list(pyboy.memory) hangs process

[pichenka007gd]

Memory Dump Hang During Full Memory Comparison

For emulator testing against real hardware behavior, I'm comparing my emulator's execution with PyBoy using a test script that validates CPU instructions.

Problem Description

• Initially, I compared only CPU registers cycle-to-cycle
• Discovered desync issues during 0xF0: LDH A,(a8) instruction where my memory values diverge
• Switched to full memory comparison for better accuracy:

  gbi_ram = list(gbi.pyboy.memory)
  gb_ram = [gb.memory.read_byte(i) for i in range(0xFFFF)]
  assert gbi_ram == gb_ram

Current Issue

When trying to dump full memory space (0x0000-0xFFFF):

• ist(gbi.pyboy.memory) and similar approaches hang at "phantom addresses" (e.g., 0xFC12, 0xFE12)
• Process consumes excessive RAM before freezing
• Same issue occurs with list(gbi.pyboy.mb)
• PyBoy's built-in save_state() doesn't provide raw memory access needed for comparison

Specific Challenges

• Need to access memory with current bank selection state
• Must handle hardware-mirrored regions properly
• Avoid memory leaks/hangs during iteration
• Get raw byte values (not state-serialized format)

How to properly:

• Iterate full memory space (0x0000-0xFFFF) respecting current memory banking
• Obtain raw byte values without triggering interrupt

Thank you!

[Baekalfen]

I see there is a bug when calling list(pyboy.memory), which shouldn't hang the program. I hadn't anticipated that use. But until that, you can do a list-comprehension like you do with your emulator

[pichenka007gd]

Thank you for your reply.
If you mean the structure [pyboy.memory[i] for i in range(0xFFFF)], it also hangs on some addresses just like list.
This happens because the list comprehension iterates over all indices if the object supports accessing values by index.
Apparently, when accessing a value, some kind of address handler is triggered

[Baekalfen]

I cannot reproduce that [pyboy.memory[i] for i in range(0xFFFF)] hangs. Which address does it hang on?

The problem with list(...) is that it's unbounded. PyBoy has no attribute to tell it the size of the memory space.

[pichenka007gd]

yo
umm I'm here (yeah after a 2 weeks) uploaded my repository and...
this bug no longer exists
maybe it's because you made some changes during these 2 weeks or it was Python environment issues on my phone
I think this issue can be closed
thanks, good luck

[Baekalfen]

You must have changed something, because I didn't fix it. I still have a test case that can reproduce it. Bad news is, that I won't support doing list(pyboy.memory) for now anyway, as it's more complicated than just a flat list. Instead it will raise an exception.