/[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 10 by dpavlin, Mon Oct 8 16:18:27 2007 UTC revision 24 by dpavlin, Mon Oct 8 16:19:56 2007 UTC
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1  $Id: TODO,v 1.139 2005/06/23 06:55:43 debug Exp $  $Id: TODO,v 1.292 2006/06/23 09:13:34 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  Possible release schedule:
8                      implemented for R4000, R1x000, and a few others)  
9                  o)  src/memory*.c: Implement correct cache emulation for  0.4.0:
10                      all CPU types. (currently only R2000/R3000 is implemented)          x)  Quick release, even though performance for non-R3000 MIPS dyntrans
11                      (per CPU, multiple levels should be possible,              is really poor. (Assuming everything mentioned in the documentation
12                      associativity etc!)              works as expected.)
13                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)  
14                  o)  Move the -S (fill mem with random) functionality into the  0.4.1:
15                      memory.c subsystem, not machine.c or wherever it is now          x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
16                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)          x)  Fix the interrupt problems with Ultrix!
17                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          x)  Find/fix bug which is triggered when building the emulator inside
18                      (using manual swap-out of blocks to disk, ugly)              NetBSD/pmax 3.0 inside the emulator!
19                  o)  A global command line option should be used to turn  
20                      cache emulation on or off. When off, caches should be  0.4.2 ...?
21                      faked like they are right now. When on, caches and          x)  Clean-up!
22                      memory latencies should be emulated as correctly as          x)  Clock framework? Go through all clock devices, make sure they
23                      possible.              return correct data, and run at correct speeds!
24            x)  Optimizations, continuing on 64-bit issues etc with dyntrans
25          Network layer:          x)  Dyntrans with SMP... lots of work to be done here.
26                  o)  Multiple networks per emulation, and let different          x)  Dyntrans with cache emulation... lots of work here as well.
27                      NICs in machines connect to different networks.          x)  Actually use the settings object, better debugger stuff, etc.
28                  o)  many other issues: see src/net.c          x)  Wait for new releases of NetBSD, and test with those.
29    
30          CPU emulation:  --------------
31                  o)  Binary translation:  
32                          +)  use an Intermediate Representation!  SMP:
33                          +)  recursive translation?          o)  dev_mp doesn't work well with dyntrans yet
34                          +)  basic blocks instead of one-instruction? :)          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
35                          +)  on Alpha: don't assume pca56-like byte load/store?  
36                          +)  write backends for UltraSparc and MIPS  MIPS:
37                          +)  see src/bintrans.c for more info          o)  Fix invalidate_asid so it works well for non-R3000 too!
38                  o)  Dynamic-but-not-binary translation?          x)  [Re]add an interrupt-asserted bit for MIPS, to speed up
39                  o)  All the non-MIPS modes need a bit of work.              interrupt handling slightly?
40            +)  Print a warning on the first reserved instruction.
41          MIPS CPU emulation:          +)  Some more work on opcodes.
42                  o)  Instructions:                  x) MIPS64 revision 2.
43                          o)  Regression tests (see tests/README for more info):                  x) _MAYBE_ TX79 and R5900 actually differ in their
44                                  o)  Floating point exception handling, and                     opcodes? Check this carefully!
45                                          add more instructions.          o)  Dyntrans: Count register updates are probably not 100% correct yet.
46                                  o)  Finish the MIPS16 translator, and test it!          o)  Dyntrans: SMP correctness
47                                  o)  MIPS ISA I, II, III, IV          o)  Refactor code for performance and readability/maintainability.
48                                  o)  MIPS V (SIMD vector stuff?)          o)  Instruction combinations? Possible candidates (but profile first!):
49                                  o)  MDMX  (MIPS Digital Media Extension)                  o)  multiple loads/stores in a row
50                                  o)  MIPS 3D                  o)  strlen, memset loops etc
51                                  o)  MIPS MT (Multi-thread stuff) (What's this?)                  o)  compare + branch
52                          o)  Warn about mis-used bit fields (ie bits that          o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
53                              should be all zeroes, warn about if they are not)!              a rotation bit which differs from previous ISAs.
54                              Both for coprocessor registers and for instruction          o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
55                              opcodes.              _NOT_ the same as for R5900!
56                          o)  the special2 stuff is a mess right now          o)  R4000 and others:
57                          o)  warn and/or cause exceptions for unimplemented                  x)  watchhi/watchlo exceptions, and other exception
58                              instructions (depending on CPU type)                      handling details
59                  o)  R2000/R3000:          o)  R10000 and others:  (R12000, R14000 ?)
60                          x)  R3000 "tri-byte stores". (What's this?)                  x)  memory space, exceptions, ...
61                  o)  R4000 and others:                  x)  use cop0 framemask for tlb lookups
62                          x)  watchhi/watchlo exceptions, and other exception                      (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                              handling details  
64                  o)  R10000 and others:  (R12000, R14000 ?)  Dyntrans:
65                          x)  memory space, exceptions, ...          x)  Move the mips_init_64bit_dummy_tables() etc calls into
66                          x)  use cop0 framemask for tlb lookups              src/cpu.c, for all 64-bit cpus?
67                              (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)          x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably
68                  o)  Implement load delays?  Warnings on interlocks.                  help performance a bit.
69                  o)  Implement all coprocessor 0 bits / functions.          x)  Common fatal_abort() function, which drops into the debugger
70                          x)  coproc 0 selectors! (R4000 ?)                  without continuing.
71                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird          x)  INVALIDATION should cause translations in _all_ cpus to be
72                          TLB/cache? 128-bit GPRs, new instructions),              invalidated, e.g. on a write to a write-protected page
73                          4K (note: NOT R4000), 5K (note: NOT R5000),              (containing code)
74                          R6000 (ISA II), R8000          x)  better (formally defined) instr call statistics (-s command
75                  o)  Multi-cpu stuff:              line option?), multiple different types? (virtual pc, physical pc)
76                          +)  SGI's NUMA architecture. Study          x)  Call/return hints?
77                                  x)  Linux sources          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
78                                  x)  SGI's specs on NUMA address space          x)  H8?
79                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
80                          +)  Own experiments with ycx2.          x)  true recompilation backend? think carefully about this,
81                experiment in a separate project (not in GXemul)
82          Emulation of specific machines and devices:          x)  Remove the dyntrans_alignment_check functionality; although
83                  o)  Use same clock for all emulations and machines.              it gives slightly higher peformance sometimes, it increases
84                  o)  Clean up the device stuff (registering of devices etc)              the complexity of the code too much!
85                  o)  Various SCSI and IDE controllers  
86                  o)  PS/2-style keyboard controller (for several machines)  Alpha:
87                  o)  Generic busses;          o)  Virtual memory (tlbs etc)
88                          x)  PCI:  i/o and interrupts          o)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
89                          x)  QBus-22 (DECsystem 5500, 5400?)  
90                  o)  DECstations (pmax):  SPARC:
91                          x)  ioasic          o)  Add all registers (floating point, control regs etc)
92                          x)  framebuffers:          o)  Save/restore register windows etc!
93                                  +)  better cursor support, overlays?,          o)  Disassemly of some more instructions.
94                                  +)  2D/3D acceleration, PX[G]          o)  Are sll etc 32-bit sign-extending or zero-extending?
95                          x)  status words / control words, make this more          o)  Finish the cmp (subcc) flag computation code.
96                                  portable/cleaner          o)  Finish the GDB register stuff.
97                          x)  scsi controller(s): sii, DMA for asc  
98                          x)  serial controllers: ssc, scc (and more work on dc?)  Debugger:
99                          x)  nvram on decstation 5000/125:  when using X11,          o)  How does SMP debugging work? Does it simply use "threads"?
100                                  set console=g or similar                  What if the guest OS (running on an emulated SMP machine)
101                          x)  DECstation 5840? "xbi-based SMP"                  has a usertask running, with userland threads?
102                  o)  SGI and ARC machines (sgimips, arc):          o)  Try to make the debugger more modular and, if possible, reentrant!
103                          x)  IP32 ("O2"): (Lots of stuff)          o)  Remove the emul command? (But show network info if showing
104                                  +)  mec (ethernet)                  machines?)
105                                  +)  pci          o)  Generalize the expression evaluator. (debugger_expr.c?)
106                                  +)  ahc (scsi)                  settable variables      ("show nr of instructions on average")
107                                  +)  ps2 kbd                  emul[x]                 defaults to current emul
108                                  +)  memory controller                  machine[x]              defaults to current machine
109                                  +)  framebuffer/graphics                  cpu[x]                  defaults to currently focused cpu
110                                  +)  caches                  registers               cpu arch dependent (#-prefix)
111                          x)  more ARCBIOS stuff                  symbols                 @-prefix
112                          x)  Memory/interrupt controllers                  numeric constants       decimal, hex, and octal ($-prefix)
113                          x)  IP30 (Linux with graphics support?)                  boolean                 yes,no, true,false
114                          x)  SMP / NUMA?  (SGI and various ARC machines)                  operators (+ - * / % & | ^ !)
115                  o)  Playstation 2:                  parentheses for grouping subexpressions
116                          Hardware:  OHCI usb controller, keyboard, ...                  NOTE: the change from % to # for register prefix!
117                  o)  Less interesting platforms:                  examples:
118                          o)  newsmips:                                  emul[0].machine[2].cpu[0].pc
119                                  o)  NetBSD/newsmips, get it to detect a "real"                                  machine[test2].cpu[1].ra = main
120                                      model, right now everything is 100% bogus                                  settings.show_trace_tree = yes
121                          o)  mipsco? (NetBSD)  
122                          o)  wgrisc? (big endian R3000, in OpenBSD's attic)                  Settings:
123                          o)  other embedded / evaluation MIPS boards                          o)  Remove a setting.
124                          o)  Playstation 1? R3000A. Weird hardware?                          o)  Read/write a setting given a name. (Read as
125                                  No FPU, but something as coproc 2.                              string and/or int64_t simultaneously?)
126                          o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp  
127                                  (R4300, 4MB RAM, really weird memory map)                  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)  Read function argument count and types from binaries? (ELF?)          o)  see src/debugger.c for more
131                  o)  Better handling of tape files  
132    POWER/PowerPC:
133          Userland ABI emulation:          x)  PPC optimizations; instr combs
134                  o)  see src/useremul.c          x)  64-bit stuff
135            x)  find and fix the bug which causes NetBSD/macppc to fail after
136          Terminal based interactive debugger:              an install!
137                  o)  see src/debugger.c          x)  macppc: adb controller; keyboard (for framebuffer mode)
138            x)  make OpenBSD/macppc work (PCI controller stuff)
139          Terminal/console stuff:  
140                  o)  allow emulated serial ports to be connected to the outside  Algor:
141                      world in a more generic way, or even to other emulated          PCI and ISA and LOCAL interrupts! --> wdc could start working
142                      machines(!)          Add interrupt controller in dev_algor.c.
143    
144          Regression tests:  (Should be totally rewritten.)  ARM:
145                  o)  see tests/          o)  try to get netbsd/evbarm 3.x running (iq80321)
146            o)  make the xscale counter registers (ccnt) work
147          Save state of the whole emulated machine, to be able to load it back          o)  make the ata controller usable for FreeBSD!
148                  in later?  (Memory, all device's states, all registers and          o)  zaurus for openbsd...
149                  so on.  Like taking a snapshot. (SimOS seems to do this,          o)  debian/cats crashes because of unimplemented coproc stuff.
150                  according to its website.))              fix this?
151    
152          Better X-windows functionality:  Cache simulation:
153                  o)  CLEAN UP the ugly event code          o)  Separate from the CPU concept, so that multi-core CPUs sharing
154                  o)  Mouse clicks can be "missed" in the current system; this is              e.g. a L2 cache can be simulated (?)
155                      not good. They should be put on a stack of some kind.          o)  Instruction cache emulation is easiest (if separate from the
156                  o)  More 2D and 3D framebuffer acceleration.              data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
157                  o)  Non-resizable windows?  Or choose scaledown depending              NOTE: if the architecture has a delay slot, then an instruction
158                          on size (and center the image, with a black border).              slot can actually be executed as 2 instructions.
159                  o)  Different scaledown on different windows?          o)  Data cache emulation = harder; each arch's load/store routines
160                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)              must include support? running one instruction at a time and
161                  o)  Keyboard and mouse events:              having a cpu-dependant lookup function for each instruction
162                          x)  Do this for more machines than just DECstation              is another option (easier to implement, but very very slow).
163                          x)  more X11 cursor keycodes  
164                          x)  Keys like CTRL, ALT, SHIFT do not get through  Documentation:
165                              by themselves (these are necessary for example          o)  machines, cpus, devices.
166                              to change the font of an xterm in X in the          o)  Automagic documentation generation:
167                              emulator)                  x)  REMEMBER that several machines/devices can be in
168                  o)  Generalize the framebuffer stuff by moving _ALL_ X11                          the same source file!
169                          specific code to src/x11.c!          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          Statistics:  (this could be interesting)              ffs partition using up all of the disk image.)
172                  o)  Save to file and show graphics. It should be possible to  
173                      run gxemul after a simulation to just show the graphics,  More generic out_of_memory error reporting, and check everywhere!
174                      or convert to a .ppm or .tga or similar.          Causes: OpenBSD has low default limits for normal users.
175                  o)  memory accesses (to measure cache efficiency and                  Host is 32-bit? (32-bit hosts are limited to 4 GB or less
176                          page coloring efficiency)                  of userspace memory.)
177                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS                  You are actually low on RAM. (As trivial as this might sound,
178                  o)  percentage of time spent in different "states", such as                  Unix systems usually allow processes to allocate virtual
179                      running userland code, kernel code, or idling (for CPUs                  memory beyond the amount of RAM in the machine.)
180                      that have such an instruction, or whenever the PC is  
181                      inside a specific idle-function (address range)).  Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc.
182                      Possible additional state (for example on R3000): caches          Use the debugger's symbolic name stuff. (which will have to be
183                      disabled.          extended soon to support stuff like  "2*x + symbol + y" etc. cool
184                  o)  position of read/write on (SCSI) disks          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:
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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