/[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 22 by dpavlin, Mon Oct 8 16:19:37 2007 UTC revision 30 by dpavlin, Mon Oct 8 16:20:40 2007 UTC
# Line 1  Line 1 
1  $Id: TODO,v 1.209 2006/02/18 21:03:09 debug Exp $  $Id: TODO,v 1.343 2006/08/14 18:46:30 debug Exp $
2    
3  Hm. This file is in random order, and not all parts of it are up-to-date.  Hm. This file is in random order, and not all parts of it are up-to-date.
4    
5  Algor:  PCI and ISA and LOCAL interrupts! --> wdc could start working  
6          Add interrupt controller in dev_algor.c.  Implementation:
7            x)  ARM "wait"-like instruction.
8            x)  CLOCK FRAMEWORK!
9            x)  Mouse support for NetBSD/pmax 4.x!
10            x)  See netwinder_reset() in NetBSD; the current "an internal error
11                occured" message after reboot/halt is too ugly.
12            x)  64-bit ranges in src/cpus/memory_mips_v2p.c
13            x)  Revert the dyntrans page template experiment? Hm.
14            x)  Refactor the cpu type detection/initialization/listing.
15                    Macro, which can be used as long as the cpu definitions
16                    contain a 'name'?
17            x)  Testmachine includes:
18                    + dev_fb block fill and copy
19                    + dev_fb draw characters (from the built-in font)?
20                    + dev_fb input device? mouse pointer coordinates and buttons
21                            (allow changes in these to cause interrupts as well?)
22                    + Redefine the halt() function so that it stops "sometimes
23                      soon", i.e. usage in demo code should be:
24                            for (;;) {
25                                    halt();
26                            }
27            x)  Continue on SPARC emulation
28                    + Enable it in the configure script as soon as it can
29                      run all the demo programs.
30            x)  Continue on Alpha emulation  (virtual memory, etc). Cleanup.
31            x)  Nicer MIPS status bits in register dumps.
32            x)  Alignment exceptions (MIPS, PPC, ARM?, ...)
33            x)  Rewrite the networking stack; make OpenBSD work better as a guest
34                OS, fix the performance problems, make Linux work with DHCP, etc.
35                Support VDE (vde.sf.net)? Allow SLIP connections, possibly PPP,
36                in addition to ethernet?
37            x)  Implement more ethernet NICs.
38            x)  IOP (I2O) device?
39    
40    Documentation:
41            x)  "Install netbsd/pmax first" => only use the install kernel?
42            x)  Rewrite the section about experimental devices, after the
43                framebuffer acceleration has been implemented, and demos
44                written. (Symbolic names instead of numbers; example
45                use cases, etc. Mention demo files that use the various
46                features?)
47            x)  "a very simple linear framebuffer device (for graphics output)"
48                under "which machines does gxemul emulate" ==> better
49                description?
50            x)  Better description on how to set up a cross compiler?
51                Example for MIPS64.
52    
53    Long-term design:
54            x)  Instruction combination collisions? How to avoid easily...
55            x)  Think about how to do both SHmedia and SHcompact in a reasonable
56                way!
57            o)  Actually use the settings object, better debugger stuff, etc!
58            o)  Debugger command for enabling/disabling instruction statistics
59                during runtime.   machine.statistics = on|off
60            x)  MAINBUS REDESIGN!
61            x)  PCI redesign... I need to read up on how PCI actually works :)
62            x)  Clock framework! Go through all clock devices, make sure they
63                return correct data, and run at correct speeds!
64            x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
65                it would be reasonably simple to add; in each individual fast
66                load/store routine = a lot more work, and it would become
67                kludgy very fast.)
68            x)  Dyntrans with SMP... lots of work to be done here.
69            x)  Dyntrans with cache emulation... lots of work here as well.
70            x)  Reimplement the config file parser from scratch.
71    
72    -------------------------------------------------------------------------------
73    
74    Simple Valgrind-like checks?
75            o)  Mark every address with bits which tell whether or not the address
76                has been written to.
77            o)  What should happen when programs are loaded?  Text/data, bss (zero
78                filled). But stack space and heap is uninitialized.
79            o)  Uninitialized local variables:
80                    A load from a place on the stack which has not previously
81                    been stored to => warning. Increasing the stack pointer using
82                    any available means should reset the memory to uninitialized.
83            o)  If calls to malloc() and free() can be intercepted:
84                    o)  Access to a memory area after free() => warning.
85                    o)  Memory returned by malloc() is marked as not-initialized.
86                    o)  Non-passive, but good to have: Change the argument
87                        given to malloc, to return a slightly larger memory
88                        area, i.e.  margin_before + size + margin_after,
89                        and return the pointer  + margin_before.
90                        Any access to the margin_before or _after space results
91                        in warnings. (free() must be modified to free the
92                        actually allocated address.)
93    
94    SMP:
95            o)  dev_mp doesn't work well with dyntrans yet
96            o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
97    
98    MIPS:
99            +)  Some more work on opcodes.
100                    x) The "wait" instruction. How to implement this functionality?
101                            (SMP, non-MIPS, interrupt correctness, host idling, ...)
102                    x) MIPS64 revision 2.
103                            o)  Find out which actual CPUs implement the rev2 ISA!
104                    x) _MAYBE_ TX79 and R5900 actually differ in their
105                       opcodes? Check this carefully!
106            o)  Dyntrans: Count register updates are probably not 100% correct yet.
107            o)  Refactor code for performance and readability/maintainability.
108            o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
109                a rotation bit which differs from previous ISAs.
110            o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
111                _NOT_ the same as for R5900!
112            o)  (Re)implement 128-bit loads/stores for R5900.
113            o)  R4000 and others:
114                    x)  watchhi/watchlo exceptions, and other exception
115                        handling details
116            o)  R10000 and others:  (R12000, R14000 ?)
117                    x)  memory space, exceptions, ...
118                    x)  use cop0 framemask for tlb lookups
119                        (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)
120    
121  Dyntrans:  Dyntrans:
122          TOP Priority:          x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
123                  x)  64-bit stuff: good generic virtual memory translation, and                  so that it caches a translation (that is, an instruction
124                      other structures. not all 64 bits need to be used                  word and the instr_call it was translated to the last
125                      (e.g. Alpha)                  time), so that it doesn't need to do slow
126                  x)  Delay slots!                  to_be_translated for each end of page?
127                  x)  Old MIPS -> dyntrans!          x)  Program Counter statistics:
128          Other stuff:                  Per machine? What about SMP? All data to the same file?
129                    A debugger command should be possible to use to enable/
130                    disable statistics gathering.
131                    Configuration file option!
132            x)  Common fatal_abort() function, which drops into the debugger
133                    without continuing.
134          x)  INVALIDATION should cause translations in _all_ cpus to be          x)  INVALIDATION should cause translations in _all_ cpus to be
135              invalidated, e.g. on a write to a write-protected page              invalidated, e.g. on a write to a write-protected page
136              (containing code)              (containing code)
         x)  Think about sharing code between CPUs of the same  
             arch/bitlength/endianness (the translation caches).  
             (Eg. a little-endian R4000 and a little-endian R5000 could  
             share code, but not an R3000 and an R4000.)  
         x)  better (meaningful) instr call statistics  
         x)  Call/return hints?  
137          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
         x)  PPC optimizations; instr combs  
         x)  Alpha  
         x)  SPARC  
         x)  PPC (64-bit stuff)  
138          x)  Lots of other stuff: see src/cpus/README_DYNTRANS          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
139          x)  true recompilation backend? think carefully about this,          x)  true recompilation backend? think carefully about this,
140              experiment in a separate project (not in GXemul)              experiment in a separate project (not in GXemul)
141                    o) First test would be to just implement a simple
142                       instruction such as MIPS' addiu or lui, on AMD64
143                       hosts...
144            x)  Idle loop detection? (Depends on target.) Could be turned
145                into usleep(1) or similar on the host... except when doing
146                e.g. SMP emulation. Then it becomes trickier.
147    
148    Transputer:
149            x)  Implement support for Helios binaries.
150            x)  Stack and register contents at startup?
151            x)  Figure out how to boot an entire Helios distribution.
152            x)  Implement all instructions. :)
153    
154    Alpha:
155            o)  Virtual memory (tlbs etc)
156            o)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
157    
158    SPARC:
159            o)  Load/stores to alternate address spaces!
160            o)  Save/restore register windows etc!
161            o)  Finish the subcc and addcc flag computation code.
162            o)  Add more registers (floating point, control regs etc)
163            o)  Disassemly of some more instructions?
164            o)  Are sll etc 32-bit sign-extending or zero-extending?
165            o)  Finish the GDB register stuff.
166            o)  SPARC v8, v7 etc?
167    
168    Debugger:
169            o)  How does SMP debugging work? Does it simply use "threads"?
170                    What if the guest OS (running on an emulated SMP machine)
171                    has a usertask running, with userland threads?
172            o)  Try to make the debugger more modular and, if possible, reentrant!
173            o)  Remove the emul command? (But show network info if showing
174                    machines?)
175            o)  Generalize the expression evaluator. (debugger_expr.c?)
176                    settable variables      ("show nr of instructions on average")
177                    emul[x]                 defaults to current emul
178                    machine[x]              defaults to current machine
179                    cpu[x]                  defaults to currently focused cpu
180                    registers               cpu arch dependent (#-prefix)
181                    symbols                 @-prefix
182                    numeric constants       decimal, hex, and octal ($-prefix)
183                    boolean                 yes,no, true,false
184                    operators (+ - * / % & | ^ !)
185                    parentheses for grouping subexpressions
186                    NOTE: the change from % to # for register prefix!
187                    examples:
188                                    emul[0].machine[2].cpu[0].pc
189                                    machine[test2].cpu[1].ra = main
190                                    settings.show_trace_tree = yes
191    
192                    Settings:
193                            o)  Remove a setting.
194                            o)  Read/write a setting given a name. (Read as
195                                string and/or int64_t simultaneously?)
196                            o)  Warnings when exiting the emulator, if the
197                                settings have not been removed exactly in
198                                the same way as they were added? This would
199                                improve code cleanliness in the long term.
200                                (I.e. require a corresponding _destroy()
201                                function for all _new functions... machine_
202                                cpu_ etc.)
203    
204                    Help command should have subsections! One for "expressions",
205                    mirrored in the documentation, but the internal help should
206                    be the one that should be considered correct.
207            o)  see src/debugger.c for more
208    
209    POWER/PowerPC:
210            x)  PPC optimizations; instr combs
211            x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
212                    version of AIX? (if there exists such a thing)
213            x)  find and fix the bug which causes NetBSD/macppc to fail after
214                an install!
215            x)  macppc: adb controller; keyboard (for framebuffer mode)
216            x)  make OpenBSD/macppc work (PCI controller stuff)
217    
218    Algor:
219            PCI interrupts... needed or stuff like the tlp NIC?
220    
221    ARM:
222            o)  try to get netbsd/evbarm 3.x running (iq80321)
223            o)  make the xscale counter registers (ccnt) work
224            o)  make the ata controller usable for FreeBSD!
225            o)  zaurus for openbsd...
226            o)  debian/cats crashes because of unimplemented coproc stuff.
227                fix this?
228    
229    Cache simulation:
230            o)  Command line flags for:
231                    o)  CPU endianness?
232                    o)  Cache sizes? (multiple levels)
233            o)  Separate from the CPU concept, so that multi-core CPUs sharing
234                e.g. a L2 cache can be simulated (?)
235            o)  Instruction cache emulation is easiest (if separate from the
236                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
237                NOTE: if the architecture has a delay slot, then an instruction
238                slot can actually be executed as 2 instructions.
239            o)  Data cache emulation = harder; each arch's load/store routines
240                must include support? running one instruction at a time and
241                having a cpu-dependant lookup function for each instruction
242                is another option (easier to implement, but very very slow).
243    
244    Documentation:
245            o)  machines, cpus, devices.
246            o)  Automagic documentation generation:
247                    x)  REMEMBER that several machines/devices can be in
248                            the same source file!
249            o)  Try to rewrite the install instructions for those machines
250                that use 3MAX into using CATS? (To remove the need to a raw
251                ffs partition using up all of the disk image.)
252    
253  More generic out_of_memory error reporting, and check everywhere!  More generic out_of_memory error reporting, and check everywhere!
254          Causes: OpenBSD has low default limits for normal users.          Causes: OpenBSD has low default limits for normal users.
# Line 44  Breakpoints: 32-bit vs 64-bit sign exten Line 263  Breakpoints: 32-bit vs 64-bit sign exten
263          extended soon to support stuff like  "2*x + symbol + y" etc. cool          extended soon to support stuff like  "2*x + symbol + y" etc. cool
264          stuff)          stuff)
265    
 Sprite (guest OS for DECstation emulation)  
         x)  Timing problems during bootup?  
   
266  The Device subsystem:  The Device subsystem:
267          x)  allow devices to be moved and/or changed in size (down to a          x)  allow devices to be moved and/or changed in size (down to a
268              minimum size, etc, or up to a max size)              minimum size, etc, or up to a max size)
269          x)  keep track of interrupts and busses? actually, allowing any device          x)  keep track of interrupts and busses? actually, allowing any device
270              to be a bus might be a nice idea              to be a bus might be a nice idea.
271            x)  turn interrupt controllers into devices? :-)
272          x)  refactor various clocks/nvram/cmos into one device?          x)  refactor various clocks/nvram/cmos into one device?
273    
274  ARM:  Clocks:
275          o)  add ID for "i80321 600MHz rev 2 (XScale core)"          x)  General framework for automagic clock adjustment for _all_
276          o)  make the ata controller usable for FreeBSD!              kinds of clocks and timers. (Which should be possible to turn
277          x)  zaurus for openbsd...              off, of course, like the way DECstation emulation works now.)
278    
279  PCI:  PCI:
280            x)  last write was ffffffff ==> fix this, it should be used
281                together with a mask to get the correct bits. also, not ALL
282                bits are size bits! (lowest 4 vs lowest 2?)
283          x)  add support for address fixups          x)  add support for address fixups
284          x)  generalize the interrupt routing stuff (lines etc). this should          x)  generalize the interrupt routing stuff (lines etc). this should
285              be per machine? or per bus, that's better              be per machine? or per bus, that's better
286            x)  add a "pcn" NIC (AMD PCnet32 Lance 79c970 (PCI 1022:2000)),
287  MacPPC:              could be useful for several machine modes (Malta, Algor, evbarm,
288          x)  dev_zs / interrupts?              hp700?, macppc, etc.)
         x)  adb controller; keyboard  
         x)  make OpenBSD/macppc work (PCI controller stuff)  
289    
290  Network layer:  Network layer:
291          o)  DHCP (for Debian and BSD installers :-)          o)  DHCP (for Debian and BSD installers :-)
# Line 87  Busses: Line 305  Busses:
305          o)  dev->bus: TurboChannel, PCMCIA, ADB?          o)  dev->bus: TurboChannel, PCMCIA, ADB?
306    
307  Config file parser:  Config file parser:
308          o)  Refresh/rewrite it :)          o)  Rewrite it from scratch!
309          o)  Usage of any expression available through the debugger          o)  Usage of any expression available through the debugger
         o)  Expressions such as "add device" would be nice to be able  
             to do on the command line manually.  
         o)  Allow machine() entries even if there is no emul() entry (but  
             then don't allow any emul() entries at all).  
310          o)  Support for running debugger commands (like the -c          o)  Support for running debugger commands (like the -c
311              command line option)              command line option)
312    
313  Floating point layer:  Floating point layer:
314          o)  make it common enough to be used by _all_ emulation modes          o)  make it common enough to be used by _all_ emulation modes
315            o)  implement more stuff
316          o)  non-IEEE modes (i.e. x86)?          o)  non-IEEE modes (i.e. x86)?
317    
318  Userland emulation:  Userland emulation:
# Line 108  Sound: Line 323  Sound:
323          x)  generic sound framework          x)  generic sound framework
324          x)  add one or more sound cards as devices          x)  add one or more sound cards as devices
325    
326    ASC SCSI controller:
327            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
328                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
329                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
330                2005/11/06/0024.html suggests that.)
331    
332  Caches / memory hierarchies: (this is mostly MIPS-specific)  Caches / memory hierarchies: (this is mostly MIPS-specific)
         o)  MIPS coproc.c: bits in config registers should reflect  
             correct cache sizes for _all_ CPU types. (currently only  
             implemented for R4000, R1x000, and a few others)  
333          o)  src/memory*.c: Implement correct cache emulation for          o)  src/memory*.c: Implement correct cache emulation for
334              all CPU types. (currently only R2000/R3000 is implemented)              all CPU types. (currently only R2000/R3000 is implemented)
335              (per CPU, multiple levels should be possible,              (per CPU, multiple levels should be possible, associativity etc!)
             associativity etc!)  
336          o)  R2000/R3000 isn't _100%_ correct, just almost correct :)          o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
337          o)  Move the -S (fill mem with random) functionality into the          o)  Move the -S (fill mem with random) functionality into the
338              memory.c subsystem, not machine.c or wherever it is now              memory.c subsystem, not machine.c or wherever it is now
# Line 128  Caches / memory hierarchies: (this is mo Line 345  Caches / memory hierarchies: (this is mo
345              memory latencies should be emulated as correctly as              memory latencies should be emulated as correctly as
346              possible.              possible.
347    
 MIPS CPU emulation:  (note: this is for the OLD mips stuff)  
         o)  i386 bintrans backend: movn etc, slt[u] for  
                 64-bit mode, 64-bit shifts etc  
         o)  Instructions:  
                 o)  All ISAs:  
                         o)  Floating point exception handling, and  
                                 add more instructions.  
                         o)  Finish the MIPS16 translator, and test it!  
                         o)  MIPS ISA I, II, III, IV  
                         o)  MIPS V (SIMD vector stuff?)  
                         o)  MDMX  (MIPS Digital Media Extension)  
                         o)  MIPS 3D  
                         o)  MIPS MT (Multi-thread stuff) (What's this?)  
                 o)  Warn about mis-used bit fields (ie bits that  
                     should be all zeroes, warn about if they are not)!  
                     Both for coprocessor registers and for instruction  
                     opcodes.  
                 o)  the special2 stuff is a mess right now  
                 o)  warn and/or cause exceptions for unimplemented  
                     instructions (depending on CPU type)  
         o)  R2000/R3000:  
                 x)  R3000 "tri-byte stores". (What's this?)  
         o)  R4000 and others:  
                 x)  watchhi/watchlo exceptions, and other exception  
                     handling details  
         o)  R10000 and others:  (R12000, R14000 ?)  
                 x)  memory space, exceptions, ...  
                 x)  use cop0 framemask for tlb lookups  
                     (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)  Implement load delays?  Warnings on interlocks.  
         o)  Implement all coprocessor 0 bits / functions.  
                 x)  coproc 0 selectors! (R4000 ?)  
         o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird  
                 TLB/cache? 128-bit GPRs, new instructions),  
                 4K (note: NOT R4000), 5K (note: NOT R5000),  
                 R6000 (ISA II), R8000  
         o)  Multi-cpu stuff:  
                 +)  Interrupt routing (ie devices vs mainbus, or  
                     connect each device to a fixed cpu)  
                 +)  SGI's NUMA architecture. Study  
                         x)  Linux sources  
                         x)  SGI's specs on NUMA address space  
                 +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(  
                 +)  Own experiments with ycx2.  
   
348  File/disk/symbol handling:  File/disk/symbol handling:
349            o)  Remove some of the complexity in file format guessing, for
350                    Ultrix kernels that are actually disk images?
351          o)  Better handling of tape files          o)  Better handling of tape files
352          o)  Read function argument count and types from binaries? (ELF?)          o)  Read function argument count and types from binaries? (ELF?)
353          o)  Demangle C++ names.          o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
354                Microsoft's C++, so multiple schemes must be possible. See
355  Debugger:              URL at top of src/symbol_demangle.c for more info.
         o)  see src/debugger.c for more  
356    
357  Userland ABI emulation:  Userland ABI emulation:
358          o)  see src/useremul.c          o)  see src/useremul.c
# Line 206  Better framebuffer and X-windows functio Line 379  Better framebuffer and X-windows functio
379                  on size (and center the image, with a black border).                  on size (and center the image, with a black border).
380          o)  Different scaledown on different windows?          o)  Different scaledown on different windows?
381          o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)          o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
382            o)  Bug reported by Elijah Rutschman on MacOS with weird
383                keys (F5 = cursor down?).
384          o)  Keyboard and mouse events:          o)  Keyboard and mouse events:
385                  x)  Do this for more machines than just DECstation                  x)  Do this for more machines than just DECstation
386                  x)  more X11 cursor keycodes                  x)  more X11 cursor keycodes

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