/[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 2 by dpavlin, Mon Oct 8 16:17:48 2007 UTC revision 34 by dpavlin, Mon Oct 8 16:21:17 2007 UTC
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1  $Id: TODO,v 1.125 2005/03/06 08:21:10 debug Exp $  $Id: TODO,v 1.453 2007/02/19 01:34:42 debug Exp $
2    
3  Here's a short list of what I have left to do on GXemul. This file is a mess.  -------------------------------------------------------------------------------
 Order is random. Don't trust it to be up-to-date.  
4    
5    Fix after the 0.4.4 release:
6            Fix the PowerPC DECR interrupt speed!
7    
8          Caches / memory hierarchies: (this is mostly MIPS-specific)  -------------------------------------------------------------------------------
9                  o)  MIPS coproc.c: bits in config registers should reflect  
10                      correct cache sizes for _all_ CPU types. (currently only  Possible (relatively large) work packages to concentrate on in the future:
11                      implemented for R4000, R1x000, and a few others)  
12                  o)  src/memory*.c: Implement correct cache emulation for    x)  SMP:
13                      all CPU types. (currently only R2000/R3000 is implemented)          Get SMP working again. It is pretty much broken since I started
14                      (per CPU, multiple levels should be possible,          the conversion from the old bintrans system to the new dyntrans system.
15                      associativity etc!)          Add better Test machine demos for SMP in the demos directory.
16                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)  
17                  o)  Move the -S (fill mem with random) functionality into the    x)  Network:
18                      memory.c subsystem, not machine.c or wherever it is now          Redesign of the networking subsystem, at least the NAT translation
19                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)          part. The current way of allowing raw ethernet frames to be
20                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          transfered to/from the emulator via UDP should probably be extended
21                      (using manual swap-out of blocks to disk, ugly)          to allow the frames to be transmitted other ways as well.
22                  o)  A global command line option should be used to turn          Also adding support for connecting ttys (either to xterms, or to
23                      cache emulation on or off. When off, caches should be          pipes/sockets etc, or even to PPP->NAT or SLIP->NAT :-).
24                      faked like they are right now. When on, caches and  
25                      memory latencies should be emulated as correctly as    x)  PCI:
26                      possible.          Pretty much everything related to runtime configuration, device
27            slots, interrupts, whatever. The current code is very hardcoded
28          Network layer:          and ugly.
29                  o)  Multiple networks per emulation, and let different  
30                      NICs in machines connect to different networks.    x)  Debugging:
31                  o)  Network across multiple hosts.          Think more about SMP debugging, etc. Right now, the
32                  o)  Fixed MAC addresses for NICs, fixed IPv4 addresses if          debugger is a mess. Also, a better connection to GDB would be
33                      DHCP or RARP is used.          very nice to have.
34                  o)  many other issues: see src/net.c  
35      x)  Userland emulation:
36          Configure script:          Primary goals would be NetBSD and Linux syscall emulation.
37                  o)  Only enable Alpha prefetch on pca56 etc, not on ev4, ev5.  
38                  o)  Use getopts?  And of course, there are _LOTS_ of minor TODOs spread out throughout
39                  o)  X11 libs and headers via command line option?  the source code, which must be fixed sooner or later.
40                  o)  Verify that the configure script, building and running  
41                      the emulator works on some platforms:  -------------------------------------------------------------------------------
42                          +)  Irix, AIX, QNX  
43                          +)  MacOS X  (I've not tried this personally yet)  Some other things, in random order, that I'd like to fix: (Some items in
44                          +)  Ultrix using gcc? (Inside the emulator)  this list are probably out-to-date by now.)
45    
46          CPU emulation:  Dyntrans:
47                  o)  Binary translation:          x)  Instruction combination collisions? How to avoid easily...
48                          +)  use an Intermediate Representation!          x)  Think about how to do both SHmedia and SHcompact in a reasonable
49                          +)  recursive translation?              way! (Or AMD64 long/protected/real, for that matter.)
50                          +)  basic blocks instead of one-instruction? :)          x)  68K emulation; think about how to do variable instruction
51                          +)  on Alpha: don't assume pca56-like byte load/store?              lengths across page boundaries.
52                          +)  write backends for UltraSparc and MIPS          x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
53                          +)  see src/bintrans.c for more info              it would be reasonably simple to add; in each individual fast
54                load/store routine = a lot more work, and it would become
55          MIPS CPU emulation:              kludgy very fast.)
56                  o)  Instructions:          x)  Dyntrans with SMP... lots of work to be done here.
57                          o)  Regression tests (see tests/README for more info):          x)  Dyntrans with cache emulation... lots of work here as well.
58                                  o)  Floating point exception handling, and          o)  dev_mp doesn't work well with dyntrans yet
59                                          add more instructions.          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
60                                  o)  Finish the MIPS16 translator, and test it!          x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
61                                  o)  MIPS ISA I, II, III, IV                  so that it caches a translation (that is, an instruction
62                                  o)  MIPS V (SIMD vector stuff?)                  word and the instr_call it was translated to the last
63                                  o)  MDMX  (MIPS Digital Media Extension)                  time), so that it doesn't need to do slow
64                                  o)  MIPS 3D                  to_be_translated for each end of page?
65                                  o)  MIPS MT (Multi-thread stuff) (What's this?)          x)  Program Counter statistics:
66                          o)  Warn about mis-used bit fields (ie bits that                  Per machine? What about SMP? All data to the same file?
67                              should be all zeroes, warn about if they are not)!                  A debugger command should be possible to use to enable/
68                              Both for coprocessor registers and for instruction                  disable statistics gathering.
69                              opcodes.                  Configuration file option!
70                          o)  the special2 stuff is a mess right now          x)  Breakpoints:
71                          o)  warn and/or cause exceptions for unimplemented                  o) Physical vs virtual addresses!
72                              instructions (depending on CPU type)                  o) 32-bit vs 64-bit sign extension for MIPS, and others?
73                  o)  R2000/R3000:          x)  INVALIDATION should cause translations in _all_ cpus to be
74                          x)  R3000 "tri-byte stores". (What's this?)              invalidated, e.g. on a write to a write-protected page
75                  o)  R4000 and others:              (containing code)
76                          x)  watchhi/watchlo exceptions, and other exception          x)  16-bit encodings? (MIPS16, ARM Thumb, 32-bit SH on SH64)
77                              handling details          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
78                  o)  R10000 and others:  (R12000, R14000 ?)          x)  true recompilation backend? think carefully about this.
79                          x)  memory space, exceptions, ...                  o)  abstract syntax for emitting opcopdes
80                          x)  use cop0 framemask for tlb lookups                  o)  convert into native code only after an entire
81                              (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)                          block has been translated? probably best.
82                  o)  Implement load delays?  Warnings on interlocks.                  o)  x86/amd64 code generator can be very similar... perhaps
83                  o)  Implement all coprocessor 0 bits / functions.                  o)  branches to already translated code blocks can
84                          x)  coproc 0 selectors! (R4000 ?)                          link the blocks together
85                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird                  o)  load/store are the most important.
86                          TLB/cache? 128-bit GPRs, new instructions),  
87                          4K (note: NOT R4000), 5K (note: NOT R5000),  Simple Valgrind-like checks?
88                          R6000 (ISA II), R8000          o)  Mark every address with bits which tell whether or not the address
89                  o)  Multi-cpu stuff:              has been written to.
90                          +)  SGI's NUMA architecture. Study          o)  What should happen when programs are loaded?  Text/data, bss (zero
91                                  x)  Linux sources              filled). But stack space and heap is uninitialized.
92                                  x)  SGI's specs on NUMA address space          o)  Uninitialized local variables:
93                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(                  A load from a place on the stack which has not previously
94                          +)  Own experiments with ycx2.                  been stored to => warning. Increasing the stack pointer using
95                    any available means should reset the memory to uninitialized.
96          Emulation of specific machines and devices:          o)  If calls to malloc() and free() can be intercepted:
97                  o)  Clean up stuff to make it possible to emulate multiple                  o)  Access to a memory area after free() => warning.
98                      (different) machines simultaneously.                  o)  Memory returned by malloc() is marked as not-initialized.
99                  o)  Use same clock for all emulations and machines.                  o)  Non-passive, but good to have: Change the argument
100                  o)  Clean up the device stuff (registering of devices etc)                      given to malloc, to return a slightly larger memory
101                  o)  Various SCSI and IDE controllers                      area, i.e.  margin_before + size + margin_after,
102                  o)  PS/2-style keyboard controller (for several machines)                      and return the pointer  + margin_before.
103                  o)  Generic busses;                      Any access to the margin_before or _after space results
104                          x)  PCI:  i/o and interrupts                      in warnings. (free() must be modified to free the
105                          x)  QBus-22 (DECsystem 5500, 5400?)                      actually allocated address.)
106                  o)  DECstations (pmax):  
107                          x)  ioasic  MIPS:
108                          x)  framebuffers:          o)  Nicer MIPS status bits in register dumps.
109                                  +)  better cursor support, overlays?,          o)  Alignment exceptions.
110                                  +)  2D/3D acceleration, PX[G]          o)  Floating point exception correctness.
111                          x)  status words / control words, make this more          o)  Fix this? Triggered by NetBSD/sgimips? Hm:
112                                  portable/cleaner                  to_be_translated(): TODO: unimplemented instruction:
113                          x)  scsi controller(s): sii, DMA for asc                  000000000065102c: 00200800 (d)  rot_00  at,zr,0
114                          x)  serial controllers: ssc, scc (and more work on dc?)          o)  Some more work on opcodes.
115                          x)  nvram on decstation 5000/125:  when using X11,                  x) MIPS64 revision 2.
116                                  set console=g or similar                          o)  Find out which actual CPUs implement the rev2 ISA!
117                          x)  DECstation 5840? "xbi-based SMP"                          o)  DROTR32 and similar MIPS64 rev 2 instructions,
118                  o)  SGI and ARC machines (sgimips, arc):                              which have a rotation bit which differs from
119                          x)  IP32 ("O2"): (Lots of stuff)                              previous ISAs.
120                                  +)  mec (ethernet)                          o)  EI and DI instructions for MIPS64/32 rev 2.
121                                  +)  pci                              NOTE: These are _NOT_ the same as for R5900!
122                                  +)  ahc (scsi)                  x) _MAYBE_ TX79 and R5900 actually differ in their
123                                  +)  ps2 kbd                     opcodes? Check this carefully!
124                                  +)  memory controller          o)  Dyntrans: Count register updates are probably not 100% correct yet.
125                                  +)  framebuffer/graphics          o)  Refactor code for performance and readability/maintainability.
126                                  +)  caches          o)  (Re)implement 128-bit loads/stores for R5900.
127                          x)  more ARCBIOS stuff          o)  R4000 and others:
128                          x)  Memory/interrupt controllers                  x)  watchhi/watchlo exceptions, and other exception
129                          x)  IP30 (Linux with graphics support?)                      handling details
130                          x)  SMP / NUMA?  (SGI and various ARC machines)          o)  R10000 and others:  (R12000, R14000 ?)
131                  o)  Cobalt:  PCI and interrupt system, ethernet,                  x)  The code before the line
132                          harddisk controller(s)                          /*  reg[COP0_PAGEMASK] = cpu->cd.mips.coproc[0]->tlbs[0].mask & PAGEMASK_MASK;  */
133                  o)  Playstation 2:                      in cpu_mips.c is not correct for R10000 according to
134                          Hardware:  OHCI usb controller, keyboard, IDE, ...                      Lemote's Godson patches for GXemul. TODO: Go through all
135                          Has an R3000A as a subsystem (!)                      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
136                  o)  hpcmips:  framebuffer(s) and harddisk controller,                      and make sure everything works with R10000.
137                          among other things                      Then test with OpenBSD/sgi?
138                  o)  newsmips:                  x)  memory space, exceptions, ...
139                          o)  NetBSD/newsmips, get it to detect a "real"                  x)  use cop0 framemask for tlb lookups
140                              model, right now everything is 100% bogus                      (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)
141                  o)  Less interesting platforms:  
142                          o)  mipsco? (NetBSD)  SuperH:
143                          o)  wgrisc? (big endian R3000, in OpenBSD's attic)          x)  SH4 interrupt controller:
144                          o)  other embedded / evaluation MIPS boards                  x)  Implement correct priorities of interrupts
145                          o)  Playstation 1? R3000A. Weird hardware?          x)  SH4 DMA (0xffa00000)
146                                  No FPU, but something as coproc 2.          x)  SH4 UBC (0xff200000)
147                          o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp          x)  Store queues can copy 32 bytes at a time, there's no need to
148                                  (R4300, 4MB RAM, really weird memory map)              copy individual 32-bit words. (Performance improvement.)
149            x)  SH4 BSC (Bus State Controller)
150          File/disk handling:          x)  SH4 RTC: Read the host's clock.
151                  o)  Read function argument count and types from binaries? (ELF?)          x)  SH4 SCIF: Serial _interrupts_
152                  o)  ELF: separate LE/BE (MIPS instruction format) from LSB/MSB          x)  Instruction tracing should include symbols for branch targets,
153                          (ELF structure format)?              and so on, to make the output more human readable.
154                  o)  Better handling of tape files          x)  NetBSD/evbsh3, dreamcast, mmeye, hpcsh! Linux?
155            x)  Replace pc-relative loads with immediate load, if within the
156          Userland ABI emulation:              same page. (Similar to the same optimization for ARM.)
157                  o)  see src/useremul.c          x)  Floating point speed!
158            x)  Floating point exception correctness.
159          Terminal based interactive debugger:          x)  Think carefully about how to implement SH5/SH64 (for evbsh5).
160                  o)  see src/debugger.c  
161    Dreamcast:
162          GDB interface? (Maybe not necessary; the built-in debugger feels          x)  G2 DMA
163          more useful.)          x)  LAN adapter (dev_mb8696x.c).  NetBSD root-on-nfs.
164            x)  PVR:  Lots of stuff. See dev_pvr.c.
165          GUI, interactive debugger?  GTK+?  (The GUI _must be optional_!)          x)  GDROM
166                  o)  Breakpoints (complex expressions? combinations of register          x)  Modem
167                          states, memory accesses and so on)          x)  PCI bridge/bus?
168                  o)  Instruction trace          x)  Maple bus:
169                  o)  Disassembly of RAM (_NOT_ the same as instruction trace)                  x)  Correct controller input
170                  o)  Function call trace                  x)  Mouse input
171                  o)  Inspection of CPU registers/state, coprocessor          x)  Software emulation of BIOS calls:
172                          registers/state, any device registers/state/contents                  x)  GD-ROM emulation: Use the GDROM device.
173                          o)  Framebuffers in windows / tabs.                  x)  Use the VGA font as a fake ROM font. (Better than
174                          o)  Contents of RAM                      nothing.)
175                  o)  "Start new emulation" should allow amount of          x)  Linux/dreamcast? (The gentoo kernel currently crashes.)
176                          RAM and nr of cpus to easily be specified.          x)  Make as many as possible of the KOS examples run!
177                          Multiple simultaneous machines should be possible.          x)  More homebrew demos/games.
178                  o)  Disk images.          x)  SPU: Sound emulation (ARM cpu).
179            x)  VME processor emulation? "(Sanyo LC8670 "Potato")" according to
180          Regression tests:              Wikipedia, LC86K87 according to Comstedt's page. See
181                  o)  see tests/              http://www.maushammer.com/vmu.html for a good description of
182                the differences between LC86104C and the one used in the VME.
183          Save state of the whole emulated machine, to be able to load it back  
184                  in later?  (Memory, all device's states, all registers and  Transputer:
185                  so on.  Like taking a snapshot. (SimOS seems to do this,          x)  Implement support for Helios binaries.
186                  according to its website.))          x)  Stack and register contents at startup?
187            x)  Figure out how to boot an entire Helios distribution.
188          Better X-windows functionality:          x)  Implement all instructions. :)
189                  o)  CLEAN UP the ugly event code  
190                  o)  Mouse clicks can be "missed" in the current system; this is  RCA1802/RCA1805, CHIP8:
191                      not good. They should be put on a stack of some kind.          x)  CHIP8 -> RCA180x conversion
192                  o)  More 2D and 3D framebuffer acceleration.                  x)  Think about how to do dual-mode, variable-instr-length
193                  o)  Non-resizable windows?  Or choose scaledown depending                      ISAs, and switch between modes.
194                          on size (and center the image, with a black border).                  x)  1805 "extended" opcode -> trigger CHIP8 emulation?
195                  o)  Different scaledown on different windows?                          That is, all calls 0NNN could point to 0x68 opcodes,
196                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)                          which, if running on a 1802 in CHIP8-emulation-mode,
197                  o)  Keyboard and mouse events:                          would be manually interpreted.
198                          x)  Do this for more machines than just DECstation                  x)  Better solution:
199                          x)  more X11 cursor keycodes                          CHIP8 calls to 00xx => handle at high level,
200                          x)  Keys like CTRL, ALT, SHIFT do not get through                                calls to 0xxx in general = call 180X machine code
201                              by themselves (these are necessary for example                                  (0000 = reboot?)
202                              to change the font of an xterm in X in the          x)  1802 info: http://www.nyx.net/~lturner/public_html/Cosmac.html
203                              emulator)              and:  http://www.elf-emulation.com/1802.html
204                  o)  Generalize the framebuffer stuff by moving _ALL_ X11          x)  1805 extended opcodes: Implement at least disassembly support!
205                          specific code to src/x11.c!          x)  Keyboard input.
206            x)  Sound (beep only).
207          Statistics:  (this could be interesting)          x)  Slow-down to correct speed? Wikipedia: "it was usually operated
208                  o)  Save to file and show graphics. It should be possible to              at 3.58 MHz/2 to suit the requirements of the 1861 chip which
209                      run gxemul after a simulation to just show the graphics,              gave a speed of a little over 100,000 instructions per second"
210                      or convert to a .ppm or .tga or similar.              (Note that _CHIP8_ emulation would then be even slower.)
211                  o)  memory accesses (to measure cache efficiency and          x)  SCHIP48 (Super) emulation:
212                          page coloring efficiency)                  Some more opcodes, 128x64 framebuffer, larger
213                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS                  sprites and fonts.
214                  o)  percentage of time spent in different "states", such as  
215                      running userland code, kernel code, or idling (for CPUs  Alpha:
216                      that have such an instruction, or whenever the PC is          x)  OSF1 PALcode, Virtual memory support.
217                      inside a specific idle-function (address range)).          x)  PALcode replacement! PAL1E etc opcodes...?
218                      Possible additional state (for example on R3000): caches          x)  Interrupt/exception/trap handling.
219                      disabled.          x)  Floating point exception correctness.
220                  o)  position of read/write on (SCSI) disks          x)  More work on bootup memory and register contents.
221            x)  More Alpha machine types, so it could work with
222                OpenBSD, FreeBSD, and Linux too?
223    
224    SPARC:
225            o)  Implement Adress space identifiers; load/stores etc.
226            o)  Save/restore register windows etc! Both v9 and pre-v9!
227            o)  Finish the subcc and addcc flag computation code.
228            o)  Add more registers (floating point, control regs etc)
229            o)  Exception/trap handling.
230            o)  Disassemly of some more instructions?
231            o)  Are sll etc 32-bit sign-extending or zero-extending?
232            o)  Finish the GDB register stuff.
233            x)  Floating point exception correctness.
234            o)  SPARC v8, v7 etc?
235    
236    Debugger:
237            o)  How does SMP debugging work? Does it simply use "threads"?
238                    What if the guest OS (running on an emulated SMP machine)
239                    has a usertask running, with userland threads?
240            o)  Try to make the debugger more modular and, if possible, reentrant!
241            o)  Remove the emul command? (But show network info if showing
242                    machines?)
243            o)  Evaluate expressions within []? That would allow stuff like
244                    cpu[x] where x is an expression.
245            o)  Settings:
246                    x)  Special handlers for Write!
247                            +)  MIPS coproc regs
248                            +)  Alpha/MIPS/SPARC zero registers
249                            +)  x86 64/32/16-bit registers
250                    x)  Value formatter for resulting output.
251            o)  see src/debugger.c for more
252    
253    POWER/PowerPC:
254            x)  Fix DECR timer speed, so it matches the host.
255            x)  NetBSD/prep 3.x triggers a possible bug in the emulator:
256                <wdc_exec_command(0xd005e514,0xd60cdd30,0,8,..)>
257                  <ata_get_xfer(0,0xd60cdd30,0,8,..)>
258                    <0x26c550(&ata_xfer_pool,2,0,8,..)>
259                    <0x35c71c(0x3f27000,0,52,8,..)>
260                  <ata_exec_xfer(0xd005e4c8,0x3f27000,0,13,..)>
261                    <atastart(0xd005e4c8,0x3f27000,0,13,..)>
262                      <__wdccommand_start(0xd005e4c8,0x3f27000,0,13,..)>
263                        <bsw1(&prep_isa_io_space_tag,0x800001f6,0,176,..)>
264                    [ wdc: write to SDH: 0xb0 (sectorsize 2, lba=1, drive 1, head 0) ]
265                        <wdcwait(0xd005e4c8,72,64,0xbb8,..)>
266                          <0x198120(0xd005e4c8,72,64,0xbb8,..)>
267                            <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
268                            <delay(100,0,0,0xbb8,..)>
269                Note: <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
270            x)  PPC optimizations; instr combs
271            x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
272                    version of AIX? (if there exists such a thing)
273            x)  macppc: adb controller; keyboard (for framebuffer mode)
274            x)  make OpenBSD/macppc work (PCI controller stuff)
275            x)  Floating point exception correctness.
276            x)  Alignment exceptions.
277    
278    PReP:
279            Clock time! ("Bad battery blah blah")
280    
281    Algor:
282            o)  Other models than the P5064?
283            o)  PCI interrupts... needed for stuff like the tlp NIC?
284    
285    BeBox:
286            o)  Interrupts. There seems to be a problem with WDC interrupts
287                "after a short while", although a few interrupts get through?
288            o)  Perhaps find a copy of BeOS and try it?
289    
290    HPCmips:
291            x)  Mouse/pad support! :)
292            x)  A NIC? (As a PCMCIA device?)
293    
294    AVR:
295            o)  Everything.
296    
297    ARM:
298            o)  See netwinder_reset() in NetBSD; the current "an internal error
299                occured" message after reboot/halt is too ugly.
300            o)  ARM "wait"-like instruction?
301            o)  try to get netbsd/evbarm 3.x or 4.x running (iq80321)
302            o)  make the xscale counter registers (ccnt) work
303            o)  make the ata controller usable for FreeBSD!
304            o)  Zaurus emulation, for e.g. OpenBSD/zaurus
305            o)  Debian/cats crashes because of unimplemented coproc stuff.
306                fix this?
307    
308    Test machines:
309            o)  dev_fb block fill and copy
310            o)  dev_fb draw characters (from the built-in font)?
311            o)  dev_fb input device? mouse pointer coordinates and buttons
312                    (allow changes in these to cause interrupts as well?)
313            o)  Redefine the halt() function so that it stops "sometimes
314                soon", i.e. usage in demo code should be:
315                    for (;;) {
316                            halt();
317                    }
318    
319    Better CD Image file support:
320            x)  Support CD formats that contain more than 1 track, e.g.
321                CDI files (?). These can then contain a mixture of e.g. sound
322                and data tracks, and booting from an ISO filesystem path
323                would boot from [by default] the first data track.
324                (This would make sense for e.g. Dreamcast CD images, or
325                possibly other live-CD formats.)
326    
327    Networking:
328            x)  Fix performance problems caused by only allowing a
329                single TCP packet to be unacked.
330            x)  Don't hardcode offsets into packets!
331            x)  Test with lower than 100 max tcp/udp connections,
332                to make sure that reuse works!
333            x)  Make OpenBSD work better as a guest OS!
334            x)  DHCP? Debian doesn't actually send DHCP packets, even
335                    though it claims to? So it is hard to test.
336            x)  Multiple networks per emulation, and let different
337                NICs in machines connect to different networks.
338            x)  Support VDE (vde.sf.net)? Easiest/cleanest (before a
339                redesign of the network framework has been done) is
340                probably to connect it using the current (udp) solution.
341            x)  Allow SLIP connections, possibly PPP, in addition to
342                ethernet?
343    
344    Cache simulation:
345            o)  Command line flags for:
346                    o)  CPU endianness?
347                    o)  Cache sizes? (multiple levels)
348            o)  Separate from the CPU concept, so that multi-core CPUs sharing
349                e.g. a L2 cache can be simulated (?)
350            o)  Instruction cache emulation is easiest (if separate from the
351                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
352                NOTE: if the architecture has a delay slot, then an instruction
353                slot can actually be executed as 2 instructions.
354            o)  Data cache emulation = harder; each arch's load/store routines
355                must include support? running one instruction at a time and
356                having a cpu-dependant lookup function for each instruction
357                is another option (easier to implement, but very very slow).
358    
359    Documentation:
360            x)  Note about sandboxing/security:
361                    Not all emulated instructions fail in the way they would
362                    do on real hardware (e.g. a userspace program writing to
363                    a system register might work in GXemul, but it would
364                    fail on real hardware).  Sandbox = contain from the
365                    host OS. But the emulated programs will run "less
366                    securely".
367            x)  Try NetBSD/arc 4.x! (It seems to work with disk images!)
368            x)  NetBSD/pmax 4 install instructions: xterm instead of vt100!
369            x)  BETTER DEVICE EXAMPLES!
370                    o)  Move away from technical.html to somewhere new.
371                    o)  DEVICE_TICK
372                    o)  Implement example devices using interrupts, dyntrans
373                        memory access, etc.?
374            x)  Document the dyntrans core?
375            x)  Rewrite the section about experimental devices, after the
376                framebuffer acceleration has been implemented, and demos
377                written. (Symbolic names instead of numbers; example
378                use cases, etc. Mention demo files that use the various
379                features?)
380            x)  "a very simple linear framebuffer device (for graphics output)"
381                under "which machines does gxemul emulate" ==> better
382                description?
383            x)  Better description on how to set up a cross compiler?
384                Example for MIPS64.
385            o)  Automagic documentation generation?
386                    x)  machines, cpus, devices.
387                    x)  REMEMBER that several machines/devices can be in
388                            the same source file!
389            o)  Try to rewrite the install instructions for those machines
390                that use 3MAX into using CATS or hpcmips? (To remove the need
391                to use a raw ffs partition, using up all of the disk image.)
392    
393    More generic out_of_memory error reporting, and check everywhere!
394            Causes: OpenBSD has low default limits for normal users.
395                    Host is 32-bit? (32-bit hosts are limited to 4 GB or less
396                    of userspace memory.)
397                    You are actually low on RAM. (As trivial as this might sound,
398                    Unix systems usually allow processes to allocate virtual
399                    memory beyond the amount of RAM in the machine.)
400    
401    The Device subsystem:
402            x)  allow devices to be moved and/or changed in size (down to a
403                minimum size, etc, or up to a max size); if there is a collision,
404                return false. It is up to the caller to handle this situation!
405            x)  NOTE: Translations must be invalidated, both for
406                registering new devices, and for moving existing ones.
407                cpu->invalidate translation caches, for all CPUs that
408                are connected to a specific memory.
409            x)  keep track of interrupts and busses? actually, allowing any device
410                to be a bus might be a nice idea.
411            x)  turn interrupt controllers into devices? :-)
412            x)  refactor various clocks/nvram/cmos into one device?
413    
414    PCI:
415            x)  last write was ffffffff ==> fix this, it should be used
416                together with a mask to get the correct bits. also, not ALL
417                bits are size bits! (lowest 4 vs lowest 2?)
418            x)  add support for address fixups
419            x)  generalize the interrupt routing stuff (lines etc)
420    
421    Clocks and timers:
422            x)  DON'T HARDCODE 100 HZ IN cpu_mips_coproc.c!
423            x)  Test the 8253? Right now it doesn't seem to be used?
424            x)  NetWinder timeofday is incorrect!
425            x)  Cobalt TOD is incorrect!
426            x)  Go through all other machines, one by one, and fix them.
427    
428    Config file parser:
429            o)  Rewrite it from scratch!
430            o)  Usage of any expression available through the debugger
431            o)  Allow interrupt controllers to be added! and interrupts
432                to be used in more ways than before
433            o)  Support for running debugger commands (like the -c
434                command line option)
435    
436    Floating point layer:
437            o)  make it common enough to be used by _all_ emulation modes
438            o)  implement correct error/exception handling and rounding modes
439            o)  implement more helper functions (i.e. add, sub, mul...)
440            o)  non-IEEE modes (i.e. x86)?
441    
442    Userland emulation:
443            x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
444            x)  Dynamic linking? Hm.
445    
446    Sound:
447            x)  generic sound framework
448            x)  add one or more sound cards as devices; add a testmachine
449                sound card first?
450            x)  Dreamcast sound? Generic PCI sound cards?
451    
452    ASC SCSI controller:
453            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
454                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
455                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
456                2005/11/06/0024.html suggests that.)
457                NetBSD 4.x seems to work? :)
458    
459    Caches / memory hierarchies: (this is mostly MIPS-specific)
460            o)  src/memory*.c: Implement correct cache emulation for
461                all CPU types. (currently only R2000/R3000 is implemented)
462                (per CPU, multiple levels should be possible, associativity etc!)
463            o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
464            o)  Move the -S (fill mem with random) functionality into the
465                memory.c subsystem, not machine.c or wherever it is now
466            o)  ECC stuff, simulation of memory errors?  (Machine dependent)
467            o)  More than 4GB of emulated RAM, when run on a 32-bit host?
468                (using manual swap-out of blocks to disk, ugly)
469            o)  A global command line option should be used to turn
470                cache emulation on or off. When off, caches should be
471                faked like they are right now. When on, caches and
472                memory latencies should be emulated as correctly as
473                possible.
474    
475    File/disk/symbol handling:
476            o)  Make sure that disks can be added/removed during runtime!
477                (Perhaps this needs a reasonably large re-write.)
478            o)  Remove some of the complexity in file format guessing, for
479                    Ultrix kernels that are actually disk images?
480            o)  Better handling of tape files      
481            o)  Read function argument count and types from binaries? (ELF?)
482            o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
483                Microsoft's C++, so multiple schemes must be possible. See
484                URL at top of src/symbol_demangle.c for more info.
485    
486    Userland ABI emulation:
487            o)  see src/useremul.c
488    
489    Better framebuffer and X-windows functionality:
490            o)  Generalize the update_x1y1x2y2 stuff to an extend-region()
491                function...
492            o)  -Yx sometimes causes crashes.
493            o)  Simple device access to framebuffer_blockcopyfill() etc,
494                and text output (using the built-in fonts), for dev_fb.
495            o)  CLEAN UP the ugly event code
496            o)  Mouse clicks can be "missed" in the current system; this is
497                not good. They should be put on a stack of some kind.
498            o)  More 2D and 3D framebuffer acceleration.
499            o)  Non-resizable windows?  Or choose scaledown depending
500                    on size (and center the image, with a black border).
501            o)  Different scaledown on different windows?
502            o)  Non-integral scale-up? (E.g. 640x480 -> 1024x768)
503            o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
504            o)  Bug reported by Elijah Rutschman on MacOS with weird
505                keys (F5 = cursor down?).
506            o)  Keyboard and mouse events:
507                    x)  Do this for more machines than just DECstation
508                    x)  more X11 cursor keycodes
509                    x)  Keys like CTRL, ALT, SHIFT do not get through
510                        by themselves (these are necessary for example
511                        to change the font of an xterm in X in the
512                        emulator)
513            o)  Generalize the framebuffer stuff by moving _ALL_ X11
514                    specific code to src/x11.c!
515    

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