import

qemu/target-mips/TODO

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+Unsolved issues/bugs in the mips/mipsel backend
+-----------------------------------------------
+
+General
+-------
+- Unimplemented ASEs:
+  - MDMX
+  - SmartMIPS
+  - microMIPS DSP r1 & r2 encodings
+- MT ASE only partially implemented and not functional
+- Shadow register support only partially implemented,
+  lacks set switching on interrupt/exception.
+- 34K ITC not implemented.
+- A general lack of documentation, especially for technical internals.
+  Existing documentation is x86-centric.
+- Reverse endianness bit not implemented
+- The TLB emulation is very inefficient:
+  QEMU's softmmu implements a x86-style MMU, with separate entries
+  for read/write/execute, a TLB index which is just a modulo of the
+  virtual address, and a set of TLBs for each user/kernel/supervisor
+  MMU mode.
+  MIPS has a single entry for read/write/execute and only one MMU mode.
+  But it is fully associative with randomized entry indices, and uses
+  up to 256 ASID tags as additional matching criterion (which roughly
+  equates to 256 MMU modes). It also has a global flag which causes
+  entries to match regardless of ASID.
+  To cope with these differences, QEMU currently flushes the TLB at
+  each ASID change. Using the MMU modes to implement ASIDs hinges on
+  implementing the global bit efficiently.
+- save/restore of the CPU state is not implemented (see machine.c).
+
+MIPS64
+------
+- Userland emulation (both n32 and n64) not functional.
+
+"Generic" 4Kc system emulation
+------------------------------
+- Doesn't correspond to any real hardware. Should be removed some day,
+  U-Boot is the last remaining user.
+
+PICA 61 system emulation
+------------------------
+- No framebuffer support yet.
+
+MALTA system emulation
+----------------------
+- We fake firmware support instead of doing the real thing
+- Real firmware (YAMON) falls over when trying to init RAM, presumably
+  due to lacking system controller emulation.
+- Bonito system controller not implemented
+- MSC1 system controller not implemented