SRE, /* [Undocumented]Shift right one bit in memory, then EOR accumulator with memory. */
  71   INSN_STA, /* Store Accumulator in Memory */
  72   INSN_STX, /* Store Index X in Memory */
  73   INSN_STY, /* Store Index Y in Memory */
  74   INSN_SXA, /* [Undocumented]AND X register with the high byte of the target address of the argument + 1. Store the result in memory. */
  75   INSN_SYA, /* [Undocumented]AND Y register with the high byte of the target address of the argument + 1. Store the result in memory. */
  76   INSN_TAX, /* Transfer Accumulator to Index X */
  77   INSN_TAY, /* Transfer Accumulator to Index Y */
  78   INSN_TOP, /* [Undocumented]Triple NOP */
  79   INSN_TSX, /* Transfer Stack Pointer to Index X */
  80   INSN_TXA, /* Transfer Index X to Accumulator */
  81   INSN_TXS, /* Transfer Index X to Stack Pointer */
  82   INSN_TYA, /* Transfer Index Y to Accumulator */
  83   INSN_XAA, /* [Undocumented]A = (A | #$EE) & X & #byte */
  84   INSN_XAS  /* [Undocumented]AND X register with accumulator and store result in stack pointer, then
  85                AND stack pointer with the high byte of the target address of the argument + 1. Store result in memory. */
  86 };
  87
  88 /* For the "details" field of nes6502_instruction_detail */
  89 #define I_RD  1 /* The instruction reads from memory */
  90 #define I_WR  2 /* The instruction writes to memory  */
  91 #define I_JP  4 /* It is a jump/branch (or related)  */
  92 #define I_ST  8 /* This instruction access the stack */
  93 #define I_UN 16 /* It is an undocumented instruction */
  94
  95
  96 /* For the used/changed registers in nes6502_instruction_detail */
  97 #define R_A  1
  98 #define R_X  2
  99 #define R_Y  4
 100 #define R_S  8
 101
 102 struct nes6502_instruction_detail {
 103   const char *name;
 104   uint32 details;
 105   uint32 changed_registers;
 106   uint32 used_registers;
 107   uint32 changed_flags;
 108   uint32 used_flags;
 109 };
 110
 111
 112 enum nes6502_addressing_mode {
 113   ADDR_ACCUMULATOR = 0,
 114   ADDR_IMMEDIATE,
 115   ADDR_ZERO_PAGE,
 116   ADDR_ZERO_PAGE_X,
 117   ADDR_ZERO_PAGE_Y,
 118   ADDR_ABSOLUTE,
 119   ADDR_ABSOLUTE_X,
 120   ADDR_ABSOLUTE_Y,
 121   ADDR_INDIRECT,
 122   ADDR_INDIRECT_X,
 123   ADDR_INDIRECT_Y,
 124   ADDR_RELATIVE,
 125   ADDR_IMPLIED
 126 };
 127
 128 struct nes6502_opcode {
 129   enum nes6502_addressing_mode addressing;
 130   enum nes6502_instruction instruction;
 131   uint32 cycles;
 132 };
 133
 134
 135 extern struct nes6502_instruction_detail nes6502_instructions[];
 136 extern struct nes6502_opcode nes6502_opcodes[];
 137 extern int nes6502_addressing_length[];
 138
 139 uint32 nes6502_disassemble (uint8 *mem, uint32 offset, int count);
 140
 141 #endif /* __NES6502I_H */