/[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 27 by dpavlin, Mon Oct 8 16:20:10 2007 UTC revision 28 by dpavlin, Mon Oct 8 16:20:26 2007 UTC
# Line 1  Line 1 
1  $Id: TODO,v 1.298 2006/06/25 11:08:04 debug Exp $  $Id: TODO,v 1.324 2006/07/22 10:23:39 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  --------------  Code cleanup:
6            x)  64-bit ranges in src/cpus/memory_mips_v2p.c
7            x)  Revert the dyntrans page template experiment? Hm.
8            x)  Refactor the cpu type detection/initialization/listing.
9    
10          x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!  Documentation:
11          x)  Find a way to get rid of the cpu_create_or_reset_tc in the          x)  Rewrite the section about experimental devices, after the
12              R2000/R3000 cache isolation code. (NetBSD works without it,              framebuffer acceleration has been implemented, and demos
13              but not Ultrix and Linux yet.)              written. (Symbolic names instead of numbers; example
14          x)  Formalize the statistics gathering stuff for dyntrans...              use cases, etc. Mention demo files that use the various
15          x)  ... and use it to optimize MIPS dyntrans stuff.              features?)
16          x)  Clock framework? Go through all clock devices, make sure they          x)  "a very simple linear framebuffer device (for graphics output)"
17                under "which machines does gxemul emulate" ==> better
18                description?
19            x)  Better description on how to set up a cross compiler?
20                Example for MIPS64.
21    
22    Long-term implementation:
23            x)  Testmachine includes:
24                    + dev_fb block fill and copy
25                    + dev_fb draw characters (from the built-in font)?
26                    + dev_fb input device? mouse pointer coordinates and buttons
27                            (allow changes in these to cause interrupts as well?)
28                    + Redefine the halt() function so that it stops "sometimes
29                      soon", i.e. usage in demo code should be:
30                            for (;;) {
31                                    halt();
32                            }
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            x)  Make the wdc controller work with modern versions of NetBSD!
36            x)  Continue on SPARC emulation
37                    + Enable it in the configure script as soon as it can
38                      run all the demo programs.
39            x)  Continue on Alpha emulation  (virtual memory, etc). Cleanup.
40            x)  Alignment exceptions (MIPS, PPC, ARM?, ...)
41    
42    Long-term design:
43            x)  Instruction combination collisions? How to avoid easily...
44            o)  Actually use the settings object, better debugger stuff, etc!
45            o)  Debugger command for enabling/disabling instruction statistics
46                during runtime.   machine.statistics = on|off
47            x)  MAINBUS REDESIGN!
48            x)  Clock framework! Go through all clock devices, make sure they
49              return correct data, and run at correct speeds!              return correct data, and run at correct speeds!
50          x)  Optimizations, continuing on 64-bit issues etc with dyntrans          x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
51                it would be reasonably simple to add; in each individual fast
52                load/store routine = a lot more work, and it would become
53                kludgy very fast.)
54          x)  Dyntrans with SMP... lots of work to be done here.          x)  Dyntrans with SMP... lots of work to be done here.
55          x)  Dyntrans with cache emulation... lots of work here as well.          x)  Dyntrans with cache emulation... lots of work here as well.
56          x)  Actually use the settings object, better debugger stuff, etc.          x)  Reimplement the config file parser from scratch.
         x)  Wait for new releases of NetBSD, and test with those.  
57    
58  --------------  Test:
59            x)  Test with more than one Sprite instance on an emulated network!
60            x)  NetBSD 4.x, once it is out.
61    
62    -------------------------------------------------------------------------------
63    
64    Simple Valgrind-like checks?
65            o)  Mark every address with bits which tell whether or not the address
66                has been written to.
67            o)  What should happen when programs are loaded?  Text/data, bss (zero
68                filled). But stack space and heap is uninitialized.
69            o)  Uninitialized local variables:
70                    A load from a place on the stack which has not previously
71                    been stored to => warning. Increasing the stack pointer using
72                    any available means should reset the memory to uninitialized.
73            o)  If calls to malloc() and free() can be intercepted:
74                    o)  Access to a memory area after free() => warning.
75                    o)  Memory returned by malloc() is marked as not-initialized.
76                    o)  Non-passive, but good to have: Change the argument
77                        given to malloc, to return a slightly larger memory
78                        area, i.e.  margin_before + size + margin_after,
79                        and return the pointer  + margin_before.
80                        Any access to the margin_before or _after space results
81                        in warnings. (free() must be modified to free the
82                        actually allocated address.)
83    
84  SMP:  SMP:
85          o)  dev_mp doesn't work well with dyntrans yet          o)  dev_mp doesn't work well with dyntrans yet
86          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
87    
88  MIPS:  MIPS:
         o)  Fix invalidate_asid so it works well for non-R3000 too!  
         x)  [Re]add an interrupt-asserted bit for MIPS, to speed up  
             interrupt handling slightly?  
         +)  Print a warning on the first reserved instruction.  
89          +)  Some more work on opcodes.          +)  Some more work on opcodes.
90                  x) MIPS64 revision 2.                  x) MIPS64 revision 2.
91                            o)  Find out which actual CPUs implement the rev2 ISA!
92                  x) _MAYBE_ TX79 and R5900 actually differ in their                  x) _MAYBE_ TX79 and R5900 actually differ in their
93                     opcodes? Check this carefully!                     opcodes? Check this carefully!
94          o)  Dyntrans: Count register updates are probably not 100% correct yet.          o)  Dyntrans: Count register updates are probably not 100% correct yet.
         o)  Dyntrans: SMP correctness  
95          o)  Refactor code for performance and readability/maintainability.          o)  Refactor code for performance and readability/maintainability.
96          o)  Instruction combinations? Possible candidates (but profile first!):          o)  Instruction combinations? Possible candidates (but profile first!):
97                  o)  multiple loads/stores in a row                  o)  R2000/R3000 cache cleaner!
98                  o)  strlen, memset loops etc                  o)  strlen, memset loops etc
99                    o)  multiple loads/stores in a row, e.g. relative to
100                        the stack pointer
101                    o)  lui + or, lui + add, and 64-bit variants
102                    o)  jr ra + addiu to the v0 register?
103                  o)  compare + branch                  o)  compare + branch
104          o)  DROTR32 and similar MIPS64 rev 2 instructions, which have          o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
105              a rotation bit which differs from previous ISAs.              a rotation bit which differs from previous ISAs.
106          o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are          o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
107              _NOT_ the same as for R5900!              _NOT_ the same as for R5900!
108            o)  (Re)implement 128-bit loads/stores for R5900.
109          o)  R4000 and others:          o)  R4000 and others:
110                  x)  watchhi/watchlo exceptions, and other exception                  x)  watchhi/watchlo exceptions, and other exception
111                      handling details                      handling details
# Line 53  MIPS: Line 115  MIPS:
115                      (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)                      (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)
116    
117  Dyntrans:  Dyntrans:
118          x)  Move the mips_init_64bit_dummy_tables() etc calls into          x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
119              src/cpu.c, for all 64-bit cpus?                  so that it caches a translation (that is, an instruction
120          x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably                  word and the instr_call it was translated to the last
121                  help performance a bit.                  time), so that it doesn't need to do slow
122                    to_be_translated for each end of page?
123            x)  Program Counter statistics:
124                    Per machine? What about SMP? All data to the same file?
125                    A debugger command should be possible to use to enable/
126                    disable statistics gathering.
127                    Configuration file option!
128          x)  Common fatal_abort() function, which drops into the debugger          x)  Common fatal_abort() function, which drops into the debugger
129                  without continuing.                  without continuing.
130          x)  INVALIDATION should cause translations in _all_ cpus to be          x)  INVALIDATION should cause translations in _all_ cpus to be
131              invalidated, e.g. on a write to a write-protected page              invalidated, e.g. on a write to a write-protected page
132              (containing code)              (containing code)
         x)  better (formally defined) instr call statistics (-s command  
             line option?), multiple different types? (virtual pc, physical pc)  
133          x)  Call/return hints?          x)  Call/return hints?
134          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
135          x)  H8?          x)  H8?
136          x)  Lots of other stuff: see src/cpus/README_DYNTRANS          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
137          x)  true recompilation backend? think carefully about this,          x)  true recompilation backend? think carefully about this,
138              experiment in a separate project (not in GXemul)              experiment in a separate project (not in GXemul)
139          x)  Remove the dyntrans_alignment_check functionality; although                  o) First test would be to just implement a simple
140              it gives slightly higher peformance sometimes, it increases                     instruction such as MIPS' addiu or lui, on AMD64
141              the complexity of the code too much!                     hosts...
142            x)  Idle loop detection? (Depends on target.) Could be turned
143                into usleep(1) or similar on the host... except when doing
144                e.g. SMP emulation. Then it becomes trickier.
145    
146  Alpha:  Alpha:
147          o)  Virtual memory (tlbs etc)          o)  Virtual memory (tlbs etc)
# Line 81  Alpha: Line 150  Alpha:
150  SPARC:  SPARC:
151          o)  Add all registers (floating point, control regs etc)          o)  Add all registers (floating point, control regs etc)
152          o)  Save/restore register windows etc!          o)  Save/restore register windows etc!
153          o)  Disassemly of some more instructions.          o)  Load/stores!
154            o)  Disassemly of some more instructions?
155          o)  Are sll etc 32-bit sign-extending or zero-extending?          o)  Are sll etc 32-bit sign-extending or zero-extending?
156          o)  Finish the cmp (subcc) flag computation code.          o)  Finish the cmp (subcc) flag computation code.
157          o)  Finish the GDB register stuff.          o)  Finish the GDB register stuff.
158            o)  SPARC v8, v7 etc?
159    
160  Debugger:  Debugger:
161          o)  How does SMP debugging work? Does it simply use "threads"?          o)  How does SMP debugging work? Does it simply use "threads"?
# Line 114  Debugger: Line 185  Debugger:
185                          o)  Remove a setting.                          o)  Remove a setting.
186                          o)  Read/write a setting given a name. (Read as                          o)  Read/write a setting given a name. (Read as
187                              string and/or int64_t simultaneously?)                              string and/or int64_t simultaneously?)
188                            o)  Warnings when exiting the emulator, if the
189                                settings have not been removed exactly in
190                                the same way as they were added? This would
191                                improve code cleanliness in the long term.
192                                (I.e. require a corresponding _destroy()
193                                function for all _new functions... machine_
194                                cpu_ etc.)
195    
196                  Help command should have subsections! One for "expressions",                  Help command should have subsections! One for "expressions",
197                  mirrored in the documentation, but the internal help should                  mirrored in the documentation, but the internal help should
# Line 122  Debugger: Line 200  Debugger:
200    
201  POWER/PowerPC:  POWER/PowerPC:
202          x)  PPC optimizations; instr combs          x)  PPC optimizations; instr combs
203          x)  64-bit stuff          x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
204                    version of AIX? (if there exists such a thing)
205          x)  find and fix the bug which causes NetBSD/macppc to fail after          x)  find and fix the bug which causes NetBSD/macppc to fail after
206              an install!              an install!
207          x)  macppc: adb controller; keyboard (for framebuffer mode)          x)  macppc: adb controller; keyboard (for framebuffer mode)
# Line 141  ARM: Line 220  ARM:
220              fix this?              fix this?
221    
222  Cache simulation:  Cache simulation:
223            o)  Command line flags for:
224                    o)  CPU endianness?
225                    o)  Cache sizes? (multiple levels)
226          o)  Separate from the CPU concept, so that multi-core CPUs sharing          o)  Separate from the CPU concept, so that multi-core CPUs sharing
227              e.g. a L2 cache can be simulated (?)              e.g. a L2 cache can be simulated (?)
228          o)  Instruction cache emulation is easiest (if separate from the          o)  Instruction cache emulation is easiest (if separate from the
# Line 174  Breakpoints: 32-bit vs 64-bit sign exten Line 256  Breakpoints: 32-bit vs 64-bit sign exten
256          extended soon to support stuff like  "2*x + symbol + y" etc. cool          extended soon to support stuff like  "2*x + symbol + y" etc. cool
257          stuff)          stuff)
258    
 Sprite (guest OS for DECstation emulation)  
         x)  Timing problems during bootup?  
   
259  The Device subsystem:  The Device subsystem:
260          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
261              minimum size, etc, or up to a max size)              minimum size, etc, or up to a max size)
# Line 244  ASC SCSI controller: Line 323  ASC SCSI controller:
323              2005/11/06/0024.html suggests that.)              2005/11/06/0024.html suggests that.)
324    
325  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)  
326          o)  src/memory*.c: Implement correct cache emulation for          o)  src/memory*.c: Implement correct cache emulation for
327              all CPU types. (currently only R2000/R3000 is implemented)              all CPU types. (currently only R2000/R3000 is implemented)
328              (per CPU, multiple levels should be possible,              (per CPU, multiple levels should be possible, associativity etc!)
             associativity etc!)  
329          o)  R2000/R3000 isn't _100%_ correct, just almost correct :)          o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
330          o)  Move the -S (fill mem with random) functionality into the          o)  Move the -S (fill mem with random) functionality into the
331              memory.c subsystem, not machine.c or wherever it is now              memory.c subsystem, not machine.c or wherever it is now
# Line 264  Caches / memory hierarchies: (this is mo Line 339  Caches / memory hierarchies: (this is mo
339              possible.              possible.
340    
341  File/disk/symbol handling:  File/disk/symbol handling:
342            o)  Remove some of the complexity in file format guessing, for
343                    Ultrix kernels that are actually disk images?
344          o)  Better handling of tape files          o)  Better handling of tape files
345          o)  Read function argument count and types from binaries? (ELF?)          o)  Read function argument count and types from binaries? (ELF?)
346          o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.          o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.

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