/[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 10 by dpavlin, Mon Oct 8 16:18:27 2007 UTC revision 32 by dpavlin, Mon Oct 8 16:20:58 2007 UTC
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1  $Id: TODO,v 1.139 2005/06/23 06:55:43 debug Exp $  $Id: TODO,v 1.410 2006/11/06 05:32:38 debug Exp $
2    
3  Here's a short list of what I have left to do on GXemul. This file is a mess.  This file is my list of things I want to work on in the future. It is in
4  Order is random. Don't trust it to be up-to-date.  random order, and some parts of it are probably out-to-date by now.
5    
6          Caches / memory hierarchies: (this is mostly MIPS-specific)  
7                  o)  MIPS coproc.c: bits in config registers should reflect  Dyntrans:
8                      correct cache sizes for _all_ CPU types. (currently only          x)  Instruction combination collisions? How to avoid easily...
9                      implemented for R4000, R1x000, and a few others)          x)  Think about how to do both SHmedia and SHcompact in a reasonable
10                  o)  src/memory*.c: Implement correct cache emulation for              way! (Or AMD64 long/protected/real, for that matter.)
11                      all CPU types. (currently only R2000/R3000 is implemented)          x)  68K emulation; think about how to do variable instruction
12                      (per CPU, multiple levels should be possible,              lengths across page boundaries.
13                      associativity etc!)          x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
14                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)              it would be reasonably simple to add; in each individual fast
15                  o)  Move the -S (fill mem with random) functionality into the              load/store routine = a lot more work, and it would become
16                      memory.c subsystem, not machine.c or wherever it is now              kludgy very fast.)
17                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)          x)  Dyntrans with SMP... lots of work to be done here.
18                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          x)  Dyntrans with cache emulation... lots of work here as well.
19                      (using manual swap-out of blocks to disk, ugly)          o)  dev_mp doesn't work well with dyntrans yet
20                  o)  A global command line option should be used to turn          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
21                      cache emulation on or off. When off, caches should be          x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
22                      faked like they are right now. When on, caches and                  so that it caches a translation (that is, an instruction
23                      memory latencies should be emulated as correctly as                  word and the instr_call it was translated to the last
24                      possible.                  time), so that it doesn't need to do slow
25                    to_be_translated for each end of page?
26          Network layer:          x)  Program Counter statistics:
27                  o)  Multiple networks per emulation, and let different                  Per machine? What about SMP? All data to the same file?
28                      NICs in machines connect to different networks.                  A debugger command should be possible to use to enable/
29                  o)  many other issues: see src/net.c                  disable statistics gathering.
30                    Configuration file option!
31          CPU emulation:          x)  Breakpoints:
32                  o)  Binary translation:                  o) Physical vs virtual addresses!
33                          +)  use an Intermediate Representation!                  o) 32-bit vs 64-bit sign extension for MIPS, and others?
34                          +)  recursive translation?          x)  INVALIDATION should cause translations in _all_ cpus to be
35                          +)  basic blocks instead of one-instruction? :)              invalidated, e.g. on a write to a write-protected page
36                          +)  on Alpha: don't assume pca56-like byte load/store?              (containing code)
37                          +)  write backends for UltraSparc and MIPS          x)  16-bit encodings? (MIPS16, ARM Thumb, 32-bit SH on SH64)
38                          +)  see src/bintrans.c for more info          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
39                  o)  Dynamic-but-not-binary translation?          x)  true recompilation backend? think carefully about this,
40                  o)  All the non-MIPS modes need a bit of work.              experiment in a separate project (not in GXemul)
41                    o) First test would be to just implement a simple
42          MIPS CPU emulation:                     instruction such as MIPS' addiu or lui, on AMD64
43                  o)  Instructions:                     hosts...
44                          o)  Regression tests (see tests/README for more info):  
45                                  o)  Floating point exception handling, and  Simple Valgrind-like checks?
46                                          add more instructions.          o)  Mark every address with bits which tell whether or not the address
47                                  o)  Finish the MIPS16 translator, and test it!              has been written to.
48                                  o)  MIPS ISA I, II, III, IV          o)  What should happen when programs are loaded?  Text/data, bss (zero
49                                  o)  MIPS V (SIMD vector stuff?)              filled). But stack space and heap is uninitialized.
50                                  o)  MDMX  (MIPS Digital Media Extension)          o)  Uninitialized local variables:
51                                  o)  MIPS 3D                  A load from a place on the stack which has not previously
52                                  o)  MIPS MT (Multi-thread stuff) (What's this?)                  been stored to => warning. Increasing the stack pointer using
53                          o)  Warn about mis-used bit fields (ie bits that                  any available means should reset the memory to uninitialized.
54                              should be all zeroes, warn about if they are not)!          o)  If calls to malloc() and free() can be intercepted:
55                              Both for coprocessor registers and for instruction                  o)  Access to a memory area after free() => warning.
56                              opcodes.                  o)  Memory returned by malloc() is marked as not-initialized.
57                          o)  the special2 stuff is a mess right now                  o)  Non-passive, but good to have: Change the argument
58                          o)  warn and/or cause exceptions for unimplemented                      given to malloc, to return a slightly larger memory
59                              instructions (depending on CPU type)                      area, i.e.  margin_before + size + margin_after,
60                  o)  R2000/R3000:                      and return the pointer  + margin_before.
61                          x)  R3000 "tri-byte stores". (What's this?)                      Any access to the margin_before or _after space results
62                  o)  R4000 and others:                      in warnings. (free() must be modified to free the
63                          x)  watchhi/watchlo exceptions, and other exception                      actually allocated address.)
64                              handling details  
65                  o)  R10000 and others:  (R12000, R14000 ?)  MIPS:
66                          x)  memory space, exceptions, ...          o)  Nicer MIPS status bits in register dumps.
67                          x)  use cop0 framemask for tlb lookups          o)  Alignment exceptions.
68                              (http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/hdwr/bks/SGI_Developer/books/R10K_UM/sgi_html/t5.Ver.2.0.book_284.html)          o)  Floating point exception correctness.
69                  o)  Implement load delays?  Warnings on interlocks.          o)  Fix this? Triggered by NetBSD/sgimips? Hm:
70                  o)  Implement all coprocessor 0 bits / functions.                  to_be_translated(): TODO: unimplemented instruction:
71                          x)  coproc 0 selectors! (R4000 ?)                  000000000065102c: 00200800 (d)  rot_00  at,zr,0
72                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird          o)  Some more work on opcodes.
73                          TLB/cache? 128-bit GPRs, new instructions),                  x) MIPS64 revision 2.
74                          4K (note: NOT R4000), 5K (note: NOT R5000),                          o)  Find out which actual CPUs implement the rev2 ISA!
75                          R6000 (ISA II), R8000                          o)  DROTR32 and similar MIPS64 rev 2 instructions,
76                  o)  Multi-cpu stuff:                              which have a rotation bit which differs from
77                          +)  SGI's NUMA architecture. Study                              previous ISAs.
78                                  x)  Linux sources                          o)  EI and DI instructions for MIPS64/32 rev 2.
79                                  x)  SGI's specs on NUMA address space                              NOTE: These are _NOT_ the same as for R5900!
80                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(                  x) _MAYBE_ TX79 and R5900 actually differ in their
81                          +)  Own experiments with ycx2.                     opcodes? Check this carefully!
82            o)  Dyntrans: Count register updates are probably not 100% correct yet.
83          Emulation of specific machines and devices:          o)  Refactor code for performance and readability/maintainability.
84                  o)  Use same clock for all emulations and machines.          o)  (Re)implement 128-bit loads/stores for R5900.
85                  o)  Clean up the device stuff (registering of devices etc)          o)  R4000 and others:
86                  o)  Various SCSI and IDE controllers                  x)  watchhi/watchlo exceptions, and other exception
87                  o)  PS/2-style keyboard controller (for several machines)                      handling details
88                  o)  Generic busses;          o)  R10000 and others:  (R12000, R14000 ?)
89                          x)  PCI:  i/o and interrupts                  x)  memory space, exceptions, ...
90                          x)  QBus-22 (DECsystem 5500, 5400?)                  x)  use cop0 framemask for tlb lookups
91                  o)  DECstations (pmax):                      (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)
92                          x)  ioasic  
93                          x)  framebuffers:  SuperH:
94                                  +)  better cursor support, overlays?,          x)  DMA (0xffa00000)
95                                  +)  2D/3D acceleration, PX[G]          x)  Instruction tracing should include symbols for branch targets,
96                          x)  status words / control words, make this more              and so on...
97                                  portable/cleaner          x)  SH4 interrupt controller:
98                          x)  scsi controller(s): sii, DMA for asc                  x)  Implement correct priorities of interrupts
99                          x)  serial controllers: ssc, scc (and more work on dc?)          x)  SH4 BSC (Bus State Controller)
100                          x)  nvram on decstation 5000/125:  when using X11,          x)  NetBSD/evbsh3, dreamcast, mmeye, hpcsh! Linux?
101                                  set console=g or similar          x)  Replace pc-relative loads with immediate load, if within the
102                          x)  DECstation 5840? "xbi-based SMP"              same page. (Similar to the same optimization for ARM.)
103                  o)  SGI and ARC machines (sgimips, arc):          x)  Floating point exception correctness.
104                          x)  IP32 ("O2"): (Lots of stuff)          x)  Floating point speed!
105                                  +)  mec (ethernet)          x)  Think carefully about how to implement SH5/SH64 (for evbsh5).
106                                  +)  pci  
107                                  +)  ahc (scsi)  Dreamcast:
108                                  +)  ps2 kbd          x)  CD image bootup:
109                                  +)  memory controller                  0)  Find IP.BIN, and load it to 0x8c008000.
110                                  +)  framebuffer/graphics                  1)  Run code at 0x8c008300 (SEGA license code).
111                                  +)  caches                  2)  When the license code runs a "boot menu" syscall,
112                          x)  more ARCBIOS stuff                      load the 1ST_READ.BIN file (unscrambled?) to 0x8c010000.
113                          x)  Memory/interrupt controllers                  3)  Run code at 0x8c00b800 (Bootstrap 1). This will in turn
114                          x)  IP30 (Linux with graphics support?)                      jump to 0x8c00e000 (Bootstrap 2), and then jump to
115                          x)  SMP / NUMA?  (SGI and various ARC machines)                      0x8c010000, to start the program.
116                  o)  Playstation 2:                  (Try with e.g. Comstedt's Serial IP Slave, to make sure it
117                          Hardware:  OHCI usb controller, keyboard, ...                  works as expected.)
118                  o)  Less interesting platforms:          x)  LAN adapter.
119                          o)  newsmips:          x)  PVR:  Lots of stuff. See dev_pvr.c.
120                                  o)  NetBSD/newsmips, get it to detect a "real"          x)  Maple bus:
121                                      model, right now everything is 100% bogus                  x)  Correct controller input
122                          o)  mipsco? (NetBSD)                  x)  Mouse input
123                          o)  wgrisc? (big endian R3000, in OpenBSD's attic)          x)  PROM/BIOS calls:
124                          o)  other embedded / evaluation MIPS boards                  x)  GD-ROM emulation
125                          o)  Playstation 1? R3000A. Weird hardware?          x)  NetBSD/dreamcast: Root on nfs?
126                                  No FPU, but something as coproc 2.          x)  Linux/dreamcast? (The gentoo kernel currently crashes.)
127                          o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp          x)  More homebrew demos/games.
128                                  (R4300, 4MB RAM, really weird memory map)          x)  Sound emulation (ARM cpu).
129            x)  VME processor emulation?
130          File/disk handling:  
131                  o)  Read function argument count and types from binaries? (ELF?)  Transputer:
132                  o)  Better handling of tape files          x)  Implement support for Helios binaries.
133            x)  Stack and register contents at startup?
134          Userland ABI emulation:          x)  Figure out how to boot an entire Helios distribution.
135                  o)  see src/useremul.c          x)  Implement all instructions. :)
136    
137          Terminal based interactive debugger:  RCA1802/RCA1805, CHIP8:
138                  o)  see src/debugger.c          x)  CHIP8 -> RCA180x conversion
139                    x)  Think about how to do dual-mode, variable-instr-length
140          Terminal/console stuff:                      ISAs, and switch between modes.
141                  o)  allow emulated serial ports to be connected to the outside                  x)  1805 "extended" opcode -> trigger CHIP8 emulation?
142                      world in a more generic way, or even to other emulated                          That is, all calls 0NNN could point to 0x68 opcodes,
143                      machines(!)                          which, if running on a 1802 in CHIP8-emulation-mode,
144                            would be manually interpreted.
145          Regression tests:  (Should be totally rewritten.)                  x)  Better solution:
146                  o)  see tests/                          CHIP8 calls to 00xx => handle at high level,
147                                  calls to 0xxx in general = call 180X machine code
148          Save state of the whole emulated machine, to be able to load it back                                  (0000 = reboot?)
149                  in later?  (Memory, all device's states, all registers and          x)  1802 info: http://www.nyx.net/~lturner/public_html/Cosmac.html
150                  so on.  Like taking a snapshot. (SimOS seems to do this,              and:  http://www.elf-emulation.com/1802.html
151                  according to its website.))          x)  1805 extended opcodes: Implement at least disassembly support!
152            x)  Keyboard input.
153          Better X-windows functionality:          x)  Sound (beep only).
154                  o)  CLEAN UP the ugly event code          x)  Slow-down to correct speed? Wikipedia: "it was usually operated
155                  o)  Mouse clicks can be "missed" in the current system; this is              at 3.58 MHz/2 to suit the requirements of the 1861 chip which
156                      not good. They should be put on a stack of some kind.              gave a speed of a little over 100,000 instructions per second"
157                  o)  More 2D and 3D framebuffer acceleration.              (Note that _CHIP8_ emulation would then be even slower.)
158                  o)  Non-resizable windows?  Or choose scaledown depending          x)  SCHIP48 (Super) emulation:
159                          on size (and center the image, with a black border).                  Some more opcodes, 128x64 framebuffer, larger
160                  o)  Different scaledown on different windows?                  sprites and fonts.
161                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)  
162                  o)  Keyboard and mouse events:  Alpha:
163                          x)  Do this for more machines than just DECstation          x)  OSF1 PALcode, Virtual memory support.
164                          x)  more X11 cursor keycodes          x)  PALcode replacement! PAL1E etc opcodes...?
165                          x)  Keys like CTRL, ALT, SHIFT do not get through          x)  Interrupt/exception/trap handling.
166                              by themselves (these are necessary for example          x)  Floating point exception correctness.
167                              to change the font of an xterm in X in the          x)  More work on bootup memory and register contents.
168                              emulator)          x)  More Alpha machine types, so it could work with
169                  o)  Generalize the framebuffer stuff by moving _ALL_ X11              OpenBSD, FreeBSD, and Linux too?
170                          specific code to src/x11.c!  
171    SPARC:
172          Statistics:  (this could be interesting)          o)  Implement Adress space identifiers; load/stores etc.
173                  o)  Save to file and show graphics. It should be possible to          o)  Save/restore register windows etc!
174                      run gxemul after a simulation to just show the graphics,          o)  Finish the subcc and addcc flag computation code.
175                      or convert to a .ppm or .tga or similar.          o)  Add more registers (floating point, control regs etc)
176                  o)  memory accesses (to measure cache efficiency and          o)  Exception/trap handling.
177                          page coloring efficiency)          o)  Disassemly of some more instructions?
178                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS          o)  Are sll etc 32-bit sign-extending or zero-extending?
179                  o)  percentage of time spent in different "states", such as          o)  Finish the GDB register stuff.
180                      running userland code, kernel code, or idling (for CPUs          x)  Floating point exception correctness.
181                      that have such an instruction, or whenever the PC is          o)  SPARC v8, v7 etc?
182                      inside a specific idle-function (address range)).  
183                      Possible additional state (for example on R3000): caches  Debugger:
184                      disabled.          o)  How does SMP debugging work? Does it simply use "threads"?
185                  o)  position of read/write on (SCSI) disks                  What if the guest OS (running on an emulated SMP machine)
186                    has a usertask running, with userland threads?
187            o)  Try to make the debugger more modular and, if possible, reentrant!
188            o)  Remove the emul command? (But show network info if showing
189                    machines?)
190            o)  Settings:
191                    x)  Special handlers for Write!
192                            +)  MIPS coproc regs
193                            +)  Alpha/MIPS/SPARC zero registers
194                            +)  x86 64/32/16-bit registers
195                    x)  Value formatter for resulting output.
196            o)  see src/debugger.c for more
197    
198    POWER/PowerPC:
199            x)  find and fix the bug which causes NetBSD/macppc to fail after
200                an install!
201            x)  NetBSD/prep 3.x triggers a possible bug in the emulator:
202                <wdc_exec_command(0xd005e514,0xd60cdd30,0,8,..)>
203                  <ata_get_xfer(0,0xd60cdd30,0,8,..)>
204                    <0x26c550(&ata_xfer_pool,2,0,8,..)>
205                    <0x35c71c(0x3f27000,0,52,8,..)>
206                  <ata_exec_xfer(0xd005e4c8,0x3f27000,0,13,..)>
207                    <atastart(0xd005e4c8,0x3f27000,0,13,..)>
208                      <__wdccommand_start(0xd005e4c8,0x3f27000,0,13,..)>
209                        <bsw1(&prep_isa_io_space_tag,0x800001f6,0,176,..)>
210                    [ wdc: write to SDH: 0xb0 (sectorsize 2, lba=1, drive 1, head 0) ]
211                        <wdcwait(0xd005e4c8,72,64,0xbb8,..)>
212                          <0x198120(0xd005e4c8,72,64,0xbb8,..)>
213                            <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
214                            <delay(100,0,0,0xbb8,..)>
215                Note: <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
216            x)  PPC optimizations; instr combs
217            x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
218                    version of AIX? (if there exists such a thing)
219            x)  macppc: adb controller; keyboard (for framebuffer mode)
220            x)  make OpenBSD/macppc work (PCI controller stuff)
221            x)  Floating point exception correctness.
222            x)  Alignment exceptions.
223    
224    Algor:
225            o)  Other models than the P5064?
226            o)  PCI interrupts... needed for stuff like the tlp NIC?
227    
228    HPCmips:
229            x)  Mouse/pad support! :)
230            x)  A NIC? (As a PCMCIA device?)
231    
232    AVR:
233            o)  Everything.
234    
235    AVR32:
236            o)  Everything. It would be good if there was NetBSD/avr32 to
237                experiment with...
238    
239    ARM:
240            o)  See netwinder_reset() in NetBSD; the current "an internal error
241                occured" message after reboot/halt is too ugly.
242            o)  ARM "wait"-like instruction?
243            o)  try to get netbsd/evbarm 3.x running (iq80321)
244            o)  make the xscale counter registers (ccnt) work
245            o)  make the ata controller usable for FreeBSD!
246            o)  zaurus for openbsd...
247            o)  debian/cats crashes because of unimplemented coproc stuff.
248                fix this?
249    
250    Test machines:
251            + dev_fb block fill and copy
252            + dev_fb draw characters (from the built-in font)?
253            + dev_fb input device? mouse pointer coordinates and buttons
254                    (allow changes in these to cause interrupts as well?)
255            + Redefine the halt() function so that it stops "sometimes
256              soon", i.e. usage in demo code should be:
257                    for (;;) {
258                            halt();
259                    }
260    
261    Better CD Image file support:
262            x)  Support CD formats that contain more than 1 track, e.g.
263                CDI files (?). These can then contain a mixture of e.g. sound
264                and data tracks, and booting from an ISO filesystem path
265                would boot from [by default] the first data track.
266                (This would make sense for e.g. Dreamcast CD images, or
267                possibly other live-CD formats.)
268    
269    Networking:
270            x)  Fix performance problems caused by only allowing a
271                single TCP packet to be unacked.
272            x)  Don't hardcode offsets into packets!
273            x)  Test with lower than 100 max tcp/udp connections,
274                to make sure that reuse works!
275            x)  Make OpenBSD work better as a guest OS!
276            x)  DHCP? Debian doesn't actually send DHCP packets, even
277                    though it claims to? So it is hard to test.
278            x)  Multiple networks per emulation, and let different
279                NICs in machines connect to different networks.
280            x)  Support VDE (vde.sf.net)? Easiest/cleanest (before a
281                redesign of the network framework has been done) is
282                probably to connect it using the current (udp) solution.
283            x)  Allow SLIP connections, possibly PPP, in addition to
284                ethernet?
285    
286    Cache simulation:
287            o)  Command line flags for:
288                    o)  CPU endianness?
289                    o)  Cache sizes? (multiple levels)
290            o)  Separate from the CPU concept, so that multi-core CPUs sharing
291                e.g. a L2 cache can be simulated (?)
292            o)  Instruction cache emulation is easiest (if separate from the
293                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
294                NOTE: if the architecture has a delay slot, then an instruction
295                slot can actually be executed as 2 instructions.
296            o)  Data cache emulation = harder; each arch's load/store routines
297                must include support? running one instruction at a time and
298                having a cpu-dependant lookup function for each instruction
299                is another option (easier to implement, but very very slow).
300    
301    Documentation:
302            x)  Note about sandboxing/security:
303                    Not all emulated instructions fail in the way they would
304                    do on real hardware (e.g. a userspace program writing to
305                    a system register might work in GXemul, but it would
306                    fail on real hardware).  Sandbox = contain from the
307                    host OS. But the emulated programs will run "less
308                    securely".
309            x)  Try NetBSD/arc 4.x! (It seems to work with disk images!)
310            x)  NetBSD/pmax 4 install instructions: xterm instead of vt100!
311            x)  DEVICE_TICK in technical.html
312            x)  Rewrite the section about experimental devices, after the
313                framebuffer acceleration has been implemented, and demos
314                written. (Symbolic names instead of numbers; example
315                use cases, etc. Mention demo files that use the various
316                features?)
317            x)  "a very simple linear framebuffer device (for graphics output)"
318                under "which machines does gxemul emulate" ==> better
319                description?
320            x)  Better description on how to set up a cross compiler?
321                Example for MIPS64.
322            o)  Automagic documentation generation?
323                    x)  machines, cpus, devices.
324                    x)  REMEMBER that several machines/devices can be in
325                            the same source file!
326            o)  Try to rewrite the install instructions for those machines
327                that use 3MAX into using CATS or hpcmips? (To remove the need
328                to use a raw ffs partition, using up all of the disk image.)
329    
330    More generic out_of_memory error reporting, and check everywhere!
331            Causes: OpenBSD has low default limits for normal users.
332                    Host is 32-bit? (32-bit hosts are limited to 4 GB or less
333                    of userspace memory.)
334                    You are actually low on RAM. (As trivial as this might sound,
335                    Unix systems usually allow processes to allocate virtual
336                    memory beyond the amount of RAM in the machine.)
337    
338    The Device subsystem:
339            x)  allow devices to be moved and/or changed in size (down to a
340                minimum size, etc, or up to a max size); if there is a collision,
341                return false. It is up to the caller to handle this situation!
342            x)  NOTE: Translations must be invalidated, both for
343                registering new devices, and for moving existing ones.
344                cpu->invalidate translation caches, for all CPUs that
345                are connected to a specific memory.
346            x)  keep track of interrupts and busses? actually, allowing any device
347                to be a bus might be a nice idea.
348            x)  turn interrupt controllers into devices? :-)
349            x)  refactor various clocks/nvram/cmos into one device?
350    
351    PCI:
352            x)  last write was ffffffff ==> fix this, it should be used
353                together with a mask to get the correct bits. also, not ALL
354                bits are size bits! (lowest 4 vs lowest 2?)
355            x)  add support for address fixups
356            x)  generalize the interrupt routing stuff (lines etc)
357    
358    Clocks and timers:
359            x)  DON'T HARDCODE 100 HZ IN cpu_mips_coproc.c!
360            x)  Test the 8253? Right now it doesn't seem to be used?
361            x)  NetWinder timeofday is incorrect!
362            x)  Cobalt TOD is incorrect!
363            x)  Go through all other machines, one by one, and fix them.
364    
365    Busses:
366            o)  Redesign the entire "mainbus" concept!
367                    x)  Busses should be placed in a hierarchical tree (?)
368                    x)  Specific clock/bus speeds, cpu speeds etc.
369            o)  Interrupt routing subsystem:
370                    x)  IF POSSIBLE, try to make the new system work with the
371                        current system, but print annoying warning messages. :)
372                        Think carefully about this.
373                    x)  Registry for all available interrupts.
374                            +)  Each interrupt controller (including CPU cores
375                                that can handle interrupts) should register its
376                                interrupts, e.g.
377                                    cpu[0].irq[3]
378                                    cpu[0].irq[3].pcmcia_slot[1]
379                                    cpu[0].irq.pci[3]
380                            +)  Note: MIPS cpus have multiple irqs in the core,
381                                while some other CPUs only have one (irq[0]
382                                or just irq).
383                    x)  Users should use interrupt _names_ instead of integers
384                        when attaching to an interrupt controller, but when
385                        asserting/deasserting irq lines, small integers must
386                        still be used (for obvious performance reasons).
387                        Figure out a way to do this nicely!
388                    x)  Any users need to say whether they need the interrupt line
389                        exclusively or allow shared access.
390                    x)  Must work with everything from native IRQs to
391                        TurboChannel/PCI/ISA/ADB/PCMCIA/...
392                    x)  Must work with SMP emulation!
393                    x)  Make it with device_add(). How does the end user find
394                        out the name of an interrupt controller/line in e.g.
395                        a configuration file?
396            o)  Synchronization over network? or at least in dyntrans within
397                one emulated machine
398            o)  Convert to real busses: TurboChannel, PCMCIA, ADB
399    
400    Config file parser:
401            o)  Rewrite it from scratch!
402            o)  Usage of any expression available through the debugger
403            o)  Support for running debugger commands (like the -c
404                command line option)
405    
406    Floating point layer:
407            o)  make it common enough to be used by _all_ emulation modes
408            o)  implement correct error/exception handling and rounding modes
409            o)  implement more helper functions (i.e. add, sub, mul...)
410            o)  non-IEEE modes (i.e. x86)?
411    
412    Userland emulation:
413            x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
414            x)  Dynamic linking? Hm.
415    
416    Sound:
417            x)  generic sound framework
418            x)  add one or more sound cards as devices; add a testmachine
419                sound card first?
420    
421    ASC SCSI controller:
422            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
423                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
424                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
425                2005/11/06/0024.html suggests that.)
426                NetBSD 4.x seems to work? :)
427    
428    Caches / memory hierarchies: (this is mostly MIPS-specific)
429            o)  src/memory*.c: Implement correct cache emulation for
430                all CPU types. (currently only R2000/R3000 is implemented)
431                (per CPU, multiple levels should be possible, associativity etc!)
432            o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
433            o)  Move the -S (fill mem with random) functionality into the
434                memory.c subsystem, not machine.c or wherever it is now
435            o)  ECC stuff, simulation of memory errors?  (Machine dependent)
436            o)  More than 4GB of emulated RAM, when run on a 32-bit host?
437                (using manual swap-out of blocks to disk, ugly)
438            o)  A global command line option should be used to turn
439                cache emulation on or off. When off, caches should be
440                faked like they are right now. When on, caches and
441                memory latencies should be emulated as correctly as
442                possible.
443    
444    File/disk/symbol handling:
445            o)  Remove some of the complexity in file format guessing, for
446                    Ultrix kernels that are actually disk images?
447            o)  Better handling of tape files
448            o)  Read function argument count and types from binaries? (ELF?)
449            o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
450                Microsoft's C++, so multiple schemes must be possible. See
451                URL at top of src/symbol_demangle.c for more info.
452    
453    Userland ABI emulation:
454            o)  see src/useremul.c
455    
456    Terminal/console:
457            o)  allow emulated serial ports to be connected to the outside
458                world in a more generic way, or even to other emulated
459                machines(?)
460    
461    Save state of the whole emulated machine, to be able to load it back
462            in later?  (Memory, all device's states, all registers and
463            so on.  Like taking a snapshot. (SimOS seems to do this,
464            according to its website.))
465    
466    Better framebuffer and X-windows functionality:
467            o)  Generalize the update_x1y1x2y2 stuff to an extend-region()
468                function...
469            o)  -Yx sometimes causes crashes.
470            o)  Simple device access to framebuffer_blockcopyfill() etc,
471                and text output (using the built-in fonts), for dev_fb.
472            o)  CLEAN UP the ugly event code
473            o)  Mouse clicks can be "missed" in the current system; this is
474                not good. They should be put on a stack of some kind.
475            o)  More 2D and 3D framebuffer acceleration.
476            o)  Non-resizable windows?  Or choose scaledown depending
477                    on size (and center the image, with a black border).
478            o)  Different scaledown on different windows?
479            o)  Non-integral scale-up? (E.g. 640x480 -> 1024x768)
480            o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
481            o)  Bug reported by Elijah Rutschman on MacOS with weird
482                keys (F5 = cursor down?).
483            o)  Keyboard and mouse events:
484                    x)  Do this for more machines than just DECstation
485                    x)  more X11 cursor keycodes
486                    x)  Keys like CTRL, ALT, SHIFT do not get through
487                        by themselves (these are necessary for example
488                        to change the font of an xterm in X in the
489                        emulator)
490            o)  Generalize the framebuffer stuff by moving _ALL_ X11
491                    specific code to src/x11.c!
492    

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