projects / qemu.git / blame
| Commit | Line | Data |
|---|---|---|
| 2c52c816 TS |
1 | Unsolved issues/bugs in the mips/mipsel backend |
| 2 | ----------------------------------------------- | |
| 3 | ||
| 15dcf5aa TS |
4 | General |
| 5 | ------- | |
| d0f48074 | 6 | - Unimplemented ASEs: |
| d0f48074 TS |
7 | - MDMX |
| 8 | - SmartMIPS | |
| 9 | - DSP r1 | |
| 10 | - DSP r2 | |
| 11 | - MT ASE only partially implemented and not functional | |
| 12 | - Shadow register support only partially implemented, | |
| 13 | lacks set switching on interrupt/exception. | |
| 14 | - 34K ITC not implemented. | |
| 15 | - A general lack of documentation, especially for technical internals. | |
| 16 | Existing documentation is x86-centric. | |
| 17 | - Reverse endianness bit not implemented | |
| 18 | - The TLB emulation is very inefficient: | |
| 19 | Qemu's softmmu implements a x86-style MMU, with separate entries | |
| 20 | for read/write/execute, a TLB index which is just a modulo of the | |
| 21 | virtual address, and a set of TLBs for each user/kernel/supervisor | |
| 22 | MMU mode. | |
| 23 | MIPS has a single entry for read/write/execute and only one MMU mode. | |
| 24 | But it is fully associative with randomized entry indices, and uses | |
| 25 | up to 256 ASID tags as additional matching criterion (which roughly | |
| 26 | equates to 256 MMU modes). It also has a global flag which causes | |
| 27 | entries to match regardless of ASID. | |
| 28 | To cope with these differences, Qemu currently flushes the TLB at | |
| 29 | each ASID change. Using the MMU modes to implement ASIDs hinges on | |
| 30 | implementing the global bit efficiently. | |
| bec19c09 | 31 | - save/restore of the CPU state is not implemented (see machine.c). |
| 2c52c816 | 32 | |
| 15dcf5aa TS |
33 | MIPS64 |
| 34 | ------ | |
| 540635ba | 35 | - Userland emulation (both n32 and n64) not functional. |
| 15dcf5aa TS |
36 | |
| 37 | "Generic" 4Kc system emulation | |
| 38 | ------------------------------ | |
| ebbd0ffd TS |
39 | - Doesn't correspond to any real hardware. Should be removed some day, |
| 40 | U-Boot is the last remaining user. | |
| 15dcf5aa | 41 | |
| 509b8ab2 TS |
42 | PICA 61 system emulation |
| 43 | ------------------------ | |
| 44 | - No framebuffer support yet. | |
| 45 | ||
| 15dcf5aa TS |
46 | MALTA system emulation |
| 47 | ---------------------- | |
| 2c52c816 | 48 | - We fake firmware support instead of doing the real thing |
| ebbd0ffd TS |
49 | - Real firmware (YAMON) falls over when trying to init RAM, presumably |
| 50 | due to lacking system controller emulation. | |
| 0300e3fa TS |
51 | - Bonito system controller not implemented |
| 52 | - MSC1 system controller not implemented |