/[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 12 by dpavlin, Mon Oct 8 16:18:38 2007 UTC revision 24 by dpavlin, Mon Oct 8 16:19:56 2007 UTC
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1  $Id: TODO,v 1.166 2005/08/16 05:44:33 debug Exp $  $Id: TODO,v 1.292 2006/06/23 09:13:34 debug Exp $
2    
3  ===============================================================================  Hm. This file is in random order, and not all parts of it are up-to-date.
4    
5  High priority stuff:  --------------
6    
7    Possible release schedule:
8    
9  MIPS bintrans:  0.4.0:
10          x)  call/return address cache?          x)  Quick release, even though performance for non-R3000 MIPS dyntrans
11                is really poor. (Assuming everything mentioned in the documentation
12  dyntrans:              works as expected.)
13          x)  memory write protection for ARM, but NOT for Alpha (because  
14                  it has the IMB instruction... hm)  0.4.1:
15            x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
16          x)  call/return address cache          x)  Fix the interrupt problems with Ultrix!
17            x)  Find/fix bug which is triggered when building the emulator inside
18          x)  instr_call sequence analysis support? (Useful for              NetBSD/pmax 3.0 inside the emulator!
19                  handtuning combinations.)  
20    0.4.2 ...?
21          x)  opcode statistics support?          x)  Clean-up!
22                  TODO: is instr_call statistics enough?          x)  Clock framework? Go through all clock devices, make sure they
23                return correct data, and run at correct speeds!
24          x)  support for archs that allow transparent unaligned load/stores          x)  Optimizations, continuing on 64-bit issues etc with dyntrans
25            x)  Dyntrans with SMP... lots of work to be done here.
26          x)  SMP: detect when an instruction such as ll/sc or cas is used,          x)  Dyntrans with cache emulation... lots of work here as well.
27              and "synchronize" approximately the number of executed instructions          x)  Actually use the settings object, better debugger stuff, etc.
28              (or cycles) across all CPUs.          x)  Wait for new releases of NetBSD, and test with those.
29    
30          x)  support for variable-length instructions (x86, m68k, ...)  --------------
31                  Perhaps:  don't increase the next_ic between every  
32                  instruction, but let each instruction's handler do  SMP:
33                  that for itself.          o)  dev_mp doesn't work well with dyntrans yet
34                  Problem: what about instructions crossing a (virtual)          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
35                          page boundary? They cannot be translated once  
36                          and for all :( and must be interpreted slowly!  MIPS:
37            o)  Fix invalidate_asid so it works well for non-R3000 too!
38          x)  support for THUMB or MIPS16  (arm, mips)          x)  [Re]add an interrupt-asserted bit for MIPS, to speed up
39                interrupt handling slightly?
40          x)  support for Delay slots!  (mips, sparc, hppa)          +)  Print a warning on the first reserved instruction.
41            +)  Some more work on opcodes.
42          x)  Alpha: hahaha, zapnot and inserts/extracts don't                  x) MIPS64 revision 2.
43              compile into very nice code :-|  fix this                  x) _MAYBE_ TX79 and R5900 actually differ in their
44                       opcodes? Check this carefully!
45          x)  64-bit virtual memory translation tables (PPC, etc)          o)  Dyntrans: Count register updates are probably not 100% correct yet.
46            o)  Dyntrans: SMP correctness
47          x)  x86: convert to dyntrans. LOTS of stuff to consider.          o)  Refactor code for performance and readability/maintainability.
48            o)  Instruction combinations? Possible candidates (but profile first!):
49                    o)  multiple loads/stores in a row
50  ===============================================================================                  o)  strlen, memset loops etc
51                    o)  compare + branch
52  Lower priority, but still important:          o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
53                a rotation bit which differs from previous ISAs.
54          Redesign the entire "mainbus" concept:          o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
55                  o)  Easily configurable interrupt routing in SMP systems.              _NOT_ the same as for R5900!
56                  o)  Specific clock/bus speeds, cpu speeds etc.          o)  R4000 and others:
57                  o)  Synchronization over network?                  x)  watchhi/watchlo exceptions, and other exception
58                        handling details
59          Caches / memory hierarchies: (this is mostly MIPS-specific)          o)  R10000 and others:  (R12000, R14000 ?)
60                  o)  MIPS coproc.c: bits in config registers should reflect                  x)  memory space, exceptions, ...
61                      correct cache sizes for _all_ CPU types. (currently only                  x)  use cop0 framemask for tlb lookups
62                      implemented for R4000, R1x000, and a few others)                      (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)
63                  o)  src/memory*.c: Implement correct cache emulation for  
64                      all CPU types. (currently only R2000/R3000 is implemented)  Dyntrans:
65                      (per CPU, multiple levels should be possible,          x)  Move the mips_init_64bit_dummy_tables() etc calls into
66                      associativity etc!)              src/cpu.c, for all 64-bit cpus?
67                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)          x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably
68                  o)  Move the -S (fill mem with random) functionality into the                  help performance a bit.
69                      memory.c subsystem, not machine.c or wherever it is now          x)  Common fatal_abort() function, which drops into the debugger
70                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)                  without continuing.
71                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          x)  INVALIDATION should cause translations in _all_ cpus to be
72                      (using manual swap-out of blocks to disk, ugly)              invalidated, e.g. on a write to a write-protected page
73                  o)  A global command line option should be used to turn              (containing code)
74                      cache emulation on or off. When off, caches should be          x)  better (formally defined) instr call statistics (-s command
75                      faked like they are right now. When on, caches and              line option?), multiple different types? (virtual pc, physical pc)
76                      memory latencies should be emulated as correctly as          x)  Call/return hints?
77                      possible.          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
78            x)  H8?
79          Network layer:          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
80                  o)  Multiple networks per emulation, and let different          x)  true recompilation backend? think carefully about this,
81                      NICs in machines connect to different networks.              experiment in a separate project (not in GXemul)
82                  o)  many other issues: see src/net.c          x)  Remove the dyntrans_alignment_check functionality; although
83                it gives slightly higher peformance sometimes, it increases
84          MIPS CPU emulation:              the complexity of the code too much!
85                  o)  i386 bintrans backend: movn etc, slt[u] for  
86                          64-bit mode, 64-bit shifts etc  Alpha:
87                  o)  Instructions:          o)  Virtual memory (tlbs etc)
88                          o)  All ISAs:          o)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
89                                  o)  Floating point exception handling, and  
90                                          add more instructions.  SPARC:
91                                  o)  Finish the MIPS16 translator, and test it!          o)  Add all registers (floating point, control regs etc)
92                                  o)  MIPS ISA I, II, III, IV          o)  Save/restore register windows etc!
93                                  o)  MIPS V (SIMD vector stuff?)          o)  Disassemly of some more instructions.
94                                  o)  MDMX  (MIPS Digital Media Extension)          o)  Are sll etc 32-bit sign-extending or zero-extending?
95                                  o)  MIPS 3D          o)  Finish the cmp (subcc) flag computation code.
96                                  o)  MIPS MT (Multi-thread stuff) (What's this?)          o)  Finish the GDB register stuff.
97                          o)  Warn about mis-used bit fields (ie bits that  
98                              should be all zeroes, warn about if they are not)!  Debugger:
99                              Both for coprocessor registers and for instruction          o)  How does SMP debugging work? Does it simply use "threads"?
100                              opcodes.                  What if the guest OS (running on an emulated SMP machine)
101                          o)  the special2 stuff is a mess right now                  has a usertask running, with userland threads?
102                          o)  warn and/or cause exceptions for unimplemented          o)  Try to make the debugger more modular and, if possible, reentrant!
103                              instructions (depending on CPU type)          o)  Remove the emul command? (But show network info if showing
104                  o)  R2000/R3000:                  machines?)
105                          x)  R3000 "tri-byte stores". (What's this?)          o)  Generalize the expression evaluator. (debugger_expr.c?)
106                  o)  R4000 and others:                  settable variables      ("show nr of instructions on average")
107                          x)  watchhi/watchlo exceptions, and other exception                  emul[x]                 defaults to current emul
108                              handling details                  machine[x]              defaults to current machine
109                  o)  R10000 and others:  (R12000, R14000 ?)                  cpu[x]                  defaults to currently focused cpu
110                          x)  memory space, exceptions, ...                  registers               cpu arch dependent (#-prefix)
111                          x)  use cop0 framemask for tlb lookups                  symbols                 @-prefix
112                              (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)                  numeric constants       decimal, hex, and octal ($-prefix)
113                  o)  Implement load delays?  Warnings on interlocks.                  boolean                 yes,no, true,false
114                  o)  Implement all coprocessor 0 bits / functions.                  operators (+ - * / % & | ^ !)
115                          x)  coproc 0 selectors! (R4000 ?)                  parentheses for grouping subexpressions
116                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird                  NOTE: the change from % to # for register prefix!
117                          TLB/cache? 128-bit GPRs, new instructions),                  examples:
118                          4K (note: NOT R4000), 5K (note: NOT R5000),                                  emul[0].machine[2].cpu[0].pc
119                          R6000 (ISA II), R8000                                  machine[test2].cpu[1].ra = main
120                  o)  Multi-cpu stuff:                                  settings.show_trace_tree = yes
121                          +)  Interrupt routing (ie devices vs mainbus, or  
122                              connect each device to a fixed cpu)                  Settings:
123                          +)  SGI's NUMA architecture. Study                          o)  Remove a setting.
124                                  x)  Linux sources                          o)  Read/write a setting given a name. (Read as
125                                  x)  SGI's specs on NUMA address space                              string and/or int64_t simultaneously?)
126                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(  
127                          +)  Own experiments with ycx2.                  Help command should have subsections! One for "expressions",
128                    mirrored in the documentation, but the internal help should
129          File/disk handling:                  be the one that should be considered correct.
130                  o)  Better handling of tape files          o)  see src/debugger.c for more
131    
132          Debugger:  POWER/PowerPC:
133                  o)  Read function argument count and types from binaries? (ELF?)          x)  PPC optimizations; instr combs
134                  o)  Demangle C++ names.          x)  64-bit stuff
135            x)  find and fix the bug which causes NetBSD/macppc to fail after
136          Userland ABI emulation:              an install!
137                  o)  see src/useremul.c          x)  macppc: adb controller; keyboard (for framebuffer mode)
138            x)  make OpenBSD/macppc work (PCI controller stuff)
139          Terminal based interactive debugger:  
140                  o)  see src/debugger.c  Algor:
141            PCI and ISA and LOCAL interrupts! --> wdc could start working
142          Terminal/console stuff:          Add interrupt controller in dev_algor.c.
143                  o)  allow emulated serial ports to be connected to the outside  
144                      world in a more generic way, or even to other emulated  ARM:
145                      machines(!)          o)  try to get netbsd/evbarm 3.x running (iq80321)
146            o)  make the xscale counter registers (ccnt) work
147          Regression tests.  (Needs to be totally rewritten, the old framework          o)  make the ata controller usable for FreeBSD!
148                  was removed because it was useless.)          o)  zaurus for openbsd...
149            o)  debian/cats crashes because of unimplemented coproc stuff.
150          Save state of the whole emulated machine, to be able to load it back              fix this?
151                  in later?  (Memory, all device's states, all registers and  
152                  so on.  Like taking a snapshot. (SimOS seems to do this,  Cache simulation:
153                  according to its website.))          o)  Separate from the CPU concept, so that multi-core CPUs sharing
154                e.g. a L2 cache can be simulated (?)
155          Better X-windows functionality:          o)  Instruction cache emulation is easiest (if separate from the
156                  o)  CLEAN UP the ugly event code              data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
157                  o)  Mouse clicks can be "missed" in the current system; this is              NOTE: if the architecture has a delay slot, then an instruction
158                      not good. They should be put on a stack of some kind.              slot can actually be executed as 2 instructions.
159                  o)  More 2D and 3D framebuffer acceleration.          o)  Data cache emulation = harder; each arch's load/store routines
160                  o)  Non-resizable windows?  Or choose scaledown depending              must include support? running one instruction at a time and
161                          on size (and center the image, with a black border).              having a cpu-dependant lookup function for each instruction
162                  o)  Different scaledown on different windows?              is another option (easier to implement, but very very slow).
163                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)  
164                  o)  Keyboard and mouse events:  Documentation:
165                          x)  Do this for more machines than just DECstation          o)  machines, cpus, devices.
166                          x)  more X11 cursor keycodes          o)  Automagic documentation generation:
167                          x)  Keys like CTRL, ALT, SHIFT do not get through                  x)  REMEMBER that several machines/devices can be in
168                              by themselves (these are necessary for example                          the same source file!
169                              to change the font of an xterm in X in the          o)  Try to rewrite the install instructions for those machines
170                              emulator)              that use 3MAX into using CATS? (To remove the need to a raw
171                  o)  Generalize the framebuffer stuff by moving _ALL_ X11              ffs partition using up all of the disk image.)
172                          specific code to src/x11.c!  
173    More generic out_of_memory error reporting, and check everywhere!
174          Statistics:  (this could be interesting)          Causes: OpenBSD has low default limits for normal users.
175                  o)  Save to file and show graphics. It should be possible to                  Host is 32-bit? (32-bit hosts are limited to 4 GB or less
176                      run gxemul after a simulation to just show the graphics,                  of userspace memory.)
177                      or convert to a .ppm or .tga or similar.                  You are actually low on RAM. (As trivial as this might sound,
178                  o)  memory accesses (to measure cache efficiency and                  Unix systems usually allow processes to allocate virtual
179                          page coloring efficiency)                  memory beyond the amount of RAM in the machine.)
180                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS  
181                  o)  percentage of time spent in different "states", such as  Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc.
182                      running userland code, kernel code, or idling (for CPUs          Use the debugger's symbolic name stuff. (which will have to be
183                      that have such an instruction, or whenever the PC is          extended soon to support stuff like  "2*x + symbol + y" etc. cool
184                      inside a specific idle-function (address range)).          stuff)
185                      Possible additional state (for example on R3000): caches  
186                      disabled.  Sprite (guest OS for DECstation emulation)
187                  o)  position of read/write on (SCSI) disks          x)  Timing problems during bootup?
188    
189    The Device subsystem:
190            x)  allow devices to be moved and/or changed in size (down to a
191                minimum size, etc, or up to a max size)
192            x)  keep track of interrupts and busses? actually, allowing any device
193                to be a bus might be a nice idea.
194            x)  turn interrupt controllers into devices? :-)
195            x)  refactor various clocks/nvram/cmos into one device?
196    
197    Clocks:
198            x)  General framework for automagic clock adjustment for _all_
199                kinds of clocks and timers. (Which should be possible to turn
200                off, of course, like the way DECstation emulation works now.)
201    
202    PCI:
203            x)  last write was ffffffff ==> fix this, it should be used
204                together with a mask to get the correct bits. also, not ALL
205                bits are size bits! (lowest 4 vs lowest 2?)
206            x)  add support for address fixups
207            x)  generalize the interrupt routing stuff (lines etc). this should
208                be per machine? or per bus, that's better
209            x)  add a "pcn" NIC (AMD PCnet32 Lance 79c970 (PCI 1022:2000)),
210                could be useful for several machine modes (Malta, Algor, evbarm,
211                hp700?, macppc, etc.)
212    
213    Network layer:
214            o)  DHCP (for Debian and BSD installers :-)
215            o)  increase performance
216            o)  don't rely on NetBSD-ish usage
217            o)  Multiple networks per emulation, and let different
218                NICs in machines connect to different networks.
219            o)  many other issues: see src/net.c
220    
221    Busses:
222            o)  Redesign the entire "mainbus" concept!
223            o)  Busses should be placed in a hierarchical tree!
224            o)  Easily configurable interrupt routing in SMP systems.
225            o)  Specific clock/bus speeds, cpu speeds etc.
226            o)  Synchronization over network? or at least in dyntrans within
227                one emulated machine
228            o)  dev->bus: TurboChannel, PCMCIA, ADB?
229    
230    Config file parser:
231            o)  Rewrite it from scratch!
232            o)  Usage of any expression available through the debugger
233            o)  Support for running debugger commands (like the -c
234                command line option)
235    
236    Floating point layer:
237            o)  make it common enough to be used by _all_ emulation modes
238            o)  implement more stuff
239            o)  non-IEEE modes (i.e. x86)?
240    
241    Userland emulation:
242            x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
243            x)  Dynamic linking? Hm.
244    
245    Sound:
246            x)  generic sound framework
247            x)  add one or more sound cards as devices
248    
249    ASC SCSI controller:
250            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
251                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
252                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
253                2005/11/06/0024.html suggests that.)
254    
255    Caches / memory hierarchies: (this is mostly MIPS-specific)
256            o)  MIPS coproc.c: bits in config registers should reflect
257                correct cache sizes for _all_ CPU types. (currently only
258                implemented for R4000, R1x000, and a few others)
259            o)  src/memory*.c: Implement correct cache emulation for
260                all CPU types. (currently only R2000/R3000 is implemented)
261                (per CPU, multiple levels should be possible,
262                associativity etc!)
263            o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
264            o)  Move the -S (fill mem with random) functionality into the
265                memory.c subsystem, not machine.c or wherever it is now
266            o)  ECC stuff, simulation of memory errors?  (Machine dependent)
267            o)  More than 4GB of emulated RAM, when run on a 32-bit host?
268                (using manual swap-out of blocks to disk, ugly)
269            o)  A global command line option should be used to turn
270                cache emulation on or off. When off, caches should be
271                faked like they are right now. When on, caches and
272                memory latencies should be emulated as correctly as
273                possible.
274    
275    File/disk/symbol handling:
276            o)  Better handling of tape files
277            o)  Read function argument count and types from binaries? (ELF?)
278            o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
279                Microsoft's C++, so multiple schemes must be possible. See
280                URL at top of src/symbol_demangle.c for more info.
281    
282    Userland ABI emulation:
283            o)  see src/useremul.c
284    
285    Terminal/console:
286            o)  allow emulated serial ports to be connected to the outside
287                world in a more generic way, or even to other emulated
288                machines(?)
289    
290    Save state of the whole emulated machine, to be able to load it back
291            in later?  (Memory, all device's states, all registers and
292            so on.  Like taking a snapshot. (SimOS seems to do this,
293            according to its website.))
294    
295    Better framebuffer and X-windows functionality:
296            o)  -Yx sometimes causes crashes.
297            o)  Simple device access to framebuffer_blockcopyfill() etc,
298                and text output (using the built-in fonts), for dev_fb.
299            o)  CLEAN UP the ugly event code
300            o)  Mouse clicks can be "missed" in the current system; this is
301                not good. They should be put on a stack of some kind.
302            o)  More 2D and 3D framebuffer acceleration.
303            o)  Non-resizable windows?  Or choose scaledown depending
304                    on size (and center the image, with a black border).
305            o)  Different scaledown on different windows?
306            o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
307            o)  Bug reported by Elijah Rutschman on MacOS with weird
308                keys (F5 = cursor down?).
309            o)  Keyboard and mouse events:
310                    x)  Do this for more machines than just DECstation
311                    x)  more X11 cursor keycodes
312                    x)  Keys like CTRL, ALT, SHIFT do not get through
313                        by themselves (these are necessary for example
314                        to change the font of an xterm in X in the
315                        emulator)
316            o)  Generalize the framebuffer stuff by moving _ALL_ X11
317                    specific code to src/x11.c!
318    
319    Statistics:  (this could be interesting)
320            o)  Save to file and show graphics. It should be possible to
321                run gxemul after a simulation to just show the graphics,
322                or convert to a .ppm or .tga or similar.
323            o)  memory accesses (to measure cache efficiency and
324                    page coloring efficiency)
325            o)  nr of simultaneous ASIDs in use in the TLB, for MIPS
326            o)  percentage of time spent in different "states", such as
327                running userland code, kernel code, or idling (for CPUs
328                that have such an instruction, or whenever the PC is
329                inside a specific idle-function (address range)).
330                Possible additional state (for example on R3000): caches
331                disabled.
332            o)  position of read/write on (SCSI) disks
333    

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