/[gxemul]/trunk/TODO

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-revision 24 by dpavlin,
Mon Oct  8 16:19:56 2007 UTC
+revision 30 by dpavlin,
Mon Oct  8 16:20:40 2007 UTC
 Line 1
- $Id: TODO,v 1.292 2006/06/23 09:13:34 debug Exp $
+ $Id: TODO,v 1.343 2006/08/14 18:46:30 debug Exp $
  Hm. This file is in random order, and not all parts of it are up-to-date.
- --------------
- Possible release schedule:
+ Implementation:
+         x)  ARM "wait"-like instruction.
+         x)  CLOCK FRAMEWORK!
+         x)  Mouse support for NetBSD/pmax 4.x!
+         x)  See netwinder_reset() in NetBSD; the current "an internal error
+             occured" message after reboot/halt is too ugly.
+         x)  64-bit ranges in src/cpus/memory_mips_v2p.c
+         x)  Revert the dyntrans page template experiment? Hm.
+         x)  Refactor the cpu type detection/initialization/listing.
+                 Macro, which can be used as long as the cpu definitions
+                 contain a 'name'?
+         x)  Testmachine includes:
+                 + dev_fb block fill and copy
+                 + dev_fb draw characters (from the built-in font)?
+                 + dev_fb input device? mouse pointer coordinates and buttons
+                         (allow changes in these to cause interrupts as well?)
+                 + Redefine the halt() function so that it stops "sometimes
+                   soon", i.e. usage in demo code should be:
+                         for (;;) {
+                                 halt();
+                         }
+         x)  Continue on SPARC emulation
+                 + Enable it in the configure script as soon as it can
+                   run all the demo programs.
+         x)  Continue on Alpha emulation  (virtual memory, etc). Cleanup.
+         x)  Nicer MIPS status bits in register dumps.
+         x)  Alignment exceptions (MIPS, PPC, ARM?, ...)
+         x)  Rewrite the networking stack; make OpenBSD work better as a guest
+             OS, fix the performance problems, make Linux work with DHCP, etc.
+             Support VDE (vde.sf.net)? Allow SLIP connections, possibly PPP,
+             in addition to ethernet?
+         x)  Implement more ethernet NICs.
+         x)  IOP (I2O) device?
-.4.0:
+ Documentation:
-         x)  Quick release, even though performance for non-R3000 MIPS dyntrans
+         x)  "Install netbsd/pmax first" => only use the install kernel?
-             is really poor. (Assuming everything mentioned in the documentation
+         x)  Rewrite the section about experimental devices, after the
-             works as expected.)
+             framebuffer acceleration has been implemented, and demos
+             written. (Symbolic names instead of numbers; example
-.4.1:
+             use cases, etc. Mention demo files that use the various
-         x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
+             features?)
-         x)  Fix the interrupt problems with Ultrix!
+         x)  "a very simple linear framebuffer device (for graphics output)"
-         x)  Find/fix bug which is triggered when building the emulator inside
+             under "which machines does gxemul emulate" ==> better
-             NetBSD/pmax 3.0 inside the emulator!
+             description?
+         x)  Better description on how to set up a cross compiler?
-.4.2 ...?
+             Example for MIPS64.
-         x)  Clean-up!
-         x)  Clock framework? Go through all clock devices, make sure they
+ Long-term design:
+         x)  Instruction combination collisions? How to avoid easily...
+         x)  Think about how to do both SHmedia and SHcompact in a reasonable
+             way!
+         o)  Actually use the settings object, better debugger stuff, etc!
+         o)  Debugger command for enabling/disabling instruction statistics
+             during runtime.   machine.statistics = on|off
+         x)  MAINBUS REDESIGN!
+         x)  PCI redesign... I need to read up on how PCI actually works :)
+         x)  Clock framework! Go through all clock devices, make sure they
              return correct data, and run at correct speeds!
-         x)  Optimizations, continuing on 64-bit issues etc with dyntrans
+         x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
+             it would be reasonably simple to add; in each individual fast
+             load/store routine = a lot more work, and it would become
+             kludgy very fast.)
          x)  Dyntrans with SMP... lots of work to be done here.
          x)  Dyntrans with cache emulation... lots of work here as well.
-         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.
+ -------------------------------------------------------------------------------
- --------------
+ Simple Valgrind-like checks?
+         o)  Mark every address with bits which tell whether or not the address
+             has been written to.
+         o)  What should happen when programs are loaded?  Text/data, bss (zero
+             filled). But stack space and heap is uninitialized.
+         o)  Uninitialized local variables:
+                 A load from a place on the stack which has not previously
+                 been stored to => warning. Increasing the stack pointer using
+                 any available means should reset the memory to uninitialized.
+         o)  If calls to malloc() and free() can be intercepted:
+                 o)  Access to a memory area after free() => warning.
+                 o)  Memory returned by malloc() is marked as not-initialized.
+                 o)  Non-passive, but good to have: Change the argument
+                     given to malloc, to return a slightly larger memory
+                     area, i.e.  margin_before + size + margin_after,
+                     and return the pointer  + margin_before.
+                     Any access to the margin_before or _after space results
+                     in warnings. (free() must be modified to free the
+                     actually allocated address.)
  SMP:
          o)  dev_mp doesn't work well with dyntrans yet
          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
  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.
          +)  Some more work on opcodes.
+                 x) The "wait" instruction. How to implement this functionality?
+                         (SMP, non-MIPS, interrupt correctness, host idling, ...)
                  x) MIPS64 revision 2.
+                         o)  Find out which actual CPUs implement the rev2 ISA!
                  x) _MAYBE_ TX79 and R5900 actually differ in their
                     opcodes? Check this carefully!
          o)  Dyntrans: Count register updates are probably not 100% correct yet.
-         o)  Dyntrans: SMP correctness
          o)  Refactor code for performance and readability/maintainability.
-         o)  Instruction combinations? Possible candidates (but profile first!):
-                 o)  multiple loads/stores in a row
-                 o)  strlen, memset loops etc
-                 o)  compare + branch
          o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
              a rotation bit which differs from previous ISAs.
          o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
              _NOT_ the same as for R5900!
+         o)  (Re)implement 128-bit loads/stores for R5900.
          o)  R4000 and others:
                  x)  watchhi/watchlo exceptions, and other exception
                      handling details
-Line 62 
 MIPS:
+Line 119 
 MIPS:
                      (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)
  Dyntrans:
-         x)  Move the mips_init_64bit_dummy_tables() etc calls into
+         x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
-             src/cpu.c, for all 64-bit cpus?
+                 so that it caches a translation (that is, an instruction
-         x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably
+                 word and the instr_call it was translated to the last
-                 help performance a bit.
+                 time), so that it doesn't need to do slow
+                 to_be_translated for each end of page?
+         x)  Program Counter statistics:
+                 Per machine? What about SMP? All data to the same file?
+                 A debugger command should be possible to use to enable/
+                 disable statistics gathering.
+                 Configuration file option!
          x)  Common fatal_abort() function, which drops into the debugger
                  without continuing.
          x)  INVALIDATION should cause translations in _all_ cpus to be
              invalidated, e.g. on a write to a write-protected page
              (containing code)
-         x)  better (formally defined) instr call statistics (-s command
-             line option?), multiple different types? (virtual pc, physical pc)
-         x)  Call/return hints?
          x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
-         x)  H8?
          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
          x)  true recompilation backend? think carefully about this,
              experiment in a separate project (not in GXemul)
-         x)  Remove the dyntrans_alignment_check functionality; although
+                 o) First test would be to just implement a simple
-             it gives slightly higher peformance sometimes, it increases
+                    instruction such as MIPS' addiu or lui, on AMD64
-             the complexity of the code too much!
+                    hosts...
+         x)  Idle loop detection? (Depends on target.) Could be turned
+             into usleep(1) or similar on the host... except when doing
+             e.g. SMP emulation. Then it becomes trickier.
+ Transputer:
+         x)  Implement support for Helios binaries.
+         x)  Stack and register contents at startup?
+         x)  Figure out how to boot an entire Helios distribution.
+         x)  Implement all instructions. :)
  Alpha:
          o)  Virtual memory (tlbs etc)
          o)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
  SPARC:
-         o)  Add all registers (floating point, control regs etc)
+         o)  Load/stores to alternate address spaces!
          o)  Save/restore register windows etc!
-         o)  Disassemly of some more instructions.
+         o)  Finish the subcc and addcc flag computation code.
+         o)  Add more registers (floating point, control regs etc)
+         o)  Disassemly of some more instructions?
          o)  Are sll etc 32-bit sign-extending or zero-extending?
-         o)  Finish the cmp (subcc) flag computation code.
          o)  Finish the GDB register stuff.
+         o)  SPARC v8, v7 etc?
  Debugger:
          o)  How does SMP debugging work? Does it simply use "threads"?
-Line 123 
 Debugger:
+Line 193 
 Debugger:
                          o)  Remove a setting.
                          o)  Read/write a setting given a name. (Read as
                              string and/or int64_t simultaneously?)
+                         o)  Warnings when exiting the emulator, if the
+                             settings have not been removed exactly in
+                             the same way as they were added? This would
+                             improve code cleanliness in the long term.
+                             (I.e. require a corresponding _destroy()
+                             function for all _new functions... machine_
+                             cpu_ etc.)
                  Help command should have subsections! One for "expressions",
                  mirrored in the documentation, but the internal help should
-Line 131 
 Debugger:
+Line 208 
 Debugger:
  POWER/PowerPC:
          x)  PPC optimizations; instr combs
-         x)  64-bit stuff
+         x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
+                 version of AIX? (if there exists such a thing)
          x)  find and fix the bug which causes NetBSD/macppc to fail after
              an install!
          x)  macppc: adb controller; keyboard (for framebuffer mode)
          x)  make OpenBSD/macppc work (PCI controller stuff)
  Algor:
-         PCI and ISA and LOCAL interrupts! --> wdc could start working
+         PCI interrupts... needed or stuff like the tlp NIC?
-         Add interrupt controller in dev_algor.c.
  ARM:
          o)  try to get netbsd/evbarm 3.x running (iq80321)
-Line 150 
 ARM:
+Line 227 
 ARM:
              fix this?
  Cache simulation:
+         o)  Command line flags for:
+                 o)  CPU endianness?
+                 o)  Cache sizes? (multiple levels)
          o)  Separate from the CPU concept, so that multi-core CPUs sharing
              e.g. a L2 cache can be simulated (?)
          o)  Instruction cache emulation is easiest (if separate from the
-Line 183 
 Breakpoints: 32-bit vs 64-bit sign exten
+Line 263 
 Breakpoints: 32-bit vs 64-bit sign exten
          extended soon to support stuff like  "2*x + symbol + y" etc. cool
          stuff)
- Sprite (guest OS for DECstation emulation)
-         x)  Timing problems during bootup?
  The Device subsystem:
          x)  allow devices to be moved and/or changed in size (down to a
              minimum size, etc, or up to a max size)
-Line 253 
 ASC SCSI controller:
+Line 330 
 ASC SCSI controller:
 /11/06/0024.html suggests that.)
  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)
          o)  src/memory*.c: Implement correct cache emulation for
              all CPU types. (currently only R2000/R3000 is implemented)
-             (per CPU, multiple levels should be possible,
+             (per CPU, multiple levels should be possible, associativity etc!)
-             associativity etc!)
          o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
          o)  Move the -S (fill mem with random) functionality into the
              memory.c subsystem, not machine.c or wherever it is now
-Line 273 
 Caches / memory hierarchies: (this is mo
+Line 346 
 Caches / memory hierarchies: (this is mo
              possible.
  File/disk/symbol handling:
+         o)  Remove some of the complexity in file format guessing, for
+                 Ultrix kernels that are actually disk images?
          o)  Better handling of tape files
          o)  Read function argument count and types from binaries? (ELF?)
          o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.

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