/[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 12 by dpavlin, Mon Oct 8 16:18:38 2007 UTC revision 36 by dpavlin, Mon Oct 8 16:21:34 2007 UTC
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1  $Id: TODO,v 1.166 2005/08/16 05:44:33 debug Exp $  $Id: TODO,v 1.464 2007/03/16 14:13:59 debug Exp $
2    
3  ===============================================================================  -------------------------------------------------------------------------------
4    
5  High priority stuff:  Landisk SH4:
6            HITTA OCH FIXA SH4-STABILITETSPROBLEMEN!
7            SH4 RTC, läs värdmaskinens klocka.
8  MIPS bintrans:          När NetBSD 4.0 och OpenBSD 4.1 kommit ut, uppdatera
9          x)  call/return address cache?          installationsinstruktionerna i dokumentationen, flytta upp till
10            supportat OS (guestos & index).
11  dyntrans:          Lägg till landisk i emulated machines i intro.html.
12          x)  memory write protection for ARM, but NOT for Alpha (because          Sätt machine_landisk stable = 1, om/när allt funkar.
13                  it has the IMB instruction... hm)  
14    Add a special function to the testmachine devices, console perhaps?
15          x)  call/return address cache  which prints a zero-terminated string like "[[ %s ]]\n" when given
16    a virtual memory address (or a physical? or perhaps both should be possible).
17          x)  instr_call sequence analysis support? (Useful for          o) NOT to the console, but to the emulator's controlling terminal.
18                  handtuning combinations.)             DEBUG output, not console output!
19            o) Very useful for debugging. DOCUMENT it!
20          x)  opcode statistics support?  
21                  TODO: is instr_call statistics enough?  Fix the PowerPC DECR interrupt speed! (MacPPC and PReP speed, etc.)
22    
23          x)  support for archs that allow transparent unaligned load/stores  Prova att installera GNU Linux/DECstation _UTAN_
24    slow_serial_interrupts_hack_for_linux! Det kanske funkar med
25          x)  SMP: detect when an instruction such as ll/sc or cas is used,  nya interruptsystemet?
26              and "synchronize" approximately the number of executed instructions  
27              (or cycles) across all CPUs.  -------------------------------------------------------------------------------
28    
29          x)  support for variable-length instructions (x86, m68k, ...)  Possible (relatively large) work packages to concentrate on in the future:
30                  Perhaps:  don't increase the next_ic between every  
31                  instruction, but let each instruction's handler do    x)  SMP:
32                  that for itself.          Get SMP working again. It is pretty much broken since I started
33                  Problem: what about instructions crossing a (virtual)          the conversion from the old bintrans system to the new dyntrans system.
34                          page boundary? They cannot be translated once          Add better Test machine demos for SMP in the demos directory.
35                          and for all :( and must be interpreted slowly!          Either multiple dev_mp (one per cpu), or the single dev_mp must
36            _really_ keep all per-cpu values separate.
37          x)  support for THUMB or MIPS16  (arm, mips)  
38      x)  Alpha and SPARC emulation:
39          x)  support for Delay slots!  (mips, sparc, hppa)          These are the next two CPU/machine families that I want to emulate.
40    
41          x)  Alpha: hahaha, zapnot and inserts/extracts don't    x)  Network:
42              compile into very nice code :-|  fix this          Redesign of the networking subsystem, at least the NAT translation
43            part. The current way of allowing raw ethernet frames to be
44          x)  64-bit virtual memory translation tables (PPC, etc)          transfered to/from the emulator via UDP should probably be extended
45            to allow the frames to be transmitted other ways as well.
46          x)  x86: convert to dyntrans. LOTS of stuff to consider.          Also adding support for connecting ttys (either to xterms, or to
47            pipes/sockets etc, or even to PPP->NAT or SLIP->NAT :-).
48            Documentation updates (!) are very important, making it easier to
49  ===============================================================================          use the (already existing) network emulation features.
50    
51  Lower priority, but still important:    x)  PCI:
52            Pretty much everything related to runtime configuration, device
53          Redesign the entire "mainbus" concept:          slots, interrupts, whatever. The current code is very hardcoded
54                  o)  Easily configurable interrupt routing in SMP systems.          and ugly.
55                  o)  Specific clock/bus speeds, cpu speeds etc.          o) Allow cards to be added/removed during runtime more easily.
56                  o)  Synchronization over network?          o) Allow cards to be enabled/disabled (i/o ports, etc, like
57               NetBSD needs for disk controller detection).
58          Caches / memory hierarchies: (this is mostly MIPS-specific)          o) Allow devices to be moved in memory during runtime.
59                  o)  MIPS coproc.c: bits in config registers should reflect          o) Interrupts per PCI slot, etc. (A-D).
60                      correct cache sizes for _all_ CPU types. (currently only          o) PCI interrupt controller logic... very hard to get right,
61                      implemented for R4000, R1x000, and a few others)             because these differ a lot from one machine to the next.
62                  o)  src/memory*.c: Implement correct cache emulation for  
63                      all CPU types. (currently only R2000/R3000 is implemented)    x)  Debugging:
64                      (per CPU, multiple levels should be possible,          Think more about SMP debugging, etc. Right now, the
65                      associativity etc!)          debugger is a mess. Also, a better connection to GDB would be
66                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)          very nice to have.
67                  o)  Move the -S (fill mem with random) functionality into the  
68                      memory.c subsystem, not machine.c or wherever it is now    x)  Userland emulation:
69                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)          Primary goals would be NetBSD and Linux syscall emulation.
70                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?  
71                      (using manual swap-out of blocks to disk, ugly)    x)  Variable-length ISA support:
72                  o)  A global command line option should be used to turn          The support for emulation of variable length ISAs (such as
73                      cache emulation on or off. When off, caches should be          M68K, AMD64/i386, or AVR32) is not really there yet. It would
74                      faked like they are right now. When on, caches and          be very fun to work on this, to get it right.
75                      memory latencies should be emulated as correctly as  
76                      possible.    x)  Native code generation backends.
77            Not necessary to have the emulator working, but speed is
78          Network layer:          always nice to have.
79                  o)  Multiple networks per emulation, and let different  
80                      NICs in machines connect to different networks.    x)  Remove all "addr mult" device support!
81                  o)  many other issues: see src/net.c          Long term goal. Replace the current hacks with address
82            multiplication _per device_ with layered devices, so that the
83          MIPS CPU emulation:          end device (wdc, ns16550, whatever) only supports one access
84                  o)  i386 bintrans backend: movn etc, slt[u] for          style, and the layers in between convert to 16/32/64-bit
85                          64-bit mode, 64-bit shifts etc          word alignment.
86                  o)  Instructions:  
87                          o)  All ISAs:  And of course, there are _LOTS_ of minor TODOs spread out throughout
88                                  o)  Floating point exception handling, and  the source code, which must be fixed sooner or later.
89                                          add more instructions.  
90                                  o)  Finish the MIPS16 translator, and test it!  -------------------------------------------------------------------------------
91                                  o)  MIPS ISA I, II, III, IV  
92                                  o)  MIPS V (SIMD vector stuff?)  Some other things, in random order, that I'd like to fix: (Some items in
93                                  o)  MDMX  (MIPS Digital Media Extension)  this list are probably out-to-date by now.)
94                                  o)  MIPS 3D  
95                                  o)  MIPS MT (Multi-thread stuff) (What's this?)  Dyntrans:
96                          o)  Warn about mis-used bit fields (ie bits that          x)  Instruction combination collisions? How to avoid easily...
97                              should be all zeroes, warn about if they are not)!          x)  Think about how to do both SHmedia and SHcompact in a reasonable
98                              Both for coprocessor registers and for instruction              way! (Or AMD64 long/protected/real, for that matter.)
99                              opcodes.          x)  68K emulation; think about how to do variable instruction
100                          o)  the special2 stuff is a mess right now              lengths across page boundaries.
101                          o)  warn and/or cause exceptions for unimplemented          x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
102                              instructions (depending on CPU type)              it would be reasonably simple to add; in each individual fast
103                  o)  R2000/R3000:              load/store routine = a lot more work, and it would become
104                          x)  R3000 "tri-byte stores". (What's this?)              kludgy very fast.)
105                  o)  R4000 and others:          x)  Dyntrans with SMP... lots of work to be done here.
106                          x)  watchhi/watchlo exceptions, and other exception          x)  Dyntrans with cache emulation... lots of work here as well.
107                              handling details          x)  Remove the concept of base RAM completely; it would be more
108                  o)  R10000 and others:  (R12000, R14000 ?)              generic to allow RAM devices to be used "anywhere".
109                          x)  memory space, exceptions, ...          o)  dev_mp doesn't work well with dyntrans yet
110                          x)  use cop0 framemask for tlb lookups          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
111                              (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)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
112                  o)  Implement load delays?  Warnings on interlocks.                  so that it caches a translation (that is, an instruction
113                  o)  Implement all coprocessor 0 bits / functions.                  word and the instr_call it was translated to the last
114                          x)  coproc 0 selectors! (R4000 ?)                  time), so that it doesn't need to do slow
115                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird                  to_be_translated for each end of page?
116                          TLB/cache? 128-bit GPRs, new instructions),          x)  Program Counter statistics:
117                          4K (note: NOT R4000), 5K (note: NOT R5000),                  Per machine? What about SMP? All data to the same file?
118                          R6000 (ISA II), R8000                  A debugger command should be possible to use to enable/
119                  o)  Multi-cpu stuff:                  disable statistics gathering.
120                          +)  Interrupt routing (ie devices vs mainbus, or                  Configuration file option!
121                              connect each device to a fixed cpu)          x)  Breakpoints:
122                          +)  SGI's NUMA architecture. Study                  o) Physical vs virtual addresses!
123                                  x)  Linux sources                  o) 32-bit vs 64-bit sign extension for MIPS, and others?
124                                  x)  SGI's specs on NUMA address space          x)  INVALIDATION should cause translations in _all_ cpus to be
125                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(              invalidated, e.g. on a write to a write-protected page
126                          +)  Own experiments with ycx2.              (containing code)
127            x)  16-bit encodings? (MIPS16, ARM Thumb, 32-bit SH on SH64)
128          File/disk handling:          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
129                  o)  Better handling of tape files          x)  true recompilation backend? think carefully about this.
130                    o)  abstract syntax for emitting opcopdes
131          Debugger:                  o)  convert into native code only after an entire
132                  o)  Read function argument count and types from binaries? (ELF?)                          block has been translated? probably best.
133                  o)  Demangle C++ names.                  o)  x86/amd64 code generator can be very similar... perhaps
134                    o)  branches to already translated code blocks can
135          Userland ABI emulation:                          link the blocks together
136                  o)  see src/useremul.c                  o)  load/store are the most important.
137    
138          Terminal based interactive debugger:  Simple Valgrind-like checks?
139                  o)  see src/debugger.c          o)  Mark every address with bits which tell whether or not the address
140                has been written to.
141          Terminal/console stuff:          o)  What should happen when programs are loaded?  Text/data, bss (zero
142                  o)  allow emulated serial ports to be connected to the outside              filled). But stack space and heap is uninitialized.
143                      world in a more generic way, or even to other emulated          o)  Uninitialized local variables:
144                      machines(!)                  A load from a place on the stack which has not previously
145                    been stored to => warning. Increasing the stack pointer using
146          Regression tests.  (Needs to be totally rewritten, the old framework                  any available means should reset the memory to uninitialized.
147                  was removed because it was useless.)          o)  If calls to malloc() and free() can be intercepted:
148                    o)  Access to a memory area after free() => warning.
149          Save state of the whole emulated machine, to be able to load it back                  o)  Memory returned by malloc() is marked as not-initialized.
150                  in later?  (Memory, all device's states, all registers and                  o)  Non-passive, but good to have: Change the argument
151                  so on.  Like taking a snapshot. (SimOS seems to do this,                      given to malloc, to return a slightly larger memory
152                  according to its website.))                      area, i.e.  margin_before + size + margin_after,
153                        and return the pointer  + margin_before.
154          Better X-windows functionality:                      Any access to the margin_before or _after space results
155                  o)  CLEAN UP the ugly event code                      in warnings. (free() must be modified to free the
156                  o)  Mouse clicks can be "missed" in the current system; this is                      actually allocated address.)
157                      not good. They should be put on a stack of some kind.  
158                  o)  More 2D and 3D framebuffer acceleration.  MIPS:
159                  o)  Non-resizable windows?  Or choose scaledown depending          o)  Nicer MIPS status bits in register dumps.
160                          on size (and center the image, with a black border).          o)  Alignment exceptions.
161                  o)  Different scaledown on different windows?          o)  Floating point exception correctness.
162                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)          o)  Fix this? Triggered by NetBSD/sgimips? Hm:
163                  o)  Keyboard and mouse events:                  to_be_translated(): TODO: unimplemented instruction:
164                          x)  Do this for more machines than just DECstation                  000000000065102c: 00200800 (d)  rot_00  at,zr,0
165                          x)  more X11 cursor keycodes          o)  Some more work on opcodes.
166                          x)  Keys like CTRL, ALT, SHIFT do not get through                  x) MIPS64 revision 2.
167                              by themselves (these are necessary for example                          o)  Find out which actual CPUs implement the rev2 ISA!
168                              to change the font of an xterm in X in the                          o)  DROTR32 and similar MIPS64 rev 2 instructions,
169                              emulator)                              which have a rotation bit which differs from
170                  o)  Generalize the framebuffer stuff by moving _ALL_ X11                              previous ISAs.
171                          specific code to src/x11.c!                          o)  EI and DI instructions for MIPS64/32 rev 2.
172                                NOTE: These are _NOT_ the same as for R5900!
173          Statistics:  (this could be interesting)                  x) _MAYBE_ TX79 and R5900 actually differ in their
174                  o)  Save to file and show graphics. It should be possible to                     opcodes? Check this carefully!
175                      run gxemul after a simulation to just show the graphics,          o)  Dyntrans: Count register updates are probably not 100% correct yet.
176                      or convert to a .ppm or .tga or similar.          o)  Refactor code for performance and readability/maintainability.
177                  o)  memory accesses (to measure cache efficiency and          o)  (Re)implement 128-bit loads/stores for R5900.
178                          page coloring efficiency)          o)  R4000 and others:
179                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS                  x)  watchhi/watchlo exceptions, and other exception
180                  o)  percentage of time spent in different "states", such as                      handling details
181                      running userland code, kernel code, or idling (for CPUs          o)  R10000 and others:  (R12000, R14000 ?)
182                      that have such an instruction, or whenever the PC is                  x)  The code before the line
183                      inside a specific idle-function (address range)).                          /*  reg[COP0_PAGEMASK] = cpu->cd.mips.coproc[0]->tlbs[0].mask & PAGEMASK_MASK;  */
184                      Possible additional state (for example on R3000): caches                      in cpu_mips.c is not correct for R10000 according to
185                      disabled.                      Lemote's Godson patches for GXemul. TODO: Go through all
186                  o)  position of read/write on (SCSI) disks                      register definitions according to http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/hdwr/bks/SGI_Developer/books/R10K_UM/sgi_html/t5.Ver.2.0.book_263.html#HEADING334
187                        and make sure everything works with R10000.
188                        Then test with OpenBSD/sgi?
189                    x)  Entry LO mask (as above).
190                    x)  memory space, exceptions, ...
191                    x)  use cop0 framemask for tlb lookups
192                        (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)
193    
194    SuperH:
195            x)  SH4 interrupt controller:
196                    x)  Implement correct priorities of interrupts
197            x)  SH4 DMA (0xffa00000)
198            x)  SH4 UBC (0xff200000)
199            x)  Store queues can copy 32 bytes at a time, there's no need to
200                copy individual 32-bit words. (Performance improvement.)
201            x)  SH4 BSC (Bus State Controller)
202            x)  SH4 RTC: Read the host's clock.
203            x)  Instruction tracing should include symbols for branch targets,
204                and so on, to make the output more human readable.
205            x)  NetBSD/evbsh3, dreamcast, mmeye, hpcsh! Linux?
206            x)  Replace pc-relative loads with immediate load, if within the
207                same page. (Similar to the same optimization for ARM.)
208            x)  Floating point speed!
209            x)  Floating point exception correctness.
210            x)  Think carefully about how to implement SH5/SH64 (for evbsh5).
211    
212    Dreamcast:
213            x)  G2 DMA
214            x)  LAN adapter (dev_mb8696x.c).  NetBSD root-on-nfs.
215            x)  PVR:  Lots of stuff. See dev_pvr.c.
216            x)  GDROM
217            x)  Modem
218            x)  PCI bridge/bus?
219            x)  Maple bus:
220                    x)  Correct controller input
221                    x)  Mouse input
222            x)  Software emulation of BIOS calls:
223                    x)  GD-ROM emulation: Use the GDROM device.
224                    x)  Use the VGA font as a fake ROM font. (Better than
225                        nothing.)
226            x)  Linux/dreamcast? (The gentoo kernel currently crashes.)
227            x)  Make as many as possible of the KOS examples run!
228            x)  More homebrew demos/games.
229            x)  SPU: Sound emulation (ARM cpu).
230            x)  VME processor emulation? "(Sanyo LC8670 "Potato")" according to
231                Wikipedia, LC86K87 according to Comstedt's page. See
232                http://www.maushammer.com/vmu.html for a good description of
233                the differences between LC86104C and the one used in the VME.
234    
235    Transputer:
236            x)  Implement support for Helios binaries.
237            x)  Stack and register contents at startup?
238            x)  Figure out how to boot an entire Helios distribution.
239            x)  Implement all instructions. :)
240    
241    RCA1802/RCA1805, CHIP8:
242            x)  CHIP8 -> RCA180x conversion
243                    x)  Think about how to do dual-mode, variable-instr-length
244                        ISAs, and switch between modes.
245                    x)  1805 "extended" opcode -> trigger CHIP8 emulation?
246                            That is, all calls 0NNN could point to 0x68 opcodes,
247                            which, if running on a 1802 in CHIP8-emulation-mode,
248                            would be manually interpreted.
249                    x)  Better solution:
250                            CHIP8 calls to 00xx => handle at high level,
251                                  calls to 0xxx in general = call 180X machine code
252                                    (0000 = reboot?)
253            x)  1802 info: http://www.nyx.net/~lturner/public_html/Cosmac.html
254                and:  http://www.elf-emulation.com/1802.html
255            x)  1805 extended opcodes: Implement at least disassembly support!
256            x)  Keyboard input.
257            x)  Sound (beep only).
258            x)  Slow-down to correct speed? Wikipedia: "it was usually operated
259                at 3.58 MHz/2 to suit the requirements of the 1861 chip which
260                gave a speed of a little over 100,000 instructions per second"
261                (Note that _CHIP8_ emulation would then be even slower.)
262            x)  SCHIP48 (Super) emulation:
263                    Some more opcodes, 128x64 framebuffer, larger
264                    sprites and fonts.
265    
266    Alpha:
267            x)  OSF1 PALcode, Virtual memory support.
268            x)  PALcode replacement! PAL1E etc opcodes...?
269            x)  Interrupt/exception/trap handling.
270            x)  Floating point exception correctness.
271            x)  More work on bootup memory and register contents.
272            x)  More Alpha machine types, so it could work with
273                OpenBSD, FreeBSD, and Linux too?
274    
275    SPARC:
276            o)  Implement Adress space identifiers; load/stores etc.
277            o)  Save/restore register windows etc! Both v9 and pre-v9!
278            o)  Finish the subcc and addcc flag computation code.
279            o)  Add more registers (floating point, control regs etc)
280            o)  Exception/trap handling.
281            o)  Disassemly of some more instructions?
282            o)  Are sll etc 32-bit sign-extending or zero-extending?
283            o)  Finish the GDB register stuff.
284            x)  Floating point exception correctness.
285            o)  SPARC v8, v7 etc?
286    
287    Debugger:
288            o)  How does SMP debugging work? Does it simply use "threads"?
289                    What if the guest OS (running on an emulated SMP machine)
290                    has a usertask running, with userland threads?
291            o)  Try to make the debugger more modular and, if possible, reentrant!
292            o)  Remove the emul command? (But show network info if showing
293                    machines?)
294            o)  Evaluate expressions within []? That would allow stuff like
295                    cpu[x] where x is an expression.
296            o)  Settings:
297                    x)  Special handlers for Write!
298                            +)  MIPS coproc regs
299                            +)  Alpha/MIPS/SPARC zero registers
300                            +)  x86 64/32/16-bit registers
301                    x)  Value formatter for resulting output.
302            o)  see src/debugger.c for more
303    
304    POWER/PowerPC:
305            x)  Fix DECR timer speed, so it matches the host.
306            x)  NetBSD/prep 3.x triggers a possible bug in the emulator:
307                <wdc_exec_command(0xd005e514,0xd60cdd30,0,8,..)>
308                  <ata_get_xfer(0,0xd60cdd30,0,8,..)>
309                    <0x26c550(&ata_xfer_pool,2,0,8,..)>
310                    <0x35c71c(0x3f27000,0,52,8,..)>
311                  <ata_exec_xfer(0xd005e4c8,0x3f27000,0,13,..)>
312                    <atastart(0xd005e4c8,0x3f27000,0,13,..)>
313                      <__wdccommand_start(0xd005e4c8,0x3f27000,0,13,..)>
314                        <bsw1(&prep_isa_io_space_tag,0x800001f6,0,176,..)>
315                    [ wdc: write to SDH: 0xb0 (sectorsize 2, lba=1, drive 1, head 0) ]
316                        <wdcwait(0xd005e4c8,72,64,0xbb8,..)>
317                          <0x198120(0xd005e4c8,72,64,0xbb8,..)>
318                            <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
319                            <delay(100,0,0,0xbb8,..)>
320                Note: <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
321            x)  PPC optimizations; instr combs
322            x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
323                    version of AIX? (if there exists such a thing)
324            x)  macppc: adb controller; keyboard (for framebuffer mode)
325            x)  make OpenBSD/macppc work (PCI controller stuff)
326            x)  Floating point exception correctness.
327            x)  Alignment exceptions.
328    
329    PReP:
330            Clock time! ("Bad battery blah blah")
331    
332    Algor:
333            o)  Other models than the P5064?
334            o)  PCI interrupts... needed for stuff like the tlp NIC?
335    
336    BeBox:
337            o)  Interrupts. There seems to be a problem with WDC interrupts
338                "after a short while", although a few interrupts get through?
339            o)  Perhaps find a copy of BeOS and try it?
340    
341    HPCmips:
342            x)  Mouse/pad support! :)
343            x)  A NIC? (As a PCMCIA device?)
344    
345    AVR:
346            o)  Everything.
347    
348    ARM:
349            o)  See netwinder_reset() in NetBSD; the current "an internal error
350                occured" message after reboot/halt is too ugly.
351            o)  ARM "wait"-like instruction?
352            o)  try to get netbsd/evbarm 3.x or 4.x running (iq80321)
353            o)  make the xscale counter registers (ccnt) work
354            o)  make the ata controller usable for FreeBSD!
355            o)  Zaurus emulation:
356                    x)  OpenBSD/zaurus
357                    x)  NetBSD/zaurus? See the following URL:
358                        http://mail-index.netbsd.org/port-arm/2006/11/19/0000.html
359            o)  Debian/cats crashes because of unimplemented coproc stuff.
360                fix this?
361    
362    Test machines:
363            o)  dev_fb block fill and copy
364            o)  dev_fb draw characters (from the built-in font)?
365            o)  dev_fb input device? mouse pointer coordinates and buttons
366                    (allow changes in these to cause interrupts as well?)
367            o)  Redefine the halt() function so that it stops "sometimes
368                soon", i.e. usage in demo code should be:
369                    for (;;) {
370                            halt();
371                    }
372    
373    Better CD Image file support:
374            x)  Support CD formats that contain more than 1 track, e.g.
375                CDI files (?). These can then contain a mixture of e.g. sound
376                and data tracks, and booting from an ISO filesystem path
377                would boot from [by default] the first data track.
378                (This would make sense for e.g. Dreamcast CD images, or
379                possibly other live-CD formats.)
380    
381    Networking:
382            x)  Fix performance problems caused by only allowing a
383                single TCP packet to be unacked.
384            x)  Don't hardcode offsets into packets!
385            x)  Test with lower than 100 max tcp/udp connections,
386                to make sure that reuse works!
387            x)  Make OpenBSD work better as a guest OS!
388            x)  DHCP? Debian doesn't actually send DHCP packets, even
389                    though it claims to? So it is hard to test.
390            x)  Multiple networks per emulation, and let different
391                NICs in machines connect to different networks.
392            x)  Support VDE (vde.sf.net)? Easiest/cleanest (before a
393                redesign of the network framework has been done) is
394                probably to connect it using the current (udp) solution.
395            x)  Allow SLIP connections, possibly PPP, in addition to
396                ethernet?
397    
398    Cache simulation:
399            o)  Command line flags for:
400                    o)  CPU endianness?
401                    o)  Cache sizes? (multiple levels)
402            o)  Separate from the CPU concept, so that multi-core CPUs sharing
403                e.g. a L2 cache can be simulated (?)
404            o)  Instruction cache emulation is easiest (if separate from the
405                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
406                NOTE: if the architecture has a delay slot, then an instruction
407                slot can actually be executed as 2 instructions.
408            o)  Data cache emulation = harder; each arch's load/store routines
409                must include support? running one instruction at a time and
410                having a cpu-dependant lookup function for each instruction
411                is another option (easier to implement, but very very slow).
412    
413    Documentation:
414            x)  Note about sandboxing/security:
415                    Not all emulated instructions fail in the way they would
416                    do on real hardware (e.g. a userspace program writing to
417                    a system register might work in GXemul, but it would
418                    fail on real hardware).  Sandbox = contain from the
419                    host OS. But the emulated programs will run "less
420                    securely".
421            x)  Try NetBSD/arc 4.x! (It seems to work with disk images!)
422            x)  NetBSD/pmax 4 install instructions: xterm instead of vt100!
423            x)  BETTER DEVICE EXAMPLES!
424                    o)  Move away from technical.html to somewhere new.
425                    o)  DEVICE_TICK
426                    o)  Implement example devices using interrupts, dyntrans
427                        memory access, etc.?
428            x)  Document the dyntrans core?
429            x)  Rewrite the section about experimental devices, after the
430                framebuffer acceleration has been implemented, and demos
431                written. (Symbolic names instead of numbers; example
432                use cases, etc. Mention demo files that use the various
433                features?)
434            x)  "a very simple linear framebuffer device (for graphics output)"
435                under "which machines does gxemul emulate" ==> better
436                description?
437            x)  Better description on how to set up a cross compiler?
438                Example for MIPS64.
439            o)  Automagic documentation generation?
440                    x)  machines, cpus, devices.
441                    x)  REMEMBER that several machines/devices can be in
442                            the same source file!
443            o)  Try to rewrite the install instructions for those machines
444                that use 3MAX into using CATS or hpcmips? (To remove the need
445                to use a raw ffs partition, using up all of the disk image.)
446    
447    More generic out_of_memory error reporting, and check everywhere!
448            Causes: OpenBSD has low default limits for normal users.
449                    Host is 32-bit? (32-bit hosts are limited to 4 GB or less
450                    of userspace memory.)
451                    You are actually low on RAM. (As trivial as this might sound,
452                    Unix systems usually allow processes to allocate virtual
453                    memory beyond the amount of RAM in the machine.)
454    
455    The Device subsystem:
456            x)  allow devices to be moved and/or changed in size (down to a
457                minimum size, etc, or up to a max size); if there is a collision,
458                return false. It is up to the caller to handle this situation!
459            x)  NOTE: Translations must be invalidated, both for
460                registering new devices, and for moving existing ones.
461                cpu->invalidate translation caches, for all CPUs that
462                are connected to a specific memory.
463            x)  keep track of interrupts and busses? actually, allowing any device
464                to be a bus might be a nice idea.
465            x)  turn interrupt controllers into devices? :-)
466            x)  refactor various clocks/nvram/cmos into one device?
467    
468    PCI:
469            x)  last write was ffffffff ==> fix this, it should be used
470                together with a mask to get the correct bits. also, not ALL
471                bits are size bits! (lowest 4 vs lowest 2?)
472            x)  add support for address fixups
473            x)  generalize the interrupt routing stuff (lines etc)
474    
475    Clocks and timers:
476            x)  DON'T HARDCODE 100 HZ IN cpu_mips_coproc.c!
477            x)  Test the 8253? Right now it doesn't seem to be used?
478            x)  NetWinder timeofday is incorrect!
479            x)  Cobalt TOD is incorrect!
480            x)  Go through all other machines, one by one, and fix them.
481    
482    Config file parser:
483            o)  Rewrite it from scratch!
484            o)  Usage of any expression available through the debugger
485            o)  Allow interrupt controllers to be added! and interrupts
486                to be used in more ways than before
487            o)  Support for running debugger commands (like the -c
488                command line option)
489    
490    Floating point layer:
491            o)  make it common enough to be used by _all_ emulation modes
492            o)  implement correct error/exception handling and rounding modes
493            o)  implement more helper functions (i.e. add, sub, mul...)
494            o)  non-IEEE modes (i.e. x86)?
495    
496    Userland emulation:
497            x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
498            x)  Dynamic linking? Hm.
499    
500    Sound:
501            x)  generic sound framework
502            x)  add one or more sound cards as devices; add a testmachine
503                sound card first?
504            x)  Dreamcast sound? Generic PCI sound cards?
505    
506    ASC SCSI controller:
507            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
508                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
509                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
510                2005/11/06/0024.html suggests that.)
511                NetBSD 4.x seems to work? :)
512    
513    Caches / memory hierarchies: (this is mostly MIPS-specific)
514            o)  src/memory*.c: Implement correct cache emulation for
515                all CPU types. (currently only R2000/R3000 is implemented)
516                (per CPU, multiple levels should be possible, associativity etc!)
517            o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
518            o)  Move the -S (fill mem with random) functionality into the
519                memory.c subsystem, not machine.c or wherever it is now
520            o)  ECC stuff, simulation of memory errors?  (Machine dependent)
521            o)  More than 4GB of emulated RAM, when run on a 32-bit host?
522                (using manual swap-out of blocks to disk, ugly)
523            o)  A global command line option should be used to turn
524                cache emulation on or off. When off, caches should be
525                faked like they are right now. When on, caches and
526                memory latencies should be emulated as correctly as
527                possible.
528    
529    File/disk/symbol handling:
530            o)  Make sure that disks can be added/removed during runtime!
531                (Perhaps this needs a reasonably large re-write.)
532            o)  Remove some of the complexity in file format guessing, for
533                    Ultrix kernels that are actually disk images?
534            o)  Better handling of tape files      
535            o)  Read function argument count and types from binaries? (ELF?)
536            o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
537                Microsoft's C++, so multiple schemes must be possible. See
538                URL at top of src/symbol_demangle.c for more info.
539    
540    Userland ABI emulation:
541            o)  see src/useremul.c
542    
543    Better framebuffer and X-windows functionality:
544            o)  Generalize the update_x1y1x2y2 stuff to an extend-region()
545                function...
546            o)  -Yx sometimes causes crashes.
547            o)  Simple device access to framebuffer_blockcopyfill() etc,
548                and text output (using the built-in fonts), for dev_fb.
549            o)  CLEAN UP the ugly event code
550            o)  Mouse clicks can be "missed" in the current system; this is
551                not good. They should be put on a stack of some kind.
552            o)  More 2D and 3D framebuffer acceleration.
553            o)  Non-resizable windows?  Or choose scaledown depending
554                    on size (and center the image, with a black border).
555            o)  Different scaledown on different windows?
556            o)  Non-integral scale-up? (E.g. 640x480 -> 1024x768)
557            o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
558            o)  Bug reported by Elijah Rutschman on MacOS with weird
559                keys (F5 = cursor down?).
560            o)  Keyboard and mouse events:
561                    x)  Do this for more machines than just DECstation
562                    x)  more X11 cursor keycodes
563                    x)  Keys like CTRL, ALT, SHIFT do not get through
564                        by themselves (these are necessary for example
565                        to change the font of an xterm in X in the
566                        emulator)
567            o)  Generalize the framebuffer stuff by moving _ALL_ X11
568                    specific code to src/x11.c!
569    

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