/[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 24 by dpavlin, Mon Oct 8 16:19:56 2007 UTC
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1  $Id: TODO,v 1.173 2005/09/17 17:14:25 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  Old MIPS bintrans:  0.4.0:
10            x)  Quick release, even though performance for non-R3000 MIPS dyntrans
11          x)  call/return address cache?              is really poor. (Assuming everything mentioned in the documentation
12                works as expected.)
13          x)  Turn the MIPS cpu family stuff into dyntrans.  
14    0.4.1:
15            x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
16            x)  Fix the interrupt problems with Ultrix!
17            x)  Find/fix bug which is triggered when building the emulator inside
18                NetBSD/pmax 3.0 inside the emulator!
19    
20    0.4.2 ...?
21            x)  Clean-up!
22            x)  Clock framework? Go through all clock devices, make sure they
23                return correct data, and run at correct speeds!
24            x)  Optimizations, continuing on 64-bit issues etc with dyntrans
25            x)  Dyntrans with SMP... lots of work to be done here.
26            x)  Dyntrans with cache emulation... lots of work here as well.
27            x)  Actually use the settings object, better debugger stuff, etc.
28            x)  Wait for new releases of NetBSD, and test with those.
29    
30    --------------
31    
32    SMP:
33            o)  dev_mp doesn't work well with dyntrans yet
34            o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
35    
36    MIPS:
37            o)  Fix invalidate_asid so it works well for non-R3000 too!
38            x)  [Re]add an interrupt-asserted bit for MIPS, to speed up
39                interrupt handling slightly?
40            +)  Print a warning on the first reserved instruction.
41            +)  Some more work on opcodes.
42                    x) MIPS64 revision 2.
43                    x) _MAYBE_ TX79 and R5900 actually differ in their
44                       opcodes? Check this carefully!
45            o)  Dyntrans: Count register updates are probably not 100% correct yet.
46            o)  Dyntrans: SMP correctness
47            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            o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
53                a rotation bit which differs from previous ISAs.
54            o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
55                _NOT_ the same as for R5900!
56            o)  R4000 and others:
57                    x)  watchhi/watchlo exceptions, and other exception
58                        handling details
59            o)  R10000 and others:  (R12000, R14000 ?)
60                    x)  memory space, exceptions, ...
61                    x)  use cop0 framemask for tlb lookups
62                        (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    
64  Dyntrans:  Dyntrans:
65            x)  Move the mips_init_64bit_dummy_tables() etc calls into
66          x)  Lots of stuff: see src/cpus/README_DYNTRANS              src/cpu.c, for all 64-bit cpus?
67            x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably
68                    help performance a bit.
69            x)  Common fatal_abort() function, which drops into the debugger
70                    without continuing.
71            x)  INVALIDATION should cause translations in _all_ cpus to be
72                invalidated, e.g. on a write to a write-protected page
73                (containing code)
74            x)  better (formally defined) instr call statistics (-s command
75                line option?), multiple different types? (virtual pc, physical pc)
76            x)  Call/return hints?
77            x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
78            x)  H8?
79            x)  Lots of other stuff: see src/cpus/README_DYNTRANS
80            x)  true recompilation backend? think carefully about this,
81                experiment in a separate project (not in GXemul)
82            x)  Remove the dyntrans_alignment_check functionality; although
83                it gives slightly higher peformance sometimes, it increases
84                the complexity of the code too much!
85    
86    Alpha:
87            o)  Virtual memory (tlbs etc)
88            o)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
89    
90    SPARC:
91            o)  Add all registers (floating point, control regs etc)
92            o)  Save/restore register windows etc!
93            o)  Disassemly of some more instructions.
94            o)  Are sll etc 32-bit sign-extending or zero-extending?
95            o)  Finish the cmp (subcc) flag computation code.
96            o)  Finish the GDB register stuff.
97    
98    Debugger:
99            o)  How does SMP debugging work? Does it simply use "threads"?
100                    What if the guest OS (running on an emulated SMP machine)
101                    has a usertask running, with userland threads?
102            o)  Try to make the debugger more modular and, if possible, reentrant!
103            o)  Remove the emul command? (But show network info if showing
104                    machines?)
105            o)  Generalize the expression evaluator. (debugger_expr.c?)
106                    settable variables      ("show nr of instructions on average")
107                    emul[x]                 defaults to current emul
108                    machine[x]              defaults to current machine
109                    cpu[x]                  defaults to currently focused cpu
110                    registers               cpu arch dependent (#-prefix)
111                    symbols                 @-prefix
112                    numeric constants       decimal, hex, and octal ($-prefix)
113                    boolean                 yes,no, true,false
114                    operators (+ - * / % & | ^ !)
115                    parentheses for grouping subexpressions
116                    NOTE: the change from % to # for register prefix!
117                    examples:
118                                    emul[0].machine[2].cpu[0].pc
119                                    machine[test2].cpu[1].ra = main
120                                    settings.show_trace_tree = yes
121    
122                    Settings:
123                            o)  Remove a setting.
124                            o)  Read/write a setting given a name. (Read as
125                                string and/or int64_t simultaneously?)
126    
127                    Help command should have subsections! One for "expressions",
128                    mirrored in the documentation, but the internal help should
129                    be the one that should be considered correct.
130            o)  see src/debugger.c for more
131    
132    POWER/PowerPC:
133            x)  PPC optimizations; instr combs
134            x)  64-bit stuff
135            x)  find and fix the bug which causes NetBSD/macppc to fail after
136                an install!
137            x)  macppc: adb controller; keyboard (for framebuffer mode)
138            x)  make OpenBSD/macppc work (PCI controller stuff)
139    
140    Algor:
141            PCI and ISA and LOCAL interrupts! --> wdc could start working
142            Add interrupt controller in dev_algor.c.
143    
144    ARM:
145            o)  try to get netbsd/evbarm 3.x running (iq80321)
146            o)  make the xscale counter registers (ccnt) work
147            o)  make the ata controller usable for FreeBSD!
148            o)  zaurus for openbsd...
149            o)  debian/cats crashes because of unimplemented coproc stuff.
150                fix this?
151    
152    Cache simulation:
153            o)  Separate from the CPU concept, so that multi-core CPUs sharing
154                e.g. a L2 cache can be simulated (?)
155            o)  Instruction cache emulation is easiest (if separate from the
156                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
157                NOTE: if the architecture has a delay slot, then an instruction
158                slot can actually be executed as 2 instructions.
159            o)  Data cache emulation = harder; each arch's load/store routines
160                must include support? running one instruction at a time and
161                having a cpu-dependant lookup function for each instruction
162                is another option (easier to implement, but very very slow).
163    
164    Documentation:
165            o)  machines, cpus, devices.
166            o)  Automagic documentation generation:
167                    x)  REMEMBER that several machines/devices can be in
168                            the same source file!
169            o)  Try to rewrite the install instructions for those machines
170                that use 3MAX into using CATS? (To remove the need to a raw
171                ffs partition using up all of the disk image.)
172    
173    More generic out_of_memory error reporting, and check everywhere!
174            Causes: OpenBSD has low default limits for normal users.
175                    Host is 32-bit? (32-bit hosts are limited to 4 GB or less
176                    of userspace memory.)
177                    You are actually low on RAM. (As trivial as this might sound,
178                    Unix systems usually allow processes to allocate virtual
179                    memory beyond the amount of RAM in the machine.)
180    
181    Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc.
182            Use the debugger's symbolic name stuff. (which will have to be
183            extended soon to support stuff like  "2*x + symbol + y" etc. cool
184            stuff)
185    
186    Sprite (guest OS for DECstation emulation)
187            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:  Userland emulation:
242            x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
         x)  Lots of stuff.  
   
243          x)  Dynamic linking? Hm.          x)  Dynamic linking? Hm.
244    
245  ===============================================================================  Sound:
246            x)  generic sound framework
247  Lower priority, but still important:          x)  add one or more sound cards as devices
248    
249          Redesign the entire "mainbus" concept:  ASC SCSI controller:
250                  o)  Easily configurable interrupt routing in SMP systems.          x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
251                  o)  Specific clock/bus speeds, cpu speeds etc.              cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
252                  o)  Synchronization over network?              in NetBSD itself, http://mail-index.netbsd.org/source-changes/
253                2005/11/06/0024.html suggests that.)
254          Caches / memory hierarchies: (this is mostly MIPS-specific)  
255                  o)  MIPS coproc.c: bits in config registers should reflect  Caches / memory hierarchies: (this is mostly MIPS-specific)
256                      correct cache sizes for _all_ CPU types. (currently only          o)  MIPS coproc.c: bits in config registers should reflect
257                      implemented for R4000, R1x000, and a few others)              correct cache sizes for _all_ CPU types. (currently only
258                  o)  src/memory*.c: Implement correct cache emulation for              implemented for R4000, R1x000, and a few others)
259                      all CPU types. (currently only R2000/R3000 is implemented)          o)  src/memory*.c: Implement correct cache emulation for
260                      (per CPU, multiple levels should be possible,              all CPU types. (currently only R2000/R3000 is implemented)
261                      associativity etc!)              (per CPU, multiple levels should be possible,
262                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)              associativity etc!)
263                  o)  Move the -S (fill mem with random) functionality into the          o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
264                      memory.c subsystem, not machine.c or wherever it is now          o)  Move the -S (fill mem with random) functionality into the
265                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)              memory.c subsystem, not machine.c or wherever it is now
266                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          o)  ECC stuff, simulation of memory errors?  (Machine dependent)
267                      (using manual swap-out of blocks to disk, ugly)          o)  More than 4GB of emulated RAM, when run on a 32-bit host?
268                  o)  A global command line option should be used to turn              (using manual swap-out of blocks to disk, ugly)
269                      cache emulation on or off. When off, caches should be          o)  A global command line option should be used to turn
270                      faked like they are right now. When on, caches and              cache emulation on or off. When off, caches should be
271                      memory latencies should be emulated as correctly as              faked like they are right now. When on, caches and
272                      possible.              memory latencies should be emulated as correctly as
273                possible.
274          Network layer:  
275                  o)  Multiple networks per emulation, and let different  File/disk/symbol handling:
276                      NICs in machines connect to different networks.          o)  Better handling of tape files
277                  o)  many other issues: see src/net.c          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          MIPS CPU emulation:              Microsoft's C++, so multiple schemes must be possible. See
280                  o)  i386 bintrans backend: movn etc, slt[u] for              URL at top of src/symbol_demangle.c for more info.
281                          64-bit mode, 64-bit shifts etc  
282                  o)  Instructions:  Userland ABI emulation:
283                          o)  All ISAs:          o)  see src/useremul.c
284                                  o)  Floating point exception handling, and  
285                                          add more instructions.  Terminal/console:
286                                  o)  Finish the MIPS16 translator, and test it!          o)  allow emulated serial ports to be connected to the outside
287                                  o)  MIPS ISA I, II, III, IV              world in a more generic way, or even to other emulated
288                                  o)  MIPS V (SIMD vector stuff?)              machines(?)
289                                  o)  MDMX  (MIPS Digital Media Extension)  
290                                  o)  MIPS 3D  Save state of the whole emulated machine, to be able to load it back
291                                  o)  MIPS MT (Multi-thread stuff) (What's this?)          in later?  (Memory, all device's states, all registers and
292                          o)  Warn about mis-used bit fields (ie bits that          so on.  Like taking a snapshot. (SimOS seems to do this,
293                              should be all zeroes, warn about if they are not)!          according to its website.))
294                              Both for coprocessor registers and for instruction  
295                              opcodes.  Better framebuffer and X-windows functionality:
296                          o)  the special2 stuff is a mess right now          o)  -Yx sometimes causes crashes.
297                          o)  warn and/or cause exceptions for unimplemented          o)  Simple device access to framebuffer_blockcopyfill() etc,
298                              instructions (depending on CPU type)              and text output (using the built-in fonts), for dev_fb.
299                  o)  R2000/R3000:          o)  CLEAN UP the ugly event code
300                          x)  R3000 "tri-byte stores". (What's this?)          o)  Mouse clicks can be "missed" in the current system; this is
301                  o)  R4000 and others:              not good. They should be put on a stack of some kind.
302                          x)  watchhi/watchlo exceptions, and other exception          o)  More 2D and 3D framebuffer acceleration.
303                              handling details          o)  Non-resizable windows?  Or choose scaledown depending
304                  o)  R10000 and others:  (R12000, R14000 ?)                  on size (and center the image, with a black border).
305                          x)  memory space, exceptions, ...          o)  Different scaledown on different windows?
306                          x)  use cop0 framemask for tlb lookups          o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
307                              (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
308                  o)  Implement load delays?  Warnings on interlocks.              keys (F5 = cursor down?).
309                  o)  Implement all coprocessor 0 bits / functions.          o)  Keyboard and mouse events:
310                          x)  coproc 0 selectors! (R4000 ?)                  x)  Do this for more machines than just DECstation
311                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird                  x)  more X11 cursor keycodes
312                          TLB/cache? 128-bit GPRs, new instructions),                  x)  Keys like CTRL, ALT, SHIFT do not get through
313                          4K (note: NOT R4000), 5K (note: NOT R5000),                      by themselves (these are necessary for example
314                          R6000 (ISA II), R8000                      to change the font of an xterm in X in the
315                  o)  Multi-cpu stuff:                      emulator)
316                          +)  Interrupt routing (ie devices vs mainbus, or          o)  Generalize the framebuffer stuff by moving _ALL_ X11
317                              connect each device to a fixed cpu)                  specific code to src/x11.c!
318                          +)  SGI's NUMA architecture. Study  
319                                  x)  Linux sources  Statistics:  (this could be interesting)
320                                  x)  SGI's specs on NUMA address space          o)  Save to file and show graphics. It should be possible to
321                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(              run gxemul after a simulation to just show the graphics,
322                          +)  Own experiments with ycx2.              or convert to a .ppm or .tga or similar.
323            o)  memory accesses (to measure cache efficiency and
324          File/disk handling:                  page coloring efficiency)
325                  o)  Better handling of tape files          o)  nr of simultaneous ASIDs in use in the TLB, for MIPS
326            o)  percentage of time spent in different "states", such as
327          Debugger:              running userland code, kernel code, or idling (for CPUs
328                  o)  Read function argument count and types from binaries? (ELF?)              that have such an instruction, or whenever the PC is
329                  o)  Demangle C++ names.              inside a specific idle-function (address range)).
330                  o)  see src/debugger.c for more stuff              Possible additional state (for example on R3000): caches
331                disabled.
332          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  
333    

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