Implement Random RAM

pyboy/__main__.py

@@ -36,6 +36,7 @@ def valid_file_path(path):
 parser.add_argument("ROM", type=valid_file_path, help="Path to a Game Boy compatible ROM file")
 parser.add_argument("-b", "--bootrom", type=valid_file_path, help="Path to a boot-ROM file")
 parser.add_argument("--profiling", action="store_true", help="Enable opcode profiling (internal use)")
+parser.add_argument("--randomize-ram", action="store_true", help="Randomize Game Boy RAM on startup")
 parser.add_argument(
     "--log-level",
     default="INFO",

pyboy/core/lcd.py

@@ -5,6 +5,7 @@
 
 from array import array
 from ctypes import c_void_p
+from random import getrandbits
 
 from pyboy.utils import color_code
 
@@ -22,7 +23,7 @@
 
 
 class LCD:
-    def __init__(self):
+    def __init__(self, randomize=False):
         self.VRAM = array("B", [0] * VIDEO_RAM)
         self.OAM = array("B", [0] * OBJECT_ATTRIBUTE_MEMORY)
 
@@ -39,6 +40,12 @@ def __init__(self):
         self.WY = 0x00
         self.WX = 0x00
 
+        if randomize:
+            for i in range(VIDEO_RAM):
+                self.VRAM[i] = getrandbits(8)
+            for i in range(OBJECT_ATTRIBUTE_MEMORY):
+                self.OAM[i] = getrandbits(8)
+
     def save_state(self, f):
         for n in range(VIDEO_RAM):
             f.write(self.VRAM[n])

pyboy/core/mb.py

@@ -16,7 +16,8 @@
 
 
 class Motherboard:
-    def __init__(self, gamerom_file, bootrom_file, color_palette, disable_renderer, sound_enabled, profiling=False):
+    def __init__(self, gamerom_file, bootrom_file, color_palette, disable_renderer, sound_enabled, randomize=False,
+                 profiling=False):
         if bootrom_file is not None:
             logger.info("Boot-ROM file provided")
 
@@ -27,9 +28,9 @@ def __init__(self, gamerom_file, bootrom_file, color_palette, disable_renderer,
         self.interaction = interaction.Interaction()
         self.cartridge = cartridge.load_cartridge(gamerom_file)
         self.bootrom = bootrom.BootROM(bootrom_file)
-        self.ram = ram.RAM(random=False)
+        self.ram = ram.RAM(randomize=randomize)
         self.cpu = cpu.CPU(self, profiling)
-        self.lcd = lcd.LCD()
+        self.lcd = lcd.LCD(randomize=randomize)
         self.renderer = lcd.Renderer(color_palette)
         self.disable_renderer = disable_renderer
         self.sound_enabled = sound_enabled

pyboy/core/ram.py

@@ -3,10 +3,11 @@
 # GitHub: https://github.com/Baekalfen/PyBoy
 #
 
-import array
+from array import array
+from random import getrandbits
 
 # MEMORY SIZES
-INTERNAL_RAM0 = 8 * 1024 # 8KB
+INTERNAL_RAM0 = 8 * 1024 # 8KiB
 NON_IO_INTERNAL_RAM0 = 0x60
 IO_PORTS = 0x4C
 NON_IO_INTERNAL_RAM1 = 0x34
@@ -15,16 +16,23 @@
 
 
 class RAM:
-    def __init__(self, random=False):
-        if random: # NOTE: In real life, the RAM is scrambled with random data on boot.
-            raise Exception("Random RAM not implemented")
+    def __init__(self, randomize=False):
+        self.internal_ram0 = array("B", [0] * (INTERNAL_RAM0))
+        self.non_io_internal_ram0 = array("B", [0] * (NON_IO_INTERNAL_RAM0))
+        self.io_ports = array("B", [0] * (IO_PORTS))
+        self.internal_ram1 = array("B", [0] * (INTERNAL_RAM1))
+        self.non_io_internal_ram1 = array("B", [0] * (NON_IO_INTERNAL_RAM1))
+        self.interrupt_register = array("B", [0] * (INTERRUPT_ENABLE_REGISTER))
 
-        self.internal_ram0 = array.array("B", [0] * (INTERNAL_RAM0))
-        self.non_io_internal_ram0 = array.array("B", [0] * (NON_IO_INTERNAL_RAM0))
-        self.io_ports = array.array("B", [0] * (IO_PORTS))
-        self.internal_ram1 = array.array("B", [0] * (INTERNAL_RAM1))
-        self.non_io_internal_ram1 = array.array("B", [0] * (NON_IO_INTERNAL_RAM1))
-        self.interrupt_register = array.array("B", [0] * (INTERRUPT_ENABLE_REGISTER))
+        if randomize:
+            for i in range(INTERNAL_RAM0):
+                self.internal_ram0[i] = getrandbits(8)
+            for i in range(NON_IO_INTERNAL_RAM0):
+                self.non_io_internal_ram0[i] = getrandbits(8)
+            for i in range(INTERNAL_RAM1):
+                self.internal_ram1[i] = getrandbits(8)
+            for i in range(NON_IO_INTERNAL_RAM1):
+                self.non_io_internal_ram1[i] = getrandbits(8)
 
     def save_state(self, f):
         for n in range(INTERNAL_RAM0):

pyboy/pyboy.py

@@ -30,7 +30,8 @@
 
 class PyBoy:
     def __init__(
-        self, gamerom_file, *, bootrom_file=None, profiling=False, disable_renderer=False, sound=False, **kwargs
+            self, gamerom_file, *, bootrom_file=None, profiling=False, disable_renderer=False, sound=False,
+            randomize=False, **kwargs
     ):
         """
         PyBoy is loadable as an object in Python. This means, it can be initialized from another script, and be
@@ -70,6 +71,7 @@ def __init__(
             kwargs["color_palette"],
             disable_renderer,
             sound,
+            randomize=randomize,
             profiling=profiling,
         )
 

tests/test_basics.py

@@ -170,3 +170,25 @@ def test_tilemaps():
     assert isinstance(wdw_tilemap[0, 0], Tile)
 
     pyboy.stop(save=False)
+
+
+def test_randomize_ram():
+    pyboy = PyBoy(default_rom) # randomize=False, by default
+    # RAM banks should all be 0 by default
+    assert not any([pyboy.get_memory_value(x) for x in range(0x8000, 0xA000)]), "VRAM not zeroed"
+    assert not any([pyboy.get_memory_value(x) for x in range(0xC000, 0xE000)]), "Internal RAM 0 not zeroed"
+    assert not any([pyboy.get_memory_value(x) for x in range(0xFE00, 0xFEA0)]), "OAM not zeroed"
+    assert not any([pyboy.get_memory_value(x) for x in range(0xFEA0, 0xFF00)]), "Non-IO internal RAM 0 not zeroed"
+    assert not any([pyboy.get_memory_value(x) for x in range(0xFF4C, 0xFF80)]), "Non-IO internal RAM 1 not zeroed"
+    assert not any([pyboy.get_memory_value(x) for x in range(0xFF80, 0xFFFF)]), "Internal RAM 1 not zeroed"
+    pyboy.stop(save=False)
+
+    pyboy = PyBoy(default_rom, randomize=True)
+    # RAM banks should have nonzero values now
+    assert any([pyboy.get_memory_value(x) for x in range(0x8000, 0xA000)]), "VRAM not randomized"
+    assert any([pyboy.get_memory_value(x) for x in range(0xC000, 0xE000)]), "Internal RAM 0 not randomized"
+    assert any([pyboy.get_memory_value(x) for x in range(0xFE00, 0xFEA0)]), "OAM not randomized"
+    assert any([pyboy.get_memory_value(x) for x in range(0xFEA0, 0xFF00)]), "Non-IO internal RAM 0 not randomized"
+    assert any([pyboy.get_memory_value(x) for x in range(0xFF4C, 0xFF80)]), "Non-IO internal RAM 1 not randomized"
+    assert any([pyboy.get_memory_value(x) for x in range(0xFF80, 0xFFFF)]), "Internal RAM 1 not randomized"
+    pyboy.stop(save=False)

tests/test_replay.py

@@ -72,7 +72,8 @@ def replay(
     rewind=False,
     bootrom_file=utils.boot_rom,
     overwrite=RESET_REPLAYS,
-    gif_hash=None
+    gif_hash=None,
+    randomize=False
 ):
     with open(replay, "rb") as f:
         recorded_input, b64_romhash, b64_state = json.loads(zlib.decompress(f.read()).decode("ascii"))
@@ -86,6 +87,7 @@ def replay(
         bootrom_file=bootrom_file,
         disable_input=True,
         rewind=rewind,
+        randomize=randomize,
         record_input=(RESET_REPLAYS and window in ["SDL2", "headless", "OpenGL"])
     )
     pyboy.set_emulation_speed(0)
@@ -187,7 +189,8 @@ def test_supermarioland_gif():
         "tests/replays/supermarioland_gif.replay",
         record_gif=(122, 644),
         gif_destination="README/3.gif",
-        gif_hash="15aVUmwtTq38E3SB91moQLYSTZVWuTNTUmzYVSgTg38="
+        gif_hash="15aVUmwtTq38E3SB91moQLYSTZVWuTNTUmzYVSgTg38=",
+        randomize=True
     )