/[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 14 by dpavlin, Mon Oct 8 16:18:51 2007 UTC revision 26 by dpavlin, Mon Oct 8 16:20:10 2007 UTC
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1  $Id: TODO,v 1.173 2005/09/17 17:14:25 debug Exp $  $Id: TODO,v 1.298 2006/06/25 11:08:04 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:  --------------
   
   
 Old MIPS bintrans:  
   
         x)  call/return address cache?  
   
         x)  Turn the MIPS cpu family stuff into dyntrans.  
6    
7            x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
8            x)  Find a way to get rid of the cpu_create_or_reset_tc in the
9                R2000/R3000 cache isolation code. (NetBSD works without it,
10                but not Ultrix and Linux yet.)
11            x)  Formalize the statistics gathering stuff for dyntrans...
12            x)  ... and use it to optimize MIPS dyntrans stuff.
13            x)  Clock framework? Go through all clock devices, make sure they
14                return correct data, and run at correct speeds!
15            x)  Optimizations, continuing on 64-bit issues etc with dyntrans
16            x)  Dyntrans with SMP... lots of work to be done here.
17            x)  Dyntrans with cache emulation... lots of work here as well.
18            x)  Actually use the settings object, better debugger stuff, etc.
19            x)  Wait for new releases of NetBSD, and test with those.
20    
21    --------------
22    
23    SMP:
24            o)  dev_mp doesn't work well with dyntrans yet
25            o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
26    
27    MIPS:
28            o)  Fix invalidate_asid so it works well for non-R3000 too!
29            x)  [Re]add an interrupt-asserted bit for MIPS, to speed up
30                interrupt handling slightly?
31            +)  Print a warning on the first reserved instruction.
32            +)  Some more work on opcodes.
33                    x) MIPS64 revision 2.
34                    x) _MAYBE_ TX79 and R5900 actually differ in their
35                       opcodes? Check this carefully!
36            o)  Dyntrans: Count register updates are probably not 100% correct yet.
37            o)  Dyntrans: SMP correctness
38            o)  Refactor code for performance and readability/maintainability.
39            o)  Instruction combinations? Possible candidates (but profile first!):
40                    o)  multiple loads/stores in a row
41                    o)  strlen, memset loops etc
42                    o)  compare + branch
43            o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
44                a rotation bit which differs from previous ISAs.
45            o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
46                _NOT_ the same as for R5900!
47            o)  R4000 and others:
48                    x)  watchhi/watchlo exceptions, and other exception
49                        handling details
50            o)  R10000 and others:  (R12000, R14000 ?)
51                    x)  memory space, exceptions, ...
52                    x)  use cop0 framemask for tlb lookups
53                        (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    
55  Dyntrans:  Dyntrans:
56            x)  Move the mips_init_64bit_dummy_tables() etc calls into
57          x)  Lots of stuff: see src/cpus/README_DYNTRANS              src/cpu.c, for all 64-bit cpus?
58            x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably
59                    help performance a bit.
60            x)  Common fatal_abort() function, which drops into the debugger
61                    without continuing.
62            x)  INVALIDATION should cause translations in _all_ cpus to be
63                invalidated, e.g. on a write to a write-protected page
64                (containing code)
65            x)  better (formally defined) instr call statistics (-s command
66                line option?), multiple different types? (virtual pc, physical pc)
67            x)  Call/return hints?
68            x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
69            x)  H8?
70            x)  Lots of other stuff: see src/cpus/README_DYNTRANS
71            x)  true recompilation backend? think carefully about this,
72                experiment in a separate project (not in GXemul)
73            x)  Remove the dyntrans_alignment_check functionality; although
74                it gives slightly higher peformance sometimes, it increases
75                the complexity of the code too much!
76    
77    Alpha:
78            o)  Virtual memory (tlbs etc)
79            o)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
80    
81    SPARC:
82            o)  Add all registers (floating point, control regs etc)
83            o)  Save/restore register windows etc!
84            o)  Disassemly of some more instructions.
85            o)  Are sll etc 32-bit sign-extending or zero-extending?
86            o)  Finish the cmp (subcc) flag computation code.
87            o)  Finish the GDB register stuff.
88    
89    Debugger:
90            o)  How does SMP debugging work? Does it simply use "threads"?
91                    What if the guest OS (running on an emulated SMP machine)
92                    has a usertask running, with userland threads?
93            o)  Try to make the debugger more modular and, if possible, reentrant!
94            o)  Remove the emul command? (But show network info if showing
95                    machines?)
96            o)  Generalize the expression evaluator. (debugger_expr.c?)
97                    settable variables      ("show nr of instructions on average")
98                    emul[x]                 defaults to current emul
99                    machine[x]              defaults to current machine
100                    cpu[x]                  defaults to currently focused cpu
101                    registers               cpu arch dependent (#-prefix)
102                    symbols                 @-prefix
103                    numeric constants       decimal, hex, and octal ($-prefix)
104                    boolean                 yes,no, true,false
105                    operators (+ - * / % & | ^ !)
106                    parentheses for grouping subexpressions
107                    NOTE: the change from % to # for register prefix!
108                    examples:
109                                    emul[0].machine[2].cpu[0].pc
110                                    machine[test2].cpu[1].ra = main
111                                    settings.show_trace_tree = yes
112    
113                    Settings:
114                            o)  Remove a setting.
115                            o)  Read/write a setting given a name. (Read as
116                                string and/or int64_t simultaneously?)
117    
118                    Help command should have subsections! One for "expressions",
119                    mirrored in the documentation, but the internal help should
120                    be the one that should be considered correct.
121            o)  see src/debugger.c for more
122    
123    POWER/PowerPC:
124            x)  PPC optimizations; instr combs
125            x)  64-bit stuff
126            x)  find and fix the bug which causes NetBSD/macppc to fail after
127                an install!
128            x)  macppc: adb controller; keyboard (for framebuffer mode)
129            x)  make OpenBSD/macppc work (PCI controller stuff)
130    
131    Algor:
132            PCI and ISA and LOCAL interrupts! --> wdc could start working
133            Add interrupt controller in dev_algor.c.
134    
135    ARM:
136            o)  try to get netbsd/evbarm 3.x running (iq80321)
137            o)  make the xscale counter registers (ccnt) work
138            o)  make the ata controller usable for FreeBSD!
139            o)  zaurus for openbsd...
140            o)  debian/cats crashes because of unimplemented coproc stuff.
141                fix this?
142    
143    Cache simulation:
144            o)  Separate from the CPU concept, so that multi-core CPUs sharing
145                e.g. a L2 cache can be simulated (?)
146            o)  Instruction cache emulation is easiest (if separate from the
147                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
148                NOTE: if the architecture has a delay slot, then an instruction
149                slot can actually be executed as 2 instructions.
150            o)  Data cache emulation = harder; each arch's load/store routines
151                must include support? running one instruction at a time and
152                having a cpu-dependant lookup function for each instruction
153                is another option (easier to implement, but very very slow).
154    
155    Documentation:
156            o)  machines, cpus, devices.
157            o)  Automagic documentation generation:
158                    x)  REMEMBER that several machines/devices can be in
159                            the same source file!
160            o)  Try to rewrite the install instructions for those machines
161                that use 3MAX into using CATS? (To remove the need to a raw
162                ffs partition using up all of the disk image.)
163    
164    More generic out_of_memory error reporting, and check everywhere!
165            Causes: OpenBSD has low default limits for normal users.
166                    Host is 32-bit? (32-bit hosts are limited to 4 GB or less
167                    of userspace memory.)
168                    You are actually low on RAM. (As trivial as this might sound,
169                    Unix systems usually allow processes to allocate virtual
170                    memory beyond the amount of RAM in the machine.)
171    
172    Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc.
173            Use the debugger's symbolic name stuff. (which will have to be
174            extended soon to support stuff like  "2*x + symbol + y" etc. cool
175            stuff)
176    
177    Sprite (guest OS for DECstation emulation)
178            x)  Timing problems during bootup?
179    
180    The Device subsystem:
181            x)  allow devices to be moved and/or changed in size (down to a
182                minimum size, etc, or up to a max size)
183            x)  keep track of interrupts and busses? actually, allowing any device
184                to be a bus might be a nice idea.
185            x)  turn interrupt controllers into devices? :-)
186            x)  refactor various clocks/nvram/cmos into one device?
187    
188    Clocks:
189            x)  General framework for automagic clock adjustment for _all_
190                kinds of clocks and timers. (Which should be possible to turn
191                off, of course, like the way DECstation emulation works now.)
192    
193    PCI:
194            x)  last write was ffffffff ==> fix this, it should be used
195                together with a mask to get the correct bits. also, not ALL
196                bits are size bits! (lowest 4 vs lowest 2?)
197            x)  add support for address fixups
198            x)  generalize the interrupt routing stuff (lines etc). this should
199                be per machine? or per bus, that's better
200            x)  add a "pcn" NIC (AMD PCnet32 Lance 79c970 (PCI 1022:2000)),
201                could be useful for several machine modes (Malta, Algor, evbarm,
202                hp700?, macppc, etc.)
203    
204    Network layer:
205            o)  DHCP (for Debian and BSD installers :-)
206            o)  increase performance
207            o)  don't rely on NetBSD-ish usage
208            o)  Multiple networks per emulation, and let different
209                NICs in machines connect to different networks.
210            o)  many other issues: see src/net.c
211    
212    Busses:
213            o)  Redesign the entire "mainbus" concept!
214            o)  Busses should be placed in a hierarchical tree!
215            o)  Easily configurable interrupt routing in SMP systems.
216            o)  Specific clock/bus speeds, cpu speeds etc.
217            o)  Synchronization over network? or at least in dyntrans within
218                one emulated machine
219            o)  dev->bus: TurboChannel, PCMCIA, ADB?
220    
221    Config file parser:
222            o)  Rewrite it from scratch!
223            o)  Usage of any expression available through the debugger
224            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:  Userland emulation:
233            x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
         x)  Lots of stuff.  
   
234          x)  Dynamic linking? Hm.          x)  Dynamic linking? Hm.
235    
236  ===============================================================================  Sound:
237            x)  generic sound framework
238  Lower priority, but still important:          x)  add one or more sound cards as devices
239    
240          Redesign the entire "mainbus" concept:  ASC SCSI controller:
241                  o)  Easily configurable interrupt routing in SMP systems.          x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
242                  o)  Specific clock/bus speeds, cpu speeds etc.              cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
243                  o)  Synchronization over network?              in NetBSD itself, http://mail-index.netbsd.org/source-changes/
244                2005/11/06/0024.html suggests that.)
245          Caches / memory hierarchies: (this is mostly MIPS-specific)  
246                  o)  MIPS coproc.c: bits in config registers should reflect  Caches / memory hierarchies: (this is mostly MIPS-specific)
247                      correct cache sizes for _all_ CPU types. (currently only          o)  MIPS coproc.c: bits in config registers should reflect
248                      implemented for R4000, R1x000, and a few others)              correct cache sizes for _all_ CPU types. (currently only
249                  o)  src/memory*.c: Implement correct cache emulation for              implemented for R4000, R1x000, and a few others)
250                      all CPU types. (currently only R2000/R3000 is implemented)          o)  src/memory*.c: Implement correct cache emulation for
251                      (per CPU, multiple levels should be possible,              all CPU types. (currently only R2000/R3000 is implemented)
252                      associativity etc!)              (per CPU, multiple levels should be possible,
253                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)              associativity etc!)
254                  o)  Move the -S (fill mem with random) functionality into the          o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
255                      memory.c subsystem, not machine.c or wherever it is now          o)  Move the -S (fill mem with random) functionality into the
256                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)              memory.c subsystem, not machine.c or wherever it is now
257                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          o)  ECC stuff, simulation of memory errors?  (Machine dependent)
258                      (using manual swap-out of blocks to disk, ugly)          o)  More than 4GB of emulated RAM, when run on a 32-bit host?
259                  o)  A global command line option should be used to turn              (using manual swap-out of blocks to disk, ugly)
260                      cache emulation on or off. When off, caches should be          o)  A global command line option should be used to turn
261                      faked like they are right now. When on, caches and              cache emulation on or off. When off, caches should be
262                      memory latencies should be emulated as correctly as              faked like they are right now. When on, caches and
263                      possible.              memory latencies should be emulated as correctly as
264                possible.
265          Network layer:  
266                  o)  Multiple networks per emulation, and let different  File/disk/symbol handling:
267                      NICs in machines connect to different networks.          o)  Better handling of tape files
268                  o)  many other issues: see src/net.c          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          MIPS CPU emulation:              Microsoft's C++, so multiple schemes must be possible. See
271                  o)  i386 bintrans backend: movn etc, slt[u] for              URL at top of src/symbol_demangle.c for more info.
272                          64-bit mode, 64-bit shifts etc  
273                  o)  Instructions:  Userland ABI emulation:
274                          o)  All ISAs:          o)  see src/useremul.c
275                                  o)  Floating point exception handling, and  
276                                          add more instructions.  Terminal/console:
277                                  o)  Finish the MIPS16 translator, and test it!          o)  allow emulated serial ports to be connected to the outside
278                                  o)  MIPS ISA I, II, III, IV              world in a more generic way, or even to other emulated
279                                  o)  MIPS V (SIMD vector stuff?)              machines(?)
280                                  o)  MDMX  (MIPS Digital Media Extension)  
281                                  o)  MIPS 3D  Save state of the whole emulated machine, to be able to load it back
282                                  o)  MIPS MT (Multi-thread stuff) (What's this?)          in later?  (Memory, all device's states, all registers and
283                          o)  Warn about mis-used bit fields (ie bits that          so on.  Like taking a snapshot. (SimOS seems to do this,
284                              should be all zeroes, warn about if they are not)!          according to its website.))
285                              Both for coprocessor registers and for instruction  
286                              opcodes.  Better framebuffer and X-windows functionality:
287                          o)  the special2 stuff is a mess right now          o)  -Yx sometimes causes crashes.
288                          o)  warn and/or cause exceptions for unimplemented          o)  Simple device access to framebuffer_blockcopyfill() etc,
289                              instructions (depending on CPU type)              and text output (using the built-in fonts), for dev_fb.
290                  o)  R2000/R3000:          o)  CLEAN UP the ugly event code
291                          x)  R3000 "tri-byte stores". (What's this?)          o)  Mouse clicks can be "missed" in the current system; this is
292                  o)  R4000 and others:              not good. They should be put on a stack of some kind.
293                          x)  watchhi/watchlo exceptions, and other exception          o)  More 2D and 3D framebuffer acceleration.
294                              handling details          o)  Non-resizable windows?  Or choose scaledown depending
295                  o)  R10000 and others:  (R12000, R14000 ?)                  on size (and center the image, with a black border).
296                          x)  memory space, exceptions, ...          o)  Different scaledown on different windows?
297                          x)  use cop0 framemask for tlb lookups          o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
298                              (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)  Bug reported by Elijah Rutschman on MacOS with weird
299                  o)  Implement load delays?  Warnings on interlocks.              keys (F5 = cursor down?).
300                  o)  Implement all coprocessor 0 bits / functions.          o)  Keyboard and mouse events:
301                          x)  coproc 0 selectors! (R4000 ?)                  x)  Do this for more machines than just DECstation
302                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird                  x)  more X11 cursor keycodes
303                          TLB/cache? 128-bit GPRs, new instructions),                  x)  Keys like CTRL, ALT, SHIFT do not get through
304                          4K (note: NOT R4000), 5K (note: NOT R5000),                      by themselves (these are necessary for example
305                          R6000 (ISA II), R8000                      to change the font of an xterm in X in the
306                  o)  Multi-cpu stuff:                      emulator)
307                          +)  Interrupt routing (ie devices vs mainbus, or          o)  Generalize the framebuffer stuff by moving _ALL_ X11
308                              connect each device to a fixed cpu)                  specific code to src/x11.c!
309                          +)  SGI's NUMA architecture. Study  
310                                  x)  Linux sources  Statistics:  (this could be interesting)
311                                  x)  SGI's specs on NUMA address space          o)  Save to file and show graphics. It should be possible to
312                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(              run gxemul after a simulation to just show the graphics,
313                          +)  Own experiments with ycx2.              or convert to a .ppm or .tga or similar.
314            o)  memory accesses (to measure cache efficiency and
315          File/disk handling:                  page coloring efficiency)
316                  o)  Better handling of tape files          o)  nr of simultaneous ASIDs in use in the TLB, for MIPS
317            o)  percentage of time spent in different "states", such as
318          Debugger:              running userland code, kernel code, or idling (for CPUs
319                  o)  Read function argument count and types from binaries? (ELF?)              that have such an instruction, or whenever the PC is
320                  o)  Demangle C++ names.              inside a specific idle-function (address range)).
321                  o)  see src/debugger.c for more stuff              Possible additional state (for example on R3000): caches
322                disabled.
323          Userland ABI emulation:          o)  position of read/write on (SCSI) disks
                 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  
324    

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