riscemu.MMU module

RiscEmu (c) 2021 Anton Lydike

SPDX-License-Identifier: MIT

class riscemu.MMU.MMU(conf: riscemu.Config.RunConfig)

Bases: object

The MemoryManagementUnit (handles loading binaries, and reading/writing data)

max_size = 4294967295

The maximum size of the memory in bytes

max_alloc_size = 536870912

No single allocation can be bigger than 64 MB

last_bin: Optional[riscemu.Executable.LoadedExecutable] = None

The last loaded executable (the next executable is inserted directly after this one)

__init__(conf: riscemu.Config.RunConfig)

Create a new MMU, respeccting the active RunConfiguration

Parameters

conf – The config to respect

sections: List[riscemu.Executable.LoadedMemorySection]

A list of all loaded memory sections

binaries: List[riscemu.Executable.LoadedExecutable]

A list of all loaded executables

global_symbols: Dict[str, int]

The global symbol table

load_bin(exe: riscemu.Executable.Executable) → riscemu.Executable.LoadedExecutable

Load an executable into memory

Parameters

exe – the executable to load

Returns

A LoadedExecutable

Raises

OutOfMemoryException – When all memory is used

allocate_section(name: str, req_size: int, flag: riscemu.Executable.MemoryFlags)

Used to allocate a memory region (data only). Use load_bin if you want to load a binary, this is used for stack and maybe malloc in the future.

Parameters

  • name – Name of the section to allocate

  • req_size – The requested size

  • flag – The flags protecting this memory section

Returns

The LoadedMemorySection

get_sec_containing(addr: int) → Optional[riscemu.Executable.LoadedMemorySection]

Returns the section that contains the address addr

Parameters

addr – the Address to look for

Returns

The LoadedMemorySection or None

get_bin_containing(addr: int) → Optional[riscemu.Executable.LoadedExecutable]
read_ins(addr: int) → riscemu.Executable.LoadedInstruction

Read a single instruction located at addr

Parameters

addr – The location

Returns

The Instruction

read(addr: int, size: int) → bytearray

Read size bytes of memory at addr

Parameters

  • addr – The addres at which to start reading

  • size – The number of bytes to read

Returns

The bytearray at addr

write(addr: int, size: int, data)

Write bytes into memory

Parameters

  • addr – The address at which to write

  • size – The number of bytes to write

  • data – The bytearray to write (only first size bytes are written)

dump(addr, *args, **kwargs)

Dumpy the memory contents

Parameters

  • addr – The address at which to dump

  • args – args for the dump function of the loaded memory section

  • kwargs – kwargs for the dump function of the loaded memory section

symbol(symb: str)

Look up the symbol symb in all local symbol tables (and the global one)

Parameters

symb – The symbol name to look up