--- trunk/TODO 2007/10/08 16:19:23 20 +++ trunk/TODO 2007/10/08 16:20:40 30 @@ -1,155 +1,408 @@ -$Id: TODO,v 1.176 2005/11/13 00:14:05 debug Exp $ +$Id: TODO,v 1.343 2006/08/14 18:46:30 debug Exp $ -NOTE: This TODO is hopefully out-of-date. I don't keep it updated. +Hm. This file is in random order, and not all parts of it are up-to-date. -=============================================================================== -Old MIPS bintrans: - x) call/return address cache? - x) Turn the MIPS cpu family stuff into dyntrans. +Implementation: + x) ARM "wait"-like instruction. + x) CLOCK FRAMEWORK! + x) Mouse support for NetBSD/pmax 4.x! + x) See netwinder_reset() in NetBSD; the current "an internal error + occured" message after reboot/halt is too ugly. + x) 64-bit ranges in src/cpus/memory_mips_v2p.c + x) Revert the dyntrans page template experiment? Hm. + x) Refactor the cpu type detection/initialization/listing. + Macro, which can be used as long as the cpu definitions + contain a 'name'? + x) Testmachine includes: + + dev_fb block fill and copy + + dev_fb draw characters (from the built-in font)? + + dev_fb input device? mouse pointer coordinates and buttons + (allow changes in these to cause interrupts as well?) + + Redefine the halt() function so that it stops "sometimes + soon", i.e. usage in demo code should be: + for (;;) { + halt(); + } + x) Continue on SPARC emulation + + Enable it in the configure script as soon as it can + run all the demo programs. + x) Continue on Alpha emulation (virtual memory, etc). Cleanup. + x) Nicer MIPS status bits in register dumps. + x) Alignment exceptions (MIPS, PPC, ARM?, ...) + x) Rewrite the networking stack; make OpenBSD work better as a guest + OS, fix the performance problems, make Linux work with DHCP, etc. + Support VDE (vde.sf.net)? Allow SLIP connections, possibly PPP, + in addition to ethernet? + x) Implement more ethernet NICs. + x) IOP (I2O) device? + +Documentation: + x) "Install netbsd/pmax first" => only use the install kernel? + x) Rewrite the section about experimental devices, after the + framebuffer acceleration has been implemented, and demos + written. (Symbolic names instead of numbers; example + use cases, etc. Mention demo files that use the various + features?) + x) "a very simple linear framebuffer device (for graphics output)" + under "which machines does gxemul emulate" ==> better + description? + x) Better description on how to set up a cross compiler? + Example for MIPS64. + +Long-term design: + x) Instruction combination collisions? How to avoid easily... + x) Think about how to do both SHmedia and SHcompact in a reasonable + way! + o) Actually use the settings object, better debugger stuff, etc! + o) Debugger command for enabling/disabling instruction statistics + during runtime. machine.statistics = on|off + x) MAINBUS REDESIGN! + x) PCI redesign... I need to read up on how PCI actually works :) + x) Clock framework! Go through all clock devices, make sure they + return correct data, and run at correct speeds! + x) Dyntrans with valgrind-inspired memory checker. (In memory_rw, + it would be reasonably simple to add; in each individual fast + load/store routine = a lot more work, and it would become + kludgy very fast.) + x) Dyntrans with SMP... lots of work to be done here. + x) Dyntrans with cache emulation... lots of work here as well. + x) Reimplement the config file parser from scratch. + +------------------------------------------------------------------------------- + +Simple Valgrind-like checks? + o) Mark every address with bits which tell whether or not the address + has been written to. + o) What should happen when programs are loaded? Text/data, bss (zero + filled). But stack space and heap is uninitialized. + o) Uninitialized local variables: + A load from a place on the stack which has not previously + been stored to => warning. Increasing the stack pointer using + any available means should reset the memory to uninitialized. + o) If calls to malloc() and free() can be intercepted: + o) Access to a memory area after free() => warning. + o) Memory returned by malloc() is marked as not-initialized. + o) Non-passive, but good to have: Change the argument + given to malloc, to return a slightly larger memory + area, i.e. margin_before + size + margin_after, + and return the pointer + margin_before. + Any access to the margin_before or _after space results + in warnings. (free() must be modified to free the + actually allocated address.) + +SMP: + o) dev_mp doesn't work well with dyntrans yet + o) In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans + +MIPS: + +) Some more work on opcodes. + x) The "wait" instruction. How to implement this functionality? + (SMP, non-MIPS, interrupt correctness, host idling, ...) + x) MIPS64 revision 2. + o) Find out which actual CPUs implement the rev2 ISA! + x) _MAYBE_ TX79 and R5900 actually differ in their + opcodes? Check this carefully! + o) Dyntrans: Count register updates are probably not 100% correct yet. + o) Refactor code for performance and readability/maintainability. + o) DROTR32 and similar MIPS64 rev 2 instructions, which have + a rotation bit which differs from previous ISAs. + o) EI and DI instructions for MIPS64/32 rev 2. NOTE: These are + _NOT_ the same as for R5900! + o) (Re)implement 128-bit loads/stores for R5900. + o) R4000 and others: + x) watchhi/watchlo exceptions, and other exception + handling details + o) R10000 and others: (R12000, R14000 ?) + x) memory space, exceptions, ... + x) use cop0 framemask for tlb lookups + (http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/hdwr/bks/SGI_Developer/books/R10K_UM/sgi_html/t5.Ver.2.0.book_284.html) Dyntrans: - x) Separate data and instruction translations? - x) Generalize the inline quick_pc_to_pointers? - x) Call/return hints... - x) More 64-bit stuff. + x) Redesign/rethink the delay slot mechanism used for e.g. MIPS, + so that it caches a translation (that is, an instruction + word and the instr_call it was translated to the last + time), so that it doesn't need to do slow + to_be_translated for each end of page? + x) Program Counter statistics: + Per machine? What about SMP? All data to the same file? + A debugger command should be possible to use to enable/ + disable statistics gathering. + Configuration file option! + x) Common fatal_abort() function, which drops into the debugger + without continuing. + x) INVALIDATION should cause translations in _all_ cpus to be + invalidated, e.g. on a write to a write-protected page + (containing code) + x) 16-bit encodings? (MIPS16, ARM Thumb, SH3, ...) x) Lots of other stuff: see src/cpus/README_DYNTRANS + x) true recompilation backend? think carefully about this, + experiment in a separate project (not in GXemul) + o) First test would be to just implement a simple + instruction such as MIPS' addiu or lui, on AMD64 + hosts... + x) Idle loop detection? (Depends on target.) Could be turned + into usleep(1) or similar on the host... except when doing + e.g. SMP emulation. Then it becomes trickier. + +Transputer: + x) Implement support for Helios binaries. + x) Stack and register contents at startup? + x) Figure out how to boot an entire Helios distribution. + x) Implement all instructions. :) + +Alpha: + o) Virtual memory (tlbs etc) + o) Get {NetBSD,OpenBSD,Linux}/alpha booting. :) + +SPARC: + o) Load/stores to alternate address spaces! + o) Save/restore register windows etc! + o) Finish the subcc and addcc flag computation code. + o) Add more registers (floating point, control regs etc) + o) Disassemly of some more instructions? + o) Are sll etc 32-bit sign-extending or zero-extending? + o) Finish the GDB register stuff. + o) SPARC v8, v7 etc? + +Debugger: + o) How does SMP debugging work? Does it simply use "threads"? + What if the guest OS (running on an emulated SMP machine) + has a usertask running, with userland threads? + o) Try to make the debugger more modular and, if possible, reentrant! + o) Remove the emul command? (But show network info if showing + machines?) + o) Generalize the expression evaluator. (debugger_expr.c?) + settable variables ("show nr of instructions on average") + emul[x] defaults to current emul + machine[x] defaults to current machine + cpu[x] defaults to currently focused cpu + registers cpu arch dependent (#-prefix) + symbols @-prefix + numeric constants decimal, hex, and octal ($-prefix) + boolean yes,no, true,false + operators (+ - * / % & | ^ !) + parentheses for grouping subexpressions + NOTE: the change from % to # for register prefix! + examples: + emul[0].machine[2].cpu[0].pc + machine[test2].cpu[1].ra = main + settings.show_trace_tree = yes + + Settings: + o) Remove a setting. + o) Read/write a setting given a name. (Read as + string and/or int64_t simultaneously?) + o) Warnings when exiting the emulator, if the + settings have not been removed exactly in + the same way as they were added? This would + improve code cleanliness in the long term. + (I.e. require a corresponding _destroy() + function for all _new functions... machine_ + cpu_ etc.) + + Help command should have subsections! One for "expressions", + mirrored in the documentation, but the internal help should + be the one that should be considered correct. + o) see src/debugger.c for more + +POWER/PowerPC: + x) PPC optimizations; instr combs + x) 64-bit stuff: either Linux on G5, or perhaps some hobbyist + version of AIX? (if there exists such a thing) + x) find and fix the bug which causes NetBSD/macppc to fail after + an install! + x) macppc: adb controller; keyboard (for framebuffer mode) + x) make OpenBSD/macppc work (PCI controller stuff) + +Algor: + PCI interrupts... needed or stuff like the tlp NIC? + +ARM: + o) try to get netbsd/evbarm 3.x running (iq80321) + o) make the xscale counter registers (ccnt) work + o) make the ata controller usable for FreeBSD! + o) zaurus for openbsd... + o) debian/cats crashes because of unimplemented coproc stuff. + fix this? + +Cache simulation: + o) Command line flags for: + o) CPU endianness? + o) Cache sizes? (multiple levels) + o) Separate from the CPU concept, so that multi-core CPUs sharing + e.g. a L2 cache can be simulated (?) + o) Instruction cache emulation is easiest (if separate from the + data cache); similar hack as the S;I; hack in cpu_dyntrans.c. + NOTE: if the architecture has a delay slot, then an instruction + slot can actually be executed as 2 instructions. + o) Data cache emulation = harder; each arch's load/store routines + must include support? running one instruction at a time and + having a cpu-dependant lookup function for each instruction + is another option (easier to implement, but very very slow). + +Documentation: + o) machines, cpus, devices. + o) Automagic documentation generation: + x) REMEMBER that several machines/devices can be in + the same source file! + o) Try to rewrite the install instructions for those machines + that use 3MAX into using CATS? (To remove the need to a raw + ffs partition using up all of the disk image.) + +More generic out_of_memory error reporting, and check everywhere! + Causes: OpenBSD has low default limits for normal users. + Host is 32-bit? (32-bit hosts are limited to 4 GB or less + of userspace memory.) + You are actually low on RAM. (As trivial as this might sound, + Unix systems usually allow processes to allocate virtual + memory beyond the amount of RAM in the machine.) + +Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc. + Use the debugger's symbolic name stuff. (which will have to be + extended soon to support stuff like "2*x + symbol + y" etc. cool + stuff) + +The Device subsystem: + x) allow devices to be moved and/or changed in size (down to a + minimum size, etc, or up to a max size) + x) keep track of interrupts and busses? actually, allowing any device + to be a bus might be a nice idea. + x) turn interrupt controllers into devices? :-) + x) refactor various clocks/nvram/cmos into one device? + +Clocks: + x) General framework for automagic clock adjustment for _all_ + kinds of clocks and timers. (Which should be possible to turn + off, of course, like the way DECstation emulation works now.) + +PCI: + x) last write was ffffffff ==> fix this, it should be used + together with a mask to get the correct bits. also, not ALL + bits are size bits! (lowest 4 vs lowest 2?) + x) add support for address fixups + x) generalize the interrupt routing stuff (lines etc). this should + be per machine? or per bus, that's better + x) add a "pcn" NIC (AMD PCnet32 Lance 79c970 (PCI 1022:2000)), + could be useful for several machine modes (Malta, Algor, evbarm, + hp700?, macppc, etc.) + +Network layer: + o) DHCP (for Debian and BSD installers :-) + o) increase performance + o) don't rely on NetBSD-ish usage + o) Multiple networks per emulation, and let different + NICs in machines connect to different networks. + o) many other issues: see src/net.c + +Busses: + o) Redesign the entire "mainbus" concept! + o) Busses should be placed in a hierarchical tree! + o) Easily configurable interrupt routing in SMP systems. + o) Specific clock/bus speeds, cpu speeds etc. + o) Synchronization over network? or at least in dyntrans within + one emulated machine + o) dev->bus: TurboChannel, PCMCIA, ADB? + +Config file parser: + o) Rewrite it from scratch! + o) Usage of any expression available through the debugger + o) Support for running debugger commands (like the -c + command line option) + +Floating point layer: + o) make it common enough to be used by _all_ emulation modes + o) implement more stuff + o) non-IEEE modes (i.e. x86)? Userland emulation: - x) Lots of stuff. + x) Lots of stuff; freebsd and netbsd (and linux?) syscalls. x) Dynamic linking? Hm. -Misc: - Redesign the entire "mainbus" concept: - o) Easily configurable interrupt routing in SMP systems. - o) Specific clock/bus speeds, cpu speeds etc. - o) Synchronization over network? - - Caches / memory hierarchies: (this is mostly MIPS-specific) - o) MIPS coproc.c: bits in config registers should reflect - correct cache sizes for _all_ CPU types. (currently only - implemented for R4000, R1x000, and a few others) - o) src/memory*.c: Implement correct cache emulation for - all CPU types. (currently only R2000/R3000 is implemented) - (per CPU, multiple levels should be possible, - associativity etc!) - o) R2000/R3000 isn't _100%_ correct, just almost correct :) - o) Move the -S (fill mem with random) functionality into the - memory.c subsystem, not machine.c or wherever it is now - o) ECC stuff, simulation of memory errors? (Machine dependant) - o) More than 4GB of emulated RAM, when run on a 32-bit host? - (using manual swap-out of blocks to disk, ugly) - o) A global command line option should be used to turn - cache emulation on or off. When off, caches should be - faked like they are right now. When on, caches and - memory latencies should be emulated as correctly as - possible. - - Network layer: - o) Multiple networks per emulation, and let different - NICs in machines connect to different networks. - o) many other issues: see src/net.c - - MIPS CPU emulation: - o) i386 bintrans backend: movn etc, slt[u] for - 64-bit mode, 64-bit shifts etc - o) Instructions: - o) All ISAs: - o) Floating point exception handling, and - add more instructions. - o) Finish the MIPS16 translator, and test it! - o) MIPS ISA I, II, III, IV - o) MIPS V (SIMD vector stuff?) - o) MDMX (MIPS Digital Media Extension) - o) MIPS 3D - o) MIPS MT (Multi-thread stuff) (What's this?) - o) Warn about mis-used bit fields (ie bits that - should be all zeroes, warn about if they are not)! - Both for coprocessor registers and for instruction - opcodes. - o) the special2 stuff is a mess right now - o) warn and/or cause exceptions for unimplemented - instructions (depending on CPU type) - o) R2000/R3000: - x) R3000 "tri-byte stores". (What's this?) - o) R4000 and others: - x) watchhi/watchlo exceptions, and other exception - handling details - o) R10000 and others: (R12000, R14000 ?) - x) memory space, exceptions, ... - x) use cop0 framemask for tlb lookups - (http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/hdwr/bks/SGI_Developer/books/R10K_UM/sgi_html/t5.Ver.2.0.book_284.html) - o) Implement load delays? Warnings on interlocks. - o) Implement all coprocessor 0 bits / functions. - x) coproc 0 selectors! (R4000 ?) - o) R4300 (nintendo64, no mmu?), R5900 (playstation2, weird - TLB/cache? 128-bit GPRs, new instructions), - 4K (note: NOT R4000), 5K (note: NOT R5000), - R6000 (ISA II), R8000 - o) Multi-cpu stuff: - +) Interrupt routing (ie devices vs mainbus, or - connect each device to a fixed cpu) - +) SGI's NUMA architecture. Study - x) Linux sources - x) SGI's specs on NUMA address space - +) Ultrix? NetBSD doesn't do SMP on MIPS yet :-( - +) Own experiments with ycx2. - - File/disk handling: - o) Better handling of tape files - - Debugger: - o) Read function argument count and types from binaries? (ELF?) - o) Demangle C++ names. - o) see src/debugger.c for more stuff - - Userland ABI emulation: - o) see src/useremul.c - - Terminal/console stuff: - o) allow emulated serial ports to be connected to the outside - world in a more generic way, or even to other emulated - machines(!) - - Regression tests. (Needs to be totally rewritten, the old framework - was removed because it was useless.) - - Save state of the whole emulated machine, to be able to load it back - in later? (Memory, all device's states, all registers and - so on. Like taking a snapshot. (SimOS seems to do this, - according to its website.)) - - Better X-windows functionality: - o) CLEAN UP the ugly event code - o) Mouse clicks can be "missed" in the current system; this is - not good. They should be put on a stack of some kind. - o) More 2D and 3D framebuffer acceleration. - o) Non-resizable windows? Or choose scaledown depending - on size (and center the image, with a black border). - o) Different scaledown on different windows? - o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus) - o) Keyboard and mouse events: - x) Do this for more machines than just DECstation - x) more X11 cursor keycodes - x) Keys like CTRL, ALT, SHIFT do not get through - by themselves (these are necessary for example - to change the font of an xterm in X in the - emulator) - o) Generalize the framebuffer stuff by moving _ALL_ X11 - specific code to src/x11.c! - - Statistics: (this could be interesting) - o) Save to file and show graphics. It should be possible to - run gxemul after a simulation to just show the graphics, - or convert to a .ppm or .tga or similar. - o) memory accesses (to measure cache efficiency and - page coloring efficiency) - o) nr of simultaneous ASIDs in use in the TLB, for MIPS - o) percentage of time spent in different "states", such as - running userland code, kernel code, or idling (for CPUs - that have such an instruction, or whenever the PC is - inside a specific idle-function (address range)). - Possible additional state (for example on R3000): caches - disabled. - o) position of read/write on (SCSI) disks +Sound: + x) generic sound framework + x) add one or more sound cards as devices + +ASC SCSI controller: + x) NetBSD/arc 2.0 uses the ASC controller in a way which GXemul + cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem + in NetBSD itself, http://mail-index.netbsd.org/source-changes/ + 2005/11/06/0024.html suggests that.) + +Caches / memory hierarchies: (this is mostly MIPS-specific) + o) src/memory*.c: Implement correct cache emulation for + all CPU types. (currently only R2000/R3000 is implemented) + (per CPU, multiple levels should be possible, associativity etc!) + o) R2000/R3000 isn't _100%_ correct, just almost correct :) + o) Move the -S (fill mem with random) functionality into the + memory.c subsystem, not machine.c or wherever it is now + o) ECC stuff, simulation of memory errors? (Machine dependent) + o) More than 4GB of emulated RAM, when run on a 32-bit host? + (using manual swap-out of blocks to disk, ugly) + o) A global command line option should be used to turn + cache emulation on or off. When off, caches should be + faked like they are right now. When on, caches and + memory latencies should be emulated as correctly as + possible. + +File/disk/symbol handling: + o) Remove some of the complexity in file format guessing, for + Ultrix kernels that are actually disk images? + o) Better handling of tape files + o) Read function argument count and types from binaries? (ELF?) + o) Better demangling of C++ names. Note: GNU's C++ differs from e.g. + Microsoft's C++, so multiple schemes must be possible. See + URL at top of src/symbol_demangle.c for more info. + +Userland ABI emulation: + o) see src/useremul.c + +Terminal/console: + o) allow emulated serial ports to be connected to the outside + world in a more generic way, or even to other emulated + machines(?) + +Save state of the whole emulated machine, to be able to load it back + in later? (Memory, all device's states, all registers and + so on. Like taking a snapshot. (SimOS seems to do this, + according to its website.)) + +Better framebuffer and X-windows functionality: + o) -Yx sometimes causes crashes. + o) Simple device access to framebuffer_blockcopyfill() etc, + and text output (using the built-in fonts), for dev_fb. + o) CLEAN UP the ugly event code + o) Mouse clicks can be "missed" in the current system; this is + not good. They should be put on a stack of some kind. + o) More 2D and 3D framebuffer acceleration. + o) Non-resizable windows? Or choose scaledown depending + on size (and center the image, with a black border). + o) Different scaledown on different windows? + o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus) + o) Bug reported by Elijah Rutschman on MacOS with weird + keys (F5 = cursor down?). + o) Keyboard and mouse events: + x) Do this for more machines than just DECstation + x) more X11 cursor keycodes + x) Keys like CTRL, ALT, SHIFT do not get through + by themselves (these are necessary for example + to change the font of an xterm in X in the + emulator) + o) Generalize the framebuffer stuff by moving _ALL_ X11 + specific code to src/x11.c! + +Statistics: (this could be interesting) + o) Save to file and show graphics. It should be possible to + run gxemul after a simulation to just show the graphics, + or convert to a .ppm or .tga or similar. + o) memory accesses (to measure cache efficiency and + page coloring efficiency) + o) nr of simultaneous ASIDs in use in the TLB, for MIPS + o) percentage of time spent in different "states", such as + running userland code, kernel code, or idling (for CPUs + that have such an instruction, or whenever the PC is + inside a specific idle-function (address range)). + Possible additional state (for example on R3000): caches + disabled. + o) position of read/write on (SCSI) disks