A MOS 6502 Emulator intended to be used from within other programs. All opcodes, included the undocumented illegal opcodes are implemented.

Example Usage::

from py65emu.cpu import CPU
from py65emu.mmu import MMU

f = open("program.rom", "rb")  # Open your rom

# define your blocks of memory.  Each tuple is
# (start_address, length, readonly=True, initial_value=None, value_offset=0)
m = MMU([
        (0x00, 0x200), # Create RAM with 512 bytes
        (0x1000, 0x4000, True, f) # Create ROM starting at 0x1000 with your program.
])

# Create the CPU with the MMU and the starting program counter address
# You can also optionally pass in a value for stack_page, which defaults
# to 1, meaning the stack will be from 0x100-0x1ff.  As far as I know this
# is true for all 6502s, but for instance in the 6507 used by the Atari
# 2600 it is in the zero page, stack_page=0.
c = CPU(mmu, 0x1000)

# Do this to execute one instruction
c.step()

# You can check the registers and memory values to determine what has changed
print c.r.a     # A register
print c.r.x     # X register
print c.r.y     # Y register
print c.r.s     # Stack Pointer
print c.r.pc    # Program Counter

print c.r.getFlag('C') # Get the value of a flag from the flag register.

print mmu.read(0xff) # Read a value from memory