mpu6502.py

from py65.utils.conversions import convert_to_bin, convert_to_bcd, itoa
from py65.utils.devices import make_instruction_decorator

class MPU:
    # vectors
    ResetTo = 0xfffc
    IrqTo   = 0xfffe
    NMITo   = 0xfffa

    # processor flags
    NEGATIVE  = 128
    OVERFLOW  = 64
    UNUSED    = 32
    BREAK     = 16 # there is no BREAK flag, but this position indicates BREAK
    DECIMAL   = 8
    INTERRUPT = 4
    ZERO      = 2
    CARRY     = 1

    BYTE_WIDTH  = 8
    BYTE_FORMAT = "%02x"
    ADDR_WIDTH  = 16
    ADDR_FORMAT = "%04x"

    def __init__(self, memory=None, pc=0x0000):
        # config
        self.name = '6502'
        self.byteMask = ((1<<self.BYTE_WIDTH)-1)
        self.addrMask = ((1<<self.ADDR_WIDTH)-1)
        self.addrHighMask = (self.byteMask<<self.BYTE_WIDTH)
        self.spBase = 1<<self.BYTE_WIDTH

        # vm status
        self.excycles = 0
        self.addcycles = False
        self.processorCycles = 0

        if memory is None:
            memory = 0x10000 * [0x00]
        self.memory = memory
        self.start_pc = pc

        # init
        self.reset()

    def reprformat(self):
        return ("%s PC  AC XR YR SP NV-BDIZC\n" + \
                "%s: %04x %02x %02x %02x %02x %s"
               )

    def __repr__(self):
        flags  = itoa(self.p, 2).rjust(self.BYTE_WIDTH, '0')
        indent = ' ' * (len(self.name) + 2)

        return self.reprformat() % (indent, self.name,
                      self.pc, self.a, self.x, self.y, self.sp, flags)

    def step(self):
        instructCode = self.memory[self.pc]
        self.pc = (self.pc + 1) & self.addrMask
        self.excycles = 0
        self.addcycles = self.extracycles[instructCode]
        self.instruct[instructCode](self)
        self.processorCycles += self.cycletime[instructCode]+self.excycles
        return self

    def reset(self):
        self.pc = self.start_pc
        self.sp = self.byteMask
        self.a = 0
        self.x = 0
        self.y = 0
        self.p = self.p = self.BREAK | self.UNUSED
        self.processorCycles = 0

    # Helpers for addressing modes

    def ByteAt(self, addr):
        return self.memory[addr]

    def WordAt(self, addr):
        return self.ByteAt(addr) + (self.ByteAt(addr + 1) << self.BYTE_WIDTH)

    def WrapAt(self, addr):
        wrap = lambda x: (x & self.addrHighMask) + ((x + 1) & self.byteMask)
        return self.ByteAt(addr) + (self.ByteAt(wrap(addr)) << self.BYTE_WIDTH)

    def ProgramCounter(self):
        return self.pc

    # Addressing modes

    def ImmediateByte(self):
        return self.ByteAt(self.pc)

    def ZeroPageAddr(self):
        return self.ByteAt(self.pc)

    def ZeroPageXAddr(self):
        return self.byteMask & (self.x + self.ByteAt(self.pc))

    def ZeroPageYAddr(self):
        return self.byteMask & (self.y + self.ByteAt(self.pc))

    def IndirectXAddr(self):
        return self.WrapAt( self.byteMask & (self.ByteAt(self.pc) + self.x))

    def IndirectYAddr(self):
        if self.addcycles:
            a1 = self.WrapAt(self.ByteAt(self.pc))
            a2 = (a1+self.y) & self.addrMask
            if (a1 & self.addrHighMask) != (a2 & self.addrHighMask):
                self.excycles += 1
            return a2
        else:
            return (self.WrapAt(self.ByteAt(self.pc))+self.y)&self.addrMask

    def AbsoluteAddr(self):
      return self.WordAt(self.pc)

    def AbsoluteXAddr(self):
        if self.addcycles:
            a1 = self.WordAt(self.pc)
            a2 = (a1 + self.x) & self.addrMask
            if (a1 & self.addrHighMask) != (a2 & self.addrHighMask):
                self.excycles += 1
            return a2
        else:
            return (self.WordAt(self.pc)+self.x)&self.addrMask

    def AbsoluteYAddr(self):
        if self.addcycles:
            a1 = self.WordAt(self.pc)
            a2 = (a1 + self.y) & self.addrMask
            if (a1 & self.addrHighMask) != (a2 & self.addrHighMask):
                self.excycles += 1
            return a2
        else:
            return (self.WordAt(self.pc)+self.y)&self.addrMask

    def BranchRelAddr(self):
        self.excycles += 1
        addr = self.ImmediateByte()
        self.pc += 1

        if addr & self.NEGATIVE:
            addr = self.pc - (addr ^ self.byteMask) - 1
        else:
            addr = self.pc + addr

        if (self.pc & self.addrHighMask) != (addr & self.addrHighMask):
            self.excycles += 1

        self.pc = addr & self.addrMask

    # stack

    def stPush(self,z):
        self.memory[self.sp+self.spBase] = z&self.byteMask
        self.sp -= 1
        self.sp &= self.byteMask

    def stPop(self):
        self.sp += 1
        self.sp &= self.byteMask
        return self.ByteAt(self.sp+self.spBase)

    def stPushWord(self, z):
        self.stPush((z>>self.BYTE_WIDTH)&self.byteMask)
        self.stPush(z&self.byteMask)

    def stPopWord(self):
        z = self.stPop()
        z += self.stPop()<<self.BYTE_WIDTH
        return z

    def FlagsNZ(self, value):
        self.p &= ~(self.ZERO + self.NEGATIVE)
        if value == 0:
            self.p |= self.ZERO
        else:
            self.p |= value & self.NEGATIVE

    # operations

    def opORA(self, x):
        self.a |= self.ByteAt(x())
        self.FlagsNZ(self.a)

    def opASL(self, x):
        if x is None:
            tbyte = self.a
        else:
            addr = x()
            tbyte = self.ByteAt(addr)

        self.p &= ~(self.CARRY + self.NEGATIVE + self.ZERO)

        if tbyte & self.NEGATIVE:
            self.p |= self.CARRY
        tbyte = (tbyte << 1) & self.byteMask

        if tbyte:
            self.p |= tbyte & self.NEGATIVE
        else:
            self.p |= self.ZERO

        if x is None:
            self.a = tbyte
        else:
            self.memory[addr] = tbyte

    def opLSR(self, x):
        if x is None:
            tbyte = self.a
        else:
            addr = x()
            tbyte = self.ByteAt(addr)

        self.p &=~(self.CARRY+self.NEGATIVE+self.ZERO)
        self.p |=tbyte&1

        tbyte = tbyte >> 1
        if tbyte:
            pass # {}
        else:
            self.p |= self.ZERO

        if x is None:
            self.a = tbyte
        else:
            self.memory[addr]=tbyte

    def opBCL(self, x):
      if self.p & x:
        self.pc += 1
      else:
          self.BranchRelAddr()

    def opBST(self, x):
      if self.p & x:
          self.BranchRelAddr()
      else:
          self.pc += 1

    def opCLR(self, x):
        self.p &=~x

    def opSET(self, x):
        self.p |= x

    def opAND(self, x):
        self.a &= self.ByteAt(x())
        self.FlagsNZ(self.a)

    def opBIT(self, x):
        tbyte = self.ByteAt(x())
        self.p &=~(self.ZERO+self.NEGATIVE+self.OVERFLOW)
        if (self.a & tbyte) == 0:
            self.p |= self.ZERO
        self.p |= tbyte&(self.NEGATIVE+self.OVERFLOW)

    def opROL(self, x):
        if x is None:
            tbyte = self.a
        else:
            addr = x()
            tbyte = self.ByteAt(addr)

        if self.p & self.CARRY:
            if tbyte & self.NEGATIVE:
                pass
            else:
                self.p &= ~self.CARRY
            tbyte = (tbyte << 1) | 1
        else:
            if tbyte & self.NEGATIVE:
                self.p |= self.CARRY
            tbyte = tbyte << 1
        tbyte &= self.byteMask
        self.FlagsNZ(tbyte)

        if x is None:
           self.a = tbyte
        else:
            self.memory[addr] = tbyte

    def opEOR(self, x):
        self.a ^= self.ByteAt(x())
        self.FlagsNZ(self.a)

    def opADC(self, x):
        data = self.ByteAt(x())

        if self.p & self.DECIMAL:
            halfcarry = 0
            decimalcarry = 0
            adjust0 = 0
            adjust1 = 0
            nibble0 = (data & 0xf) + (self.a & 0xf) + (self.p & self.CARRY)
            if nibble0 > 9:
                adjust0 = 6
                halfcarry = 1
            nibble1 = ((data >> 4) & 0xf) + ((self.a >> 4) & 0xf) + halfcarry
            if nibble1 > 9:
                adjust1 = 6
                decimalcarry = 1

            # the ALU outputs are not decimally adjusted
            nibble0 = nibble0 & 0xf
            nibble1 = nibble1 & 0xf
            aluresult = (nibble1 << 4) + nibble0

            # the final A contents will be decimally adjusted
            nibble0 = (nibble0 + adjust0) & 0xf
            nibble1 = (nibble1 + adjust1) & 0xf
            self.p &= ~(self.CARRY+self.OVERFLOW+self.NEGATIVE+self.ZERO)
            if aluresult == 0:
                self.p |= self.ZERO
            else:
                self.p |= aluresult & self.NEGATIVE
            if decimalcarry == 1:
                self.p |= self.CARRY
            if ( ~(self.a ^ data) & (self.a ^ aluresult) ) & self.NEGATIVE:
                self.p |= self.OVERFLOW
            self.a = (nibble1 << 4) + nibble0
        else:
            if self.p & self.CARRY:
                tmp = 1
            else:
                tmp = 0
            result = data + self.a + tmp
            self.p &= ~(self.CARRY+self.OVERFLOW+self.NEGATIVE+self.ZERO)
            if ( ~(self.a ^ data) & (self.a ^ result) ) & self.NEGATIVE:
                self.p |= self.OVERFLOW
            data = result
            if data > self.byteMask:
                self.p |= self.CARRY
                data &=self.byteMask
            if data == 0:
                self.p |= self.ZERO
            else:
                self.p |= data & self.NEGATIVE
            self.a = data

    def opROR(self, x):
        if x is None:
            tbyte = self.a
        else:
            addr=x()
            tbyte = self.ByteAt(addr)

        if self.p & self.CARRY:
            if tbyte & 1:
                pass # {}
            else:
                self.p &=~ self.CARRY
            tbyte=(tbyte>>1)|self.NEGATIVE
        else:
          if tbyte & 1:
              self.p |= self.CARRY
          tbyte=tbyte>>1
        self.FlagsNZ(tbyte)

        if x is None:
            self.a = tbyte
        else:
            self.memory[addr] = tbyte

    def opSTA(self, x):
        self.memory[x()] = self.a

    def opSTY(self, x):
        self.memory[x()] = self.y

    def opSTX(self, y):
        self.memory[y()] = self.x

    def opCMPR(self, get_address, register_value):
        tbyte = self.ByteAt(get_address())
        self.p &= ~(self.CARRY+self.ZERO+self.NEGATIVE)
        if register_value == tbyte:
            self.p |= self.CARRY + self.ZERO
        elif register_value > tbyte:
            self.p |= self.CARRY
        self.p |= (register_value - tbyte) & self.NEGATIVE

    def opSBC(self, x):
      data = self.ByteAt(x())

      if self.p & self.DECIMAL:
          halfcarry = 1
          decimalcarry = 0
          adjust0 = 0
          adjust1 = 0

          nibble0 = (self.a & 0xf) + (~data & 0xf) + (self.p & self.CARRY)
          if nibble0 <= 0xf:
              halfcarry = 0
              adjust0 = 10
          nibble1 = ((self.a >> 4) & 0xf) + ((~data >> 4) & 0xf) + halfcarry
          if nibble1 <= 0xf:
              adjust1 = 10 << 4

          # the ALU outputs are not decimally adjusted
          aluresult = self.a + (~data & self.byteMask) + (self.p & self.CARRY)
          if aluresult > self.byteMask:
              decimalcarry = 1
          aluresult &= self.byteMask

          # but the final result will be adjusted
          nibble0 = (aluresult + adjust0) & 0xf
          nibble1 = ((aluresult + adjust1) >> 4) & 0xf

          self.p &= ~(self.CARRY + self.ZERO + self.NEGATIVE + self.OVERFLOW)
          if aluresult == 0:
              self.p |= self.ZERO
          else:
              self.p |= aluresult & self.NEGATIVE
          if decimalcarry == 1:
              self.p |= self.CARRY
          if ( (self.a ^ data) & (self.a ^ aluresult) ) & self.NEGATIVE:
              self.p |= self.OVERFLOW
          self.a = (nibble1 << 4) + nibble0
      else:
          if self.p & self.CARRY:
              borrow = 0
          else:
              borrow = 1

          result = self.a + (~data & self.byteMask) + (self.p & self.CARRY)
          self.p &= ~(self.CARRY + self.ZERO + self.OVERFLOW + self.NEGATIVE)
          if ( (self.a ^ data) & (self.a ^ result) ) & self.NEGATIVE:
              self.p |= self.OVERFLOW
          data = result & self.byteMask
          if data == 0:
              self.p |= self.ZERO
          if result > self.byteMask:
              self.p |= self.CARRY
          self.p |= data & self.NEGATIVE
          self.a = data

    def opDECR(self, x):
        if x is None:
            tbyte = self.a
        else:
            addr = x()
            tbyte = self.ByteAt(addr)

        self.p &= ~(self.ZERO + self.NEGATIVE)
        tbyte = (tbyte - 1) & self.byteMask
        if tbyte:
            self.p |= tbyte & self.NEGATIVE
        else:
            self.p |= self.ZERO

        if x is None:
            self.a = tbyte
        else:
            self.memory[addr] = tbyte

    def opINCR(self, x):
        if x is None:
            tbyte = self.a
        else:
            addr = x()
            tbyte = self.ByteAt(addr)

        self.p &= ~(self.ZERO + self.NEGATIVE)
        tbyte = (tbyte + 1) & self.byteMask
        if tbyte:
            self.p |= tbyte & self.NEGATIVE
        else:
            self.p |= self.ZERO

        if x is None:
            self.a = tbyte
        else:
            self.memory[addr] = tbyte

    def opLDA(self, x):
        self.a = self.ByteAt(x())
        self.FlagsNZ(self.a)

    def opLDY(self, x):
        self.y = self.ByteAt(x())
        self.FlagsNZ(self.y)

    def opLDX(self, y):
        self.x = self.ByteAt(y())
        self.FlagsNZ(self.x)

    # instructions

    def inst_not_implemented(self):
        self.pc += 1

    instruct    = [inst_not_implemented] * 256
    cycletime   = [0] * 256
    extracycles = [0] * 256
    disassemble = [('???', 'imp')] * 256

    instruction = make_instruction_decorator(instruct, disassemble,
                                             cycletime, extracycles)

    @instruction(name="BRK", mode="imp", cycles=7)
    def inst_0x00(self):
        pc = (self.pc + 1) & self.addrMask # The pc has already been increased one
        self.stPushWord(pc)

        self.p |= self.BREAK
        self.stPush(self.p | self.BREAK | self.UNUSED)

        self.p |= self.INTERRUPT
        self.pc = self.WordAt(self.IrqTo)

    @instruction(name="ORA", mode="inx", cycles=6)
    def inst_0x01(self):
        self.opORA(self.IndirectXAddr)
        self.pc += 1

    @instruction(name="ORA", mode="zpg", cycles=3)
    def inst_0x05(self):
        self.opORA(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="ASL", mode="zpg", cycles=5)
    def inst_0x06(self):
        self.opASL(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="PHP", mode="imp", cycles=3)
    def inst_0x08(self):
        self.stPush(self.p | self.BREAK | self.UNUSED)

    @instruction(name="ORA", mode="imm", cycles=2)
    def inst_0x09(self):
        self.opORA(self.ProgramCounter)
        self.pc += 1

    @instruction(name="ASL", mode="acc", cycles=2)
    def inst_0x0a(self):
        self.opASL(None)

    @instruction(name="ORA", mode="abs", cycles=4)
    def inst_0x0d(self):
        self.opORA(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="ASL", mode="abs", cycles=6)
    def inst_0x0e(self):
        self.opASL(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BPL", mode="rel", cycles=2, extracycles=2)
    def inst_0x10(self):
        self.opBCL(self.NEGATIVE)

    @instruction(name="ORA", mode="iny", cycles=5, extracycles=1)
    def inst_0x11(self):
        self.opORA(self.IndirectYAddr)
        self.pc += 1

    @instruction(name="ORA", mode="zpx", cycles=4)
    def inst_0x15(self):
        self.opORA(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="ASL", mode="zpx", cycles=6)
    def inst_0x16(self):
        self.opASL(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="CLC", mode="imp", cycles=2)
    def inst_0x18(self):
        self.opCLR(self.CARRY)

    @instruction(name="ORA", mode="aby", cycles=4, extracycles=1)
    def inst_0x19(self):
        self.opORA(self.AbsoluteYAddr)
        self.pc += 2

    @instruction(name="ORA", mode="abx", cycles=4, extracycles=1)
    def inst_0x1d(self):
        self.opORA(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="ASL", mode="abx", cycles=7)
    def inst_0x1e(self):
        self.opASL(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="JSR", mode="abs", cycles=6)
    def inst_0x20(self):
        self.stPushWord((self.pc+1)&self.addrMask)
        self.pc=self.WordAt(self.pc)

    @instruction(name="AND", mode="inx", cycles=6)
    def inst_0x21(self):
        self.opAND(self.IndirectXAddr)
        self.pc += 1

    @instruction(name="BIT", mode="zpg", cycles=3)
    def inst_0x24(self):
        self.opBIT(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="AND", mode="zpg", cycles=3)
    def inst_0x25(self):
        self.opAND(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="ROL", mode="zpg", cycles=5)
    def inst_0x26(self):
        self.opROL(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="PLP", mode="imp", cycles=4)
    def inst_0x28(self):
        self.p = (self.stPop() | self.BREAK | self.UNUSED)

    @instruction(name="AND", mode="imm", cycles=2)
    def inst_0x29(self):
        self.opAND(self.ProgramCounter)
        self.pc += 1

    @instruction(name="ROL", mode="acc", cycles=2)
    def inst_0x2a(self):
        self.opROL(None)

    @instruction(name="BIT", mode="abs", cycles=4)
    def inst_0x2c(self):
        self.opBIT(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="AND", mode="abs", cycles=4)
    def inst_0x2d(self):
        self.opAND(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="ROL", mode="abs", cycles=6)
    def inst_0x2e(self):
        self.opROL(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BMI", mode="rel", cycles=2, extracycles=2)
    def inst_0x30(self):
        self.opBST(self.NEGATIVE)

    @instruction(name="AND", mode="iny", cycles=5, extracycles=1)
    def inst_0x31(self):
        self.opAND(self.IndirectYAddr)
        self.pc += 1

    @instruction(name="AND", mode="zpx", cycles=4)
    def inst_0x35(self):
        self.opAND(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="ROL", mode="zpx", cycles=6)
    def inst_0x36(self):
        self.opROL(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="SEC", mode="imp", cycles=2)
    def inst_0x38(self):
        self.opSET(self.CARRY)

    @instruction(name="AND", mode="aby", cycles=4, extracycles=1)
    def inst_0x39(self):
        self.opAND(self.AbsoluteYAddr)
        self.pc += 2

    @instruction(name="AND", mode="abx", cycles=4, extracycles=1)
    def inst_0x3d(self):
        self.opAND(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="ROL", mode="abx", cycles=7)
    def inst_0x3e(self):
        self.opROL(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="RTI", mode="imp", cycles=6)
    def inst_0x40(self):
        self.p = (self.stPop() | self.BREAK | self.UNUSED)
        self.pc = self.stPopWord()

    @instruction(name="EOR", mode="inx", cycles=6)
    def inst_0x41(self):
        self.opEOR(self.IndirectXAddr)
        self.pc += 1

    @instruction(name="EOR", mode="zpg", cycles=3)
    def inst_0x45(self):
        self.opEOR(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="LSR", mode="zpg", cycles=5)
    def inst_0x46(self):
        self.opLSR(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="PHA", mode="imp", cycles=3)
    def inst_0x48(self):
        self.stPush(self.a)

    @instruction(name="EOR", mode="imm", cycles=2)
    def inst_0x49(self):
        self.opEOR(self.ProgramCounter)
        self.pc += 1

    @instruction(name="LSR", mode="acc", cycles=2)
    def inst_0x4a(self):
        self.opLSR(None)

    @instruction(name="JMP", mode="abs", cycles=3)
    def inst_0x4c(self):
        self.pc=self.WordAt(self.pc)

    @instruction(name="EOR", mode="abs", cycles=4)
    def inst_0x4d(self):
        self.opEOR(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="LSR", mode="abs", cycles=6)
    def inst_0x4e(self):
        self.opLSR(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BVC", mode="rel", cycles=2, extracycles=2)
    def inst_0x50(self):
        self.opBCL(self.OVERFLOW)

    @instruction(name="EOR", mode="iny", cycles=5, extracycles=1)
    def inst_0x51(self):
        self.opEOR(self.IndirectYAddr)
        self.pc += 1

    @instruction(name="EOR", mode="zpx", cycles=4)
    def inst_0x55(self):
        self.opEOR(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="LSR", mode="zpx", cycles=6)
    def inst_0x56(self):
        self.opLSR(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="CLI", mode="imp", cycles=2)
    def inst_0x58(self):
        self.opCLR(self.INTERRUPT)

    @instruction(name="EOR", mode="aby", cycles=4, extracycles=1)
    def inst_0x59(self):
        self.opEOR(self.AbsoluteYAddr)
        self.pc +=2

    @instruction(name="EOR", mode="abx", cycles=4, extracycles=1)
    def inst_0x5d(self):
        self.opEOR(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="LSR", mode="abx", cycles=7)
    def inst_0x5e(self):
        self.opLSR(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="RTS", mode="imp", cycles=6)
    def inst_0x60(self):
        self.pc=self.stPopWord()
        self.pc += 1

    @instruction(name="ADC", mode="inx", cycles=6)
    def inst_0x61(self):
        self.opADC(self.IndirectXAddr)
        self.pc += 1

    @instruction(name="ADC", mode="zpg", cycles=3)
    def inst_0x65(self):
        self.opADC(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="ROR", mode="zpg", cycles=5)
    def inst_0x66(self):
        self.opROR(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="PLA", mode="imp", cycles=4)
    def inst_0x68(self):
        self.a = self.stPop()
        self.FlagsNZ(self.a)

    @instruction(name="ADC", mode="imm", cycles=2)
    def inst_0x69(self):
        self.opADC(self.ProgramCounter)
        self.pc += 1

    @instruction(name="ROR", mode="acc", cycles=2)
    def inst_0x6a(self):
        self.opROR(None)

    @instruction(name="JMP", mode="ind", cycles=5)
    def inst_0x6c(self):
        ta = self.WordAt(self.pc)
        self.pc = self.WrapAt(ta)

    @instruction(name="ADC", mode="abs", cycles=4)
    def inst_0x6d(self):
        self.opADC(self.AbsoluteAddr)
        self.pc +=2

    @instruction(name="ROR", mode="abs", cycles=6)
    def inst_0x6e(self):
        self.opROR(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BVS", mode="rel", cycles=2, extracycles=2)
    def inst_0x70(self):
        self.opBST(self.OVERFLOW)

    @instruction(name="ADC", mode="iny", cycles=5, extracycles=1)
    def inst_0x71(self):
        self.opADC(self.IndirectYAddr)
        self.pc += 1

    @instruction(name="ADC", mode="zpx", cycles=4)
    def inst_0x75(self):
        self.opADC(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="ROR", mode="zpx", cycles=6)
    def inst_0x76(self):
        self.opROR(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="SEI", mode="imp", cycles=2)
    def inst_0x78(self):
        self.opSET(self.INTERRUPT)

    @instruction(name="ADC", mode="aby", cycles=4, extracycles=1)
    def inst_0x79(self):
        self.opADC(self.AbsoluteYAddr)
        self.pc += 2

    @instruction(name="ADC", mode="abx", cycles=4, extracycles=1)
    def inst_0x7d(self):
        self.opADC(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="ROR", mode="abx", cycles=7)
    def inst_0x7e(self):
        self.opROR(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="STA", mode="inx", cycles=6)
    def inst_0x81(self):
        self.opSTA(self.IndirectXAddr)
        self.pc += 1

    @instruction(name="STY", mode="zpg", cycles=3)
    def inst_0x84(self):
        self.opSTY(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="STA", mode="zpg", cycles=3)
    def inst_0x85(self):
        self.opSTA(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="STX", mode="zpg", cycles=3)
    def inst_0x86(self):
        self.opSTX(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="DEY", mode="imp", cycles=2)
    def inst_0x88(self):
        self.y -= 1
        self.y&=self.byteMask
        self.FlagsNZ(self.y)

    @instruction(name="TXA", mode="imp", cycles=2)
    def inst_0x8a(self):
        self.a=self.x
        self.FlagsNZ(self.a)

    @instruction(name="STY", mode="abs", cycles=4)
    def inst_0x8c(self):
        self.opSTY(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="STA", mode="abs", cycles=4)
    def inst_0x8d(self):
        self.opSTA(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="STX", mode="abs", cycles=4)
    def inst_0x8e(self):
        self.opSTX(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BCC", mode="rel", cycles=2, extracycles=2)
    def inst_0x90(self):
        self.opBCL(self.CARRY)

    @instruction(name="STA", mode="iny", cycles=6)
    def inst_0x91(self):
        self.opSTA(self.IndirectYAddr)
        self.pc += 1

    @instruction(name="STY", mode="zpx", cycles=4)
    def inst_0x94(self):
        self.opSTY(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="STA", mode="zpx", cycles=4)
    def inst_0x95(self):
        self.opSTA(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="STX", mode="zpy", cycles=4)
    def inst_0x96(self):
        self.opSTX(self.ZeroPageYAddr)
        self.pc += 1

    @instruction(name="TYA", mode="imp", cycles=2)
    def inst_0x98(self):
        self.a = self.y
        self.FlagsNZ(self.a)

    @instruction(name="STA", mode="aby", cycles=5)
    def inst_0x99(self):
        self.opSTA(self.AbsoluteYAddr)
        self.pc += 2

    @instruction(name="TXS", mode="imp", cycles=2)
    def inst_0x9a(self):
        self.sp=self.x

    @instruction(name="STA", mode="abx", cycles=5)
    def inst_0x9d(self):
        self.opSTA(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="LDY", mode="imm", cycles=2)
    def inst_0xa0(self):
        self.opLDY(self.ProgramCounter)
        self.pc += 1

    @instruction(name="LDA", mode="inx", cycles=6)
    def inst_0xa1(self):
        self.opLDA(self.IndirectXAddr)
        self.pc += 1

    @instruction(name="LDX", mode="imm", cycles=2)
    def inst_0xa2(self):
        self.opLDX(self.ProgramCounter)
        self.pc += 1

    @instruction(name="LDY", mode="zpg", cycles=3)
    def inst_0xa4(self):
        self.opLDY(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="LDA", mode="zpg", cycles=3)
    def inst_0xa5(self):
        self.opLDA(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="LDX", mode="zpg", cycles=3)
    def inst_0xa6(self):
        self.opLDX(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="TAY", mode="imp", cycles=2)
    def inst_0xa8(self):
        self.y = self.a
        self.FlagsNZ(self.y)

    @instruction(name="LDA", mode="imm", cycles=2)
    def inst_0xa9(self):
        self.opLDA(self.ProgramCounter)
        self.pc += 1

    @instruction(name="TAX", mode="imp", cycles=2)
    def inst_0xaa(self):
        self.x = self.a
        self.FlagsNZ(self.x)

    @instruction(name="LDY", mode="abs", cycles=4)
    def inst_0xac(self):
        self.opLDY(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="LDA", mode="abs", cycles=4)
    def inst_0xad(self):
        self.opLDA(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="LDX", mode="abs", cycles=4)
    def inst_0xae(self):
        self.opLDX(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BCS", mode="rel", cycles=2, extracycles=2)
    def inst_0xb0(self):
        self.opBST(self.CARRY)

    @instruction(name="LDA", mode="iny", cycles=5, extracycles=1)
    def inst_0xb1(self):
        self.opLDA(self.IndirectYAddr)
        self.pc += 1

    @instruction(name="LDY", mode="zpx", cycles=4)
    def inst_0xb4(self):
        self.opLDY(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="LDA", mode="zpx", cycles=4)
    def inst_0xb5(self):
        self.opLDA(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="LDX", mode="zpy", cycles=4)
    def inst_0xb6(self):
        self.opLDX(self.ZeroPageYAddr)
        self.pc += 1

    @instruction(name="CLV", mode="imp", cycles=2)
    def inst_0xb8(self):
        self.opCLR(self.OVERFLOW)

    @instruction(name="LDA", mode="aby", cycles=4, extracycles=1)
    def inst_0xb9(self):
        self.opLDA(self.AbsoluteYAddr)
        self.pc += 2

    @instruction(name="TSX", mode="imp", cycles=2)
    def inst_0xba(self):
        self.x = self.sp
        self.FlagsNZ(self.x)

    @instruction(name="LDY", mode="abx", cycles=4, extracycles=1)
    def inst_0xbc(self):
        self.opLDY(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="LDA", mode="abx", cycles=4, extracycles=1)
    def inst_0xbd(self):
        self.opLDA(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="LDX", mode="aby", cycles=4, extracycles=1)
    def inst_0xbe(self):
        self.opLDX(self.AbsoluteYAddr)
        self.pc += 2

    @instruction(name="CPY", mode="imm", cycles=2)
    def inst_0xc0(self):
        self.opCMPR(self.ProgramCounter, self.y)
        self.pc += 1

    @instruction(name="CMP", mode="inx", cycles=6)
    def inst_0xc1(self):
        self.opCMPR(self.IndirectXAddr, self.a)
        self.pc += 1

    @instruction(name="CPY", mode="zpg", cycles=3)
    def inst_0xc4(self):
        self.opCMPR(self.ZeroPageAddr, self.y)
        self.pc += 1

    @instruction(name="CMP", mode="zpg", cycles=3)
    def inst_0xc5(self):
        self.opCMPR(self.ZeroPageAddr, self.a)
        self.pc += 1

    @instruction(name="DEC", mode="zpg", cycles=5)
    def inst_0xc6(self):
        self.opDECR(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="INY", mode="imp", cycles=2)
    def inst_0xc8(self):
        self.y += 1
        self.y &= self.byteMask
        self.FlagsNZ(self.y)

    @instruction(name="CMP", mode="imm", cycles=2)
    def inst_0xc9(self):
        self.opCMPR(self.ProgramCounter, self.a)
        self.pc +=1

    @instruction(name="DEX", mode="imp", cycles=2)
    def inst_0xca(self):
        self.x -= 1
        self.x &= self.byteMask
        self.FlagsNZ(self.x)

    @instruction(name="CPY", mode="abs", cycles=4)
    def inst_0xcc(self):
        self.opCMPR(self.AbsoluteAddr, self.y)
        self.pc += 2

    @instruction(name="CMP", mode="abs", cycles=4)
    def inst_0xcd(self):
        self.opCMPR(self.AbsoluteAddr, self.a)
        self.pc += 2

    @instruction(name="DEC", mode="abs", cycles=3)
    def inst_0xce(self):
        self.opDECR(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BNE", mode="rel", cycles=2, extracycles=2)
    def inst_0xd0(self):
        self.opBCL(self.ZERO)

    @instruction(name="CMP", mode="iny", cycles=5, extracycles=1)
    def inst_0xd1(self):
        self.opCMPR(self.IndirectYAddr, self.a)
        self.pc += 1

    @instruction(name="CMP", mode="zpx", cycles=4)
    def inst_0xd5(self):
        self.opCMPR(self.ZeroPageXAddr, self.a)
        self.pc += 1

    @instruction(name="DEC", mode="zpx", cycles=6)
    def inst_0xd6(self):
        self.opDECR(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="CLD", mode="imp", cycles=2)
    def inst_0xd8(self):
        self.opCLR(self.DECIMAL)

    @instruction(name="CMP", mode="aby", cycles=4, extracycles=1)
    def inst_0xd9(self):
        self.opCMPR(self.AbsoluteYAddr, self.a)
        self.pc += 2

    @instruction(name="CMP", mode="abx", cycles=4, extracycles=1)
    def inst_0xdd(self):
        self.opCMPR(self.AbsoluteXAddr, self.a)
        self.pc += 2

    @instruction(name="DEC", mode="abx", cycles=7)
    def inst_0xde(self):
        self.opDECR(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="CPX", mode="imm", cycles=2)
    def inst_0xe0(self):
        self.opCMPR(self.ProgramCounter, self.x)
        self.pc += 1

    @instruction(name="SBC", mode="inx", cycles=6)
    def inst_0xe1(self):
        self.opSBC(self.IndirectXAddr)
        self.pc += 1

    @instruction(name="CPX", mode="zpg", cycles=3)
    def inst_0xe4(self):
        self.opCMPR(self.ZeroPageAddr, self.x)
        self.pc += 1

    @instruction(name="SBC", mode="zpg", cycles=3)
    def inst_0xe5(self):
        self.opSBC(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="INC", mode="zpg", cycles=5)
    def inst_0xe6(self):
        self.opINCR(self.ZeroPageAddr)
        self.pc += 1

    @instruction(name="INX", mode="imp", cycles=2)
    def inst_0xe8(self):
        self.x+=1
        self.x&=self.byteMask
        self.FlagsNZ(self.x)

    @instruction(name="SBC", mode="imm", cycles=2)
    def inst_0xe9(self):
        self.opSBC(self.ProgramCounter)
        self.pc += 1

    @instruction(name="NOP", mode="imp", cycles=2)
    def inst_0xea(self):
        pass

    @instruction(name="CPX", mode="abs", cycles=4)
    def inst_0xec(self):
        self.opCMPR(self.AbsoluteAddr, self.x)
        self.pc += 2

    @instruction(name="SBC", mode="abs", cycles=4)
    def inst_0xed(self):
        self.opSBC(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="INC", mode="abs", cycles=6)
    def inst_0xee(self):
        self.opINCR(self.AbsoluteAddr)
        self.pc += 2

    @instruction(name="BEQ", mode="rel", cycles=2, extracycles=2)
    def inst_0xf0(self):
        self.opBST(self.ZERO)

    @instruction(name="SBC", mode="iny", cycles=5, extracycles=1)
    def inst_0xf1(self):
        self.opSBC(self.IndirectYAddr)
        self.pc += 1

    @instruction(name="SBC", mode="zpx", cycles=4)
    def inst_0xf5(self):
        self.opSBC(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="INC", mode="zpx", cycles=6)
    def inst_0xf6(self):
        self.opINCR(self.ZeroPageXAddr)
        self.pc += 1

    @instruction(name="SED", mode="imp", cycles=2)
    def inst_0xf8(self):
        self.opSET(self.DECIMAL)

    @instruction(name="SBC", mode="aby", cycles=4, extracycles=1)
    def inst_0xf9(self):
        self.opSBC(self.AbsoluteYAddr)
        self.pc += 2

    @instruction(name="SBC", mode="abx", cycles=4, extracycles=1)
    def inst_0xfd(self):
        self.opSBC(self.AbsoluteXAddr)
        self.pc += 2

    @instruction(name="INC", mode="abx", cycles=7)
    def inst_0xfe(self):
        self.opINCR(self.AbsoluteXAddr)
        self.pc += 2