/[gxemul]/trunk/TODO
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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revision 6 by dpavlin, Mon Oct 8 16:18:11 2007 UTC revision 26 by dpavlin, Mon Oct 8 16:20:10 2007 UTC
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1  $Id: TODO,v 1.133 2005/05/25 06:40:16 debug Exp $  $Id: TODO,v 1.298 2006/06/25 11:08:04 debug Exp $
2    
3  Here's a short list of what I have left to do on GXemul. This file is a mess.  Hm. This file is in random order, and not all parts of it are up-to-date.
 Order is random. Don't trust it to be up-to-date.  
4    
5          Caches / memory hierarchies: (this is mostly MIPS-specific)  --------------
6                  o)  MIPS coproc.c: bits in config registers should reflect  
7                      correct cache sizes for _all_ CPU types. (currently only          x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
8                      implemented for R4000, R1x000, and a few others)          x)  Find a way to get rid of the cpu_create_or_reset_tc in the
9                  o)  src/memory*.c: Implement correct cache emulation for              R2000/R3000 cache isolation code. (NetBSD works without it,
10                      all CPU types. (currently only R2000/R3000 is implemented)              but not Ultrix and Linux yet.)
11                      (per CPU, multiple levels should be possible,          x)  Formalize the statistics gathering stuff for dyntrans...
12                      associativity etc!)          x)  ... and use it to optimize MIPS dyntrans stuff.
13                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)          x)  Clock framework? Go through all clock devices, make sure they
14                  o)  Move the -S (fill mem with random) functionality into the              return correct data, and run at correct speeds!
15                      memory.c subsystem, not machine.c or wherever it is now          x)  Optimizations, continuing on 64-bit issues etc with dyntrans
16                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)          x)  Dyntrans with SMP... lots of work to be done here.
17                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          x)  Dyntrans with cache emulation... lots of work here as well.
18                      (using manual swap-out of blocks to disk, ugly)          x)  Actually use the settings object, better debugger stuff, etc.
19                  o)  A global command line option should be used to turn          x)  Wait for new releases of NetBSD, and test with those.
20                      cache emulation on or off. When off, caches should be  
21                      faked like they are right now. When on, caches and  --------------
22                      memory latencies should be emulated as correctly as  
23                      possible.  SMP:
24            o)  dev_mp doesn't work well with dyntrans yet
25          Network layer:          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
26                  o)  Multiple networks per emulation, and let different  
27                      NICs in machines connect to different networks.  MIPS:
28                  o)  Network across multiple hosts.          o)  Fix invalidate_asid so it works well for non-R3000 too!
29                  o)  Fixed MAC addresses for NICs, fixed IPv4 addresses if          x)  [Re]add an interrupt-asserted bit for MIPS, to speed up
30                      DHCP or RARP is used.              interrupt handling slightly?
31                  o)  many other issues: see src/net.c          +)  Print a warning on the first reserved instruction.
32            +)  Some more work on opcodes.
33          Configure script:                  x) MIPS64 revision 2.
34                  o)  Only enable Alpha prefetch on pca56 etc, not on ev4, ev5.                  x) _MAYBE_ TX79 and R5900 actually differ in their
35                  o)  Use getopts?                     opcodes? Check this carefully!
36                  o)  X11 libs and headers via command line option?          o)  Dyntrans: Count register updates are probably not 100% correct yet.
37                  o)  Verify that the configure script, building and running          o)  Dyntrans: SMP correctness
38                      the emulator works on some platforms:          o)  Refactor code for performance and readability/maintainability.
39                          +)  Irix, AIX, QNX          o)  Instruction combinations? Possible candidates (but profile first!):
40                          +)  MacOS X  (I've not tried this personally yet)                  o)  multiple loads/stores in a row
41                          +)  Ultrix using gcc? (Inside the emulator)                  o)  strlen, memset loops etc
42                    o)  compare + branch
43          CPU emulation:          o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
44                  o)  Binary translation:              a rotation bit which differs from previous ISAs.
45                          +)  use an Intermediate Representation!          o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
46                          +)  recursive translation?              _NOT_ the same as for R5900!
47                          +)  basic blocks instead of one-instruction? :)          o)  R4000 and others:
48                          +)  on Alpha: don't assume pca56-like byte load/store?                  x)  watchhi/watchlo exceptions, and other exception
49                          +)  write backends for UltraSparc and MIPS                      handling details
50                          +)  see src/bintrans.c for more info          o)  R10000 and others:  (R12000, R14000 ?)
51                  o)  All the non-MIPS modes need a bit of work.                  x)  memory space, exceptions, ...
52                    x)  use cop0 framemask for tlb lookups
53          MIPS CPU emulation:                      (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)
54                  o)  Instructions:  
55                          o)  Regression tests (see tests/README for more info):  Dyntrans:
56                                  o)  Floating point exception handling, and          x)  Move the mips_init_64bit_dummy_tables() etc calls into
57                                          add more instructions.              src/cpu.c, for all 64-bit cpus?
58                                  o)  Finish the MIPS16 translator, and test it!          x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably
59                                  o)  MIPS ISA I, II, III, IV                  help performance a bit.
60                                  o)  MIPS V (SIMD vector stuff?)          x)  Common fatal_abort() function, which drops into the debugger
61                                  o)  MDMX  (MIPS Digital Media Extension)                  without continuing.
62                                  o)  MIPS 3D          x)  INVALIDATION should cause translations in _all_ cpus to be
63                                  o)  MIPS MT (Multi-thread stuff) (What's this?)              invalidated, e.g. on a write to a write-protected page
64                          o)  Warn about mis-used bit fields (ie bits that              (containing code)
65                              should be all zeroes, warn about if they are not)!          x)  better (formally defined) instr call statistics (-s command
66                              Both for coprocessor registers and for instruction              line option?), multiple different types? (virtual pc, physical pc)
67                              opcodes.          x)  Call/return hints?
68                          o)  the special2 stuff is a mess right now          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
69                          o)  warn and/or cause exceptions for unimplemented          x)  H8?
70                              instructions (depending on CPU type)          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
71                  o)  R2000/R3000:          x)  true recompilation backend? think carefully about this,
72                          x)  R3000 "tri-byte stores". (What's this?)              experiment in a separate project (not in GXemul)
73                  o)  R4000 and others:          x)  Remove the dyntrans_alignment_check functionality; although
74                          x)  watchhi/watchlo exceptions, and other exception              it gives slightly higher peformance sometimes, it increases
75                              handling details              the complexity of the code too much!
76                  o)  R10000 and others:  (R12000, R14000 ?)  
77                          x)  memory space, exceptions, ...  Alpha:
78                          x)  use cop0 framemask for tlb lookups          o)  Virtual memory (tlbs etc)
79                              (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)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
80                  o)  Implement load delays?  Warnings on interlocks.  
81                  o)  Implement all coprocessor 0 bits / functions.  SPARC:
82                          x)  coproc 0 selectors! (R4000 ?)          o)  Add all registers (floating point, control regs etc)
83                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird          o)  Save/restore register windows etc!
84                          TLB/cache? 128-bit GPRs, new instructions),          o)  Disassemly of some more instructions.
85                          4K (note: NOT R4000), 5K (note: NOT R5000),          o)  Are sll etc 32-bit sign-extending or zero-extending?
86                          R6000 (ISA II), R8000          o)  Finish the cmp (subcc) flag computation code.
87                  o)  Multi-cpu stuff:          o)  Finish the GDB register stuff.
88                          +)  SGI's NUMA architecture. Study  
89                                  x)  Linux sources  Debugger:
90                                  x)  SGI's specs on NUMA address space          o)  How does SMP debugging work? Does it simply use "threads"?
91                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(                  What if the guest OS (running on an emulated SMP machine)
92                          +)  Own experiments with ycx2.                  has a usertask running, with userland threads?
93            o)  Try to make the debugger more modular and, if possible, reentrant!
94          Emulation of specific machines and devices:          o)  Remove the emul command? (But show network info if showing
95                  o)  Clean up stuff to make it possible to emulate multiple                  machines?)
96                      (different) machines simultaneously.          o)  Generalize the expression evaluator. (debugger_expr.c?)
97                  o)  Use same clock for all emulations and machines.                  settable variables      ("show nr of instructions on average")
98                  o)  Clean up the device stuff (registering of devices etc)                  emul[x]                 defaults to current emul
99                  o)  Various SCSI and IDE controllers                  machine[x]              defaults to current machine
100                  o)  PS/2-style keyboard controller (for several machines)                  cpu[x]                  defaults to currently focused cpu
101                  o)  Generic busses;                  registers               cpu arch dependent (#-prefix)
102                          x)  PCI:  i/o and interrupts                  symbols                 @-prefix
103                          x)  QBus-22 (DECsystem 5500, 5400?)                  numeric constants       decimal, hex, and octal ($-prefix)
104                  o)  DECstations (pmax):                  boolean                 yes,no, true,false
105                          x)  ioasic                  operators (+ - * / % & | ^ !)
106                          x)  framebuffers:                  parentheses for grouping subexpressions
107                                  +)  better cursor support, overlays?,                  NOTE: the change from % to # for register prefix!
108                                  +)  2D/3D acceleration, PX[G]                  examples:
109                          x)  status words / control words, make this more                                  emul[0].machine[2].cpu[0].pc
110                                  portable/cleaner                                  machine[test2].cpu[1].ra = main
111                          x)  scsi controller(s): sii, DMA for asc                                  settings.show_trace_tree = yes
112                          x)  serial controllers: ssc, scc (and more work on dc?)  
113                          x)  nvram on decstation 5000/125:  when using X11,                  Settings:
114                                  set console=g or similar                          o)  Remove a setting.
115                          x)  DECstation 5840? "xbi-based SMP"                          o)  Read/write a setting given a name. (Read as
116                  o)  SGI and ARC machines (sgimips, arc):                              string and/or int64_t simultaneously?)
117                          x)  IP32 ("O2"): (Lots of stuff)  
118                                  +)  mec (ethernet)                  Help command should have subsections! One for "expressions",
119                                  +)  pci                  mirrored in the documentation, but the internal help should
120                                  +)  ahc (scsi)                  be the one that should be considered correct.
121                                  +)  ps2 kbd          o)  see src/debugger.c for more
122                                  +)  memory controller  
123                                  +)  framebuffer/graphics  POWER/PowerPC:
124                                  +)  caches          x)  PPC optimizations; instr combs
125                          x)  more ARCBIOS stuff          x)  64-bit stuff
126                          x)  Memory/interrupt controllers          x)  find and fix the bug which causes NetBSD/macppc to fail after
127                          x)  IP30 (Linux with graphics support?)              an install!
128                          x)  SMP / NUMA?  (SGI and various ARC machines)          x)  macppc: adb controller; keyboard (for framebuffer mode)
129                  o)  Playstation 2:          x)  make OpenBSD/macppc work (PCI controller stuff)
130                          Hardware:  OHCI usb controller, keyboard, ...  
131                  o)  Cobalt:  PCI and interrupt system, ethernet,  Algor:
132                          harddisk controller(s)          PCI and ISA and LOCAL interrupts! --> wdc could start working
133                  o)  Less interesting platforms:          Add interrupt controller in dev_algor.c.
134                          o)  newsmips:  
135                                  o)  NetBSD/newsmips, get it to detect a "real"  ARM:
136                                      model, right now everything is 100% bogus          o)  try to get netbsd/evbarm 3.x running (iq80321)
137                          o)  mipsco? (NetBSD)          o)  make the xscale counter registers (ccnt) work
138                          o)  wgrisc? (big endian R3000, in OpenBSD's attic)          o)  make the ata controller usable for FreeBSD!
139                          o)  other embedded / evaluation MIPS boards          o)  zaurus for openbsd...
140                          o)  Playstation 1? R3000A. Weird hardware?          o)  debian/cats crashes because of unimplemented coproc stuff.
141                                  No FPU, but something as coproc 2.              fix this?
142                          o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp  
143                                  (R4300, 4MB RAM, really weird memory map)  Cache simulation:
144                  o)  non-MIPS          o)  Separate from the CPU concept, so that multi-core CPUs sharing
145                e.g. a L2 cache can be simulated (?)
146          File/disk handling:          o)  Instruction cache emulation is easiest (if separate from the
147                  o)  More than one type of disk in a machine (say, IDE + FLOPPY,              data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
148                      or SCSI + IDE); how to handle this nicely?              NOTE: if the architecture has a delay slot, then an instruction
149                  o)  Read function argument count and types from binaries? (ELF?)              slot can actually be executed as 2 instructions.
150                  o)  ELF: separate LE/BE (MIPS instruction format) from LSB/MSB          o)  Data cache emulation = harder; each arch's load/store routines
151                          (ELF structure format)?              must include support? running one instruction at a time and
152                  o)  Better handling of tape files              having a cpu-dependant lookup function for each instruction
153                  o)  gzip support (also for non-ISO9660 files)              is another option (easier to implement, but very very slow).
154    
155          Userland ABI emulation:  Documentation:
156                  o)  see src/useremul.c          o)  machines, cpus, devices.
157            o)  Automagic documentation generation:
158          Terminal based interactive debugger:                  x)  REMEMBER that several machines/devices can be in
159                  o)  see src/debugger.c                          the same source file!
160            o)  Try to rewrite the install instructions for those machines
161          Terminal/console stuff:              that use 3MAX into using CATS? (To remove the need to a raw
162                  o)  allow emulated serial ports to be connected to the outside              ffs partition using up all of the disk image.)
163                      world in a more generic way, or even to other emulated  
164                      machines(!)  More generic out_of_memory error reporting, and check everywhere!
165            Causes: OpenBSD has low default limits for normal users.
166          GDB interface? (Maybe not necessary; the built-in debugger feels                  Host is 32-bit? (32-bit hosts are limited to 4 GB or less
167          more useful.)                  of userspace memory.)
168                    You are actually low on RAM. (As trivial as this might sound,
169          GUI, interactive debugger?  GTK+?  (The GUI _must be optional_!)                  Unix systems usually allow processes to allocate virtual
170                  o)  Breakpoints (complex expressions? combinations of register                  memory beyond the amount of RAM in the machine.)
171                          states, memory accesses and so on)  
172                  o)  Instruction trace  Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc.
173                  o)  Disassembly of RAM (_NOT_ the same as instruction trace)          Use the debugger's symbolic name stuff. (which will have to be
174                  o)  Function call trace          extended soon to support stuff like  "2*x + symbol + y" etc. cool
175                  o)  Inspection of CPU registers/state, coprocessor          stuff)
176                          registers/state, any device registers/state/contents  
177                          o)  Framebuffers in windows / tabs.  Sprite (guest OS for DECstation emulation)
178                          o)  Contents of RAM          x)  Timing problems during bootup?
179                  o)  "Start new emulation" should allow amount of  
180                          RAM and nr of cpus to easily be specified.  The Device subsystem:
181                          Multiple simultaneous machines should be possible.          x)  allow devices to be moved and/or changed in size (down to a
182                  o)  Disk images.              minimum size, etc, or up to a max size)
183            x)  keep track of interrupts and busses? actually, allowing any device
184          Regression tests:              to be a bus might be a nice idea.
185                  o)  see tests/          x)  turn interrupt controllers into devices? :-)
186            x)  refactor various clocks/nvram/cmos into one device?
187          Save state of the whole emulated machine, to be able to load it back  
188                  in later?  (Memory, all device's states, all registers and  Clocks:
189                  so on.  Like taking a snapshot. (SimOS seems to do this,          x)  General framework for automagic clock adjustment for _all_
190                  according to its website.))              kinds of clocks and timers. (Which should be possible to turn
191                off, of course, like the way DECstation emulation works now.)
192          Better X-windows functionality:  
193                  o)  CLEAN UP the ugly event code  PCI:
194                  o)  Mouse clicks can be "missed" in the current system; this is          x)  last write was ffffffff ==> fix this, it should be used
195                      not good. They should be put on a stack of some kind.              together with a mask to get the correct bits. also, not ALL
196                  o)  More 2D and 3D framebuffer acceleration.              bits are size bits! (lowest 4 vs lowest 2?)
197                  o)  Non-resizable windows?  Or choose scaledown depending          x)  add support for address fixups
198                          on size (and center the image, with a black border).          x)  generalize the interrupt routing stuff (lines etc). this should
199                  o)  Different scaledown on different windows?              be per machine? or per bus, that's better
200                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)          x)  add a "pcn" NIC (AMD PCnet32 Lance 79c970 (PCI 1022:2000)),
201                  o)  Keyboard and mouse events:              could be useful for several machine modes (Malta, Algor, evbarm,
202                          x)  Do this for more machines than just DECstation              hp700?, macppc, etc.)
203                          x)  more X11 cursor keycodes  
204                          x)  Keys like CTRL, ALT, SHIFT do not get through  Network layer:
205                              by themselves (these are necessary for example          o)  DHCP (for Debian and BSD installers :-)
206                              to change the font of an xterm in X in the          o)  increase performance
207                              emulator)          o)  don't rely on NetBSD-ish usage
208                  o)  Generalize the framebuffer stuff by moving _ALL_ X11          o)  Multiple networks per emulation, and let different
209                          specific code to src/x11.c!              NICs in machines connect to different networks.
210            o)  many other issues: see src/net.c
211          Statistics:  (this could be interesting)  
212                  o)  Save to file and show graphics. It should be possible to  Busses:
213                      run gxemul after a simulation to just show the graphics,          o)  Redesign the entire "mainbus" concept!
214                      or convert to a .ppm or .tga or similar.          o)  Busses should be placed in a hierarchical tree!
215                  o)  memory accesses (to measure cache efficiency and          o)  Easily configurable interrupt routing in SMP systems.
216                          page coloring efficiency)          o)  Specific clock/bus speeds, cpu speeds etc.
217                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS          o)  Synchronization over network? or at least in dyntrans within
218                  o)  percentage of time spent in different "states", such as              one emulated machine
219                      running userland code, kernel code, or idling (for CPUs          o)  dev->bus: TurboChannel, PCMCIA, ADB?
220                      that have such an instruction, or whenever the PC is  
221                      inside a specific idle-function (address range)).  Config file parser:
222                      Possible additional state (for example on R3000): caches          o)  Rewrite it from scratch!
223                      disabled.          o)  Usage of any expression available through the debugger
224                  o)  position of read/write on (SCSI) disks          o)  Support for running debugger commands (like the -c
225                command line option)
226    
227    Floating point layer:
228            o)  make it common enough to be used by _all_ emulation modes
229            o)  implement more stuff
230            o)  non-IEEE modes (i.e. x86)?
231    
232    Userland emulation:
233            x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
234            x)  Dynamic linking? Hm.
235    
236    Sound:
237            x)  generic sound framework
238            x)  add one or more sound cards as devices
239    
240    ASC SCSI controller:
241            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
242                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
243                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
244                2005/11/06/0024.html suggests that.)
245    
246    Caches / memory hierarchies: (this is mostly MIPS-specific)
247            o)  MIPS coproc.c: bits in config registers should reflect
248                correct cache sizes for _all_ CPU types. (currently only
249                implemented for R4000, R1x000, and a few others)
250            o)  src/memory*.c: Implement correct cache emulation for
251                all CPU types. (currently only R2000/R3000 is implemented)
252                (per CPU, multiple levels should be possible,
253                associativity etc!)
254            o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
255            o)  Move the -S (fill mem with random) functionality into the
256                memory.c subsystem, not machine.c or wherever it is now
257            o)  ECC stuff, simulation of memory errors?  (Machine dependent)
258            o)  More than 4GB of emulated RAM, when run on a 32-bit host?
259                (using manual swap-out of blocks to disk, ugly)
260            o)  A global command line option should be used to turn
261                cache emulation on or off. When off, caches should be
262                faked like they are right now. When on, caches and
263                memory latencies should be emulated as correctly as
264                possible.
265    
266    File/disk/symbol handling:
267            o)  Better handling of tape files
268            o)  Read function argument count and types from binaries? (ELF?)
269            o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
270                Microsoft's C++, so multiple schemes must be possible. See
271                URL at top of src/symbol_demangle.c for more info.
272    
273    Userland ABI emulation:
274            o)  see src/useremul.c
275    
276    Terminal/console:
277            o)  allow emulated serial ports to be connected to the outside
278                world in a more generic way, or even to other emulated
279                machines(?)
280    
281    Save state of the whole emulated machine, to be able to load it back
282            in later?  (Memory, all device's states, all registers and
283            so on.  Like taking a snapshot. (SimOS seems to do this,
284            according to its website.))
285    
286    Better framebuffer and X-windows functionality:
287            o)  -Yx sometimes causes crashes.
288            o)  Simple device access to framebuffer_blockcopyfill() etc,
289                and text output (using the built-in fonts), for dev_fb.
290            o)  CLEAN UP the ugly event code
291            o)  Mouse clicks can be "missed" in the current system; this is
292                not good. They should be put on a stack of some kind.
293            o)  More 2D and 3D framebuffer acceleration.
294            o)  Non-resizable windows?  Or choose scaledown depending
295                    on size (and center the image, with a black border).
296            o)  Different scaledown on different windows?
297            o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
298            o)  Bug reported by Elijah Rutschman on MacOS with weird
299                keys (F5 = cursor down?).
300            o)  Keyboard and mouse events:
301                    x)  Do this for more machines than just DECstation
302                    x)  more X11 cursor keycodes
303                    x)  Keys like CTRL, ALT, SHIFT do not get through
304                        by themselves (these are necessary for example
305                        to change the font of an xterm in X in the
306                        emulator)
307            o)  Generalize the framebuffer stuff by moving _ALL_ X11
308                    specific code to src/x11.c!
309    
310    Statistics:  (this could be interesting)
311            o)  Save to file and show graphics. It should be possible to
312                run gxemul after a simulation to just show the graphics,
313                or convert to a .ppm or .tga or similar.
314            o)  memory accesses (to measure cache efficiency and
315                    page coloring efficiency)
316            o)  nr of simultaneous ASIDs in use in the TLB, for MIPS
317            o)  percentage of time spent in different "states", such as
318                running userland code, kernel code, or idling (for CPUs
319                that have such an instruction, or whenever the PC is
320                inside a specific idle-function (address range)).
321                Possible additional state (for example on R3000): caches
322                disabled.
323            o)  position of read/write on (SCSI) disks
324    

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