/[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 32 by dpavlin, Mon Oct 8 16:20:58 2007 UTC
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1  $Id: TODO,v 1.125 2005/03/06 08:21:10 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    
7          Caches / memory hierarchies: (this is mostly MIPS-specific)  Dyntrans:
8                  o)  MIPS coproc.c: bits in config registers should reflect          x)  Instruction combination collisions? How to avoid easily...
9                      correct cache sizes for _all_ CPU types. (currently only          x)  Think about how to do both SHmedia and SHcompact in a reasonable
10                      implemented for R4000, R1x000, and a few others)              way! (Or AMD64 long/protected/real, for that matter.)
11                  o)  src/memory*.c: Implement correct cache emulation for          x)  68K emulation; think about how to do variable instruction
12                      all CPU types. (currently only R2000/R3000 is implemented)              lengths across page boundaries.
13                      (per CPU, multiple levels should be possible,          x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
14                      associativity etc!)              it would be reasonably simple to add; in each individual fast
15                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)              load/store routine = a lot more work, and it would become
16                  o)  Move the -S (fill mem with random) functionality into the              kludgy very fast.)
17                      memory.c subsystem, not machine.c or wherever it is now          x)  Dyntrans with SMP... lots of work to be done here.
18                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)          x)  Dyntrans with cache emulation... lots of work here as well.
19                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?          o)  dev_mp doesn't work well with dyntrans yet
20                      (using manual swap-out of blocks to disk, ugly)          o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
21                  o)  A global command line option should be used to turn          x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
22                      cache emulation on or off. When off, caches should be                  so that it caches a translation (that is, an instruction
23                      faked like they are right now. When on, caches and                  word and the instr_call it was translated to the last
24                      memory latencies should be emulated as correctly as                  time), so that it doesn't need to do slow
25                      possible.                  to_be_translated for each end of page?
26            x)  Program Counter statistics:
27          Network layer:                  Per machine? What about SMP? All data to the same file?
28                  o)  Multiple networks per emulation, and let different                  A debugger command should be possible to use to enable/
29                      NICs in machines connect to different networks.                  disable statistics gathering.
30                  o)  Network across multiple hosts.                  Configuration file option!
31                  o)  Fixed MAC addresses for NICs, fixed IPv4 addresses if          x)  Breakpoints:
32                      DHCP or RARP is used.                  o) Physical vs virtual addresses!
33                  o)  many other issues: see src/net.c                  o) 32-bit vs 64-bit sign extension for MIPS, and others?
34            x)  INVALIDATION should cause translations in _all_ cpus to be
35          Configure script:              invalidated, e.g. on a write to a write-protected page
36                  o)  Only enable Alpha prefetch on pca56 etc, not on ev4, ev5.              (containing code)
37                  o)  Use getopts?          x)  16-bit encodings? (MIPS16, ARM Thumb, 32-bit SH on SH64)
38                  o)  X11 libs and headers via command line option?          x)  Lots of other stuff: see src/cpus/README_DYNTRANS
39                  o)  Verify that the configure script, building and running          x)  true recompilation backend? think carefully about this,
40                      the emulator works on some platforms:              experiment in a separate project (not in GXemul)
41                          +)  Irix, AIX, QNX                  o) First test would be to just implement a simple
42                          +)  MacOS X  (I've not tried this personally yet)                     instruction such as MIPS' addiu or lui, on AMD64
43                          +)  Ultrix using gcc? (Inside the emulator)                     hosts...
44    
45          CPU emulation:  Simple Valgrind-like checks?
46                  o)  Binary translation:          o)  Mark every address with bits which tell whether or not the address
47                          +)  use an Intermediate Representation!              has been written to.
48                          +)  recursive translation?          o)  What should happen when programs are loaded?  Text/data, bss (zero
49                          +)  basic blocks instead of one-instruction? :)              filled). But stack space and heap is uninitialized.
50                          +)  on Alpha: don't assume pca56-like byte load/store?          o)  Uninitialized local variables:
51                          +)  write backends for UltraSparc and MIPS                  A load from a place on the stack which has not previously
52                          +)  see src/bintrans.c for more info                  been stored to => warning. Increasing the stack pointer using
53                    any available means should reset the memory to uninitialized.
54          MIPS CPU emulation:          o)  If calls to malloc() and free() can be intercepted:
55                  o)  Instructions:                  o)  Access to a memory area after free() => warning.
56                          o)  Regression tests (see tests/README for more info):                  o)  Memory returned by malloc() is marked as not-initialized.
57                                  o)  Floating point exception handling, and                  o)  Non-passive, but good to have: Change the argument
58                                          add more instructions.                      given to malloc, to return a slightly larger memory
59                                  o)  Finish the MIPS16 translator, and test it!                      area, i.e.  margin_before + size + margin_after,
60                                  o)  MIPS ISA I, II, III, IV                      and return the pointer  + margin_before.
61                                  o)  MIPS V (SIMD vector stuff?)                      Any access to the margin_before or _after space results
62                                  o)  MDMX  (MIPS Digital Media Extension)                      in warnings. (free() must be modified to free the
63                                  o)  MIPS 3D                      actually allocated address.)
64                                  o)  MIPS MT (Multi-thread stuff) (What's this?)  
65                          o)  Warn about mis-used bit fields (ie bits that  MIPS:
66                              should be all zeroes, warn about if they are not)!          o)  Nicer MIPS status bits in register dumps.
67                              Both for coprocessor registers and for instruction          o)  Alignment exceptions.
68                              opcodes.          o)  Floating point exception correctness.
69                          o)  the special2 stuff is a mess right now          o)  Fix this? Triggered by NetBSD/sgimips? Hm:
70                          o)  warn and/or cause exceptions for unimplemented                  to_be_translated(): TODO: unimplemented instruction:
71                              instructions (depending on CPU type)                  000000000065102c: 00200800 (d)  rot_00  at,zr,0
72                  o)  R2000/R3000:          o)  Some more work on opcodes.
73                          x)  R3000 "tri-byte stores". (What's this?)                  x) MIPS64 revision 2.
74                  o)  R4000 and others:                          o)  Find out which actual CPUs implement the rev2 ISA!
75                          x)  watchhi/watchlo exceptions, and other exception                          o)  DROTR32 and similar MIPS64 rev 2 instructions,
76                              handling details                              which have a rotation bit which differs from
77                  o)  R10000 and others:  (R12000, R14000 ?)                              previous ISAs.
78                          x)  memory space, exceptions, ...                          o)  EI and DI instructions for MIPS64/32 rev 2.
79                          x)  use cop0 framemask for tlb lookups                              NOTE: These are _NOT_ the same as for R5900!
80                              (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) _MAYBE_ TX79 and R5900 actually differ in their
81                  o)  Implement load delays?  Warnings on interlocks.                     opcodes? Check this carefully!
82                  o)  Implement all coprocessor 0 bits / functions.          o)  Dyntrans: Count register updates are probably not 100% correct yet.
83                          x)  coproc 0 selectors! (R4000 ?)          o)  Refactor code for performance and readability/maintainability.
84                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird          o)  (Re)implement 128-bit loads/stores for R5900.
85                          TLB/cache? 128-bit GPRs, new instructions),          o)  R4000 and others:
86                          4K (note: NOT R4000), 5K (note: NOT R5000),                  x)  watchhi/watchlo exceptions, and other exception
87                          R6000 (ISA II), R8000                      handling details
88                  o)  Multi-cpu stuff:          o)  R10000 and others:  (R12000, R14000 ?)
89                          +)  SGI's NUMA architecture. Study                  x)  memory space, exceptions, ...
90                                  x)  Linux sources                  x)  use cop0 framemask for tlb lookups
91                                  x)  SGI's specs on NUMA address space                      (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                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(  
93                          +)  Own experiments with ycx2.  SuperH:
94            x)  DMA (0xffa00000)
95          Emulation of specific machines and devices:          x)  Instruction tracing should include symbols for branch targets,
96                  o)  Clean up stuff to make it possible to emulate multiple              and so on...
97                      (different) machines simultaneously.          x)  SH4 interrupt controller:
98                  o)  Use same clock for all emulations and machines.                  x)  Implement correct priorities of interrupts
99                  o)  Clean up the device stuff (registering of devices etc)          x)  SH4 BSC (Bus State Controller)
100                  o)  Various SCSI and IDE controllers          x)  NetBSD/evbsh3, dreamcast, mmeye, hpcsh! Linux?
101                  o)  PS/2-style keyboard controller (for several machines)          x)  Replace pc-relative loads with immediate load, if within the
102                  o)  Generic busses;              same page. (Similar to the same optimization for ARM.)
103                          x)  PCI:  i/o and interrupts          x)  Floating point exception correctness.
104                          x)  QBus-22 (DECsystem 5500, 5400?)          x)  Floating point speed!
105                  o)  DECstations (pmax):          x)  Think carefully about how to implement SH5/SH64 (for evbsh5).
106                          x)  ioasic  
107                          x)  framebuffers:  Dreamcast:
108                                  +)  better cursor support, overlays?,          x)  CD image bootup:
109                                  +)  2D/3D acceleration, PX[G]                  0)  Find IP.BIN, and load it to 0x8c008000.
110                          x)  status words / control words, make this more                  1)  Run code at 0x8c008300 (SEGA license code).
111                                  portable/cleaner                  2)  When the license code runs a "boot menu" syscall,
112                          x)  scsi controller(s): sii, DMA for asc                      load the 1ST_READ.BIN file (unscrambled?) to 0x8c010000.
113                          x)  serial controllers: ssc, scc (and more work on dc?)                  3)  Run code at 0x8c00b800 (Bootstrap 1). This will in turn
114                          x)  nvram on decstation 5000/125:  when using X11,                      jump to 0x8c00e000 (Bootstrap 2), and then jump to
115                                  set console=g or similar                      0x8c010000, to start the program.
116                          x)  DECstation 5840? "xbi-based SMP"                  (Try with e.g. Comstedt's Serial IP Slave, to make sure it
117                  o)  SGI and ARC machines (sgimips, arc):                  works as expected.)
118                          x)  IP32 ("O2"): (Lots of stuff)          x)  LAN adapter.
119                                  +)  mec (ethernet)          x)  PVR:  Lots of stuff. See dev_pvr.c.
120                                  +)  pci          x)  Maple bus:
121                                  +)  ahc (scsi)                  x)  Correct controller input
122                                  +)  ps2 kbd                  x)  Mouse input
123                                  +)  memory controller          x)  PROM/BIOS calls:
124                                  +)  framebuffer/graphics                  x)  GD-ROM emulation
125                                  +)  caches          x)  NetBSD/dreamcast: Root on nfs?
126                          x)  more ARCBIOS stuff          x)  Linux/dreamcast? (The gentoo kernel currently crashes.)
127                          x)  Memory/interrupt controllers          x)  More homebrew demos/games.
128                          x)  IP30 (Linux with graphics support?)          x)  Sound emulation (ARM cpu).
129                          x)  SMP / NUMA?  (SGI and various ARC machines)          x)  VME processor emulation?
130                  o)  Cobalt:  PCI and interrupt system, ethernet,  
131                          harddisk controller(s)  Transputer:
132                  o)  Playstation 2:          x)  Implement support for Helios binaries.
133                          Hardware:  OHCI usb controller, keyboard, IDE, ...          x)  Stack and register contents at startup?
134                          Has an R3000A as a subsystem (!)          x)  Figure out how to boot an entire Helios distribution.
135                  o)  hpcmips:  framebuffer(s) and harddisk controller,          x)  Implement all instructions. :)
136                          among other things  
137                  o)  newsmips:  RCA1802/RCA1805, CHIP8:
138                          o)  NetBSD/newsmips, get it to detect a "real"          x)  CHIP8 -> RCA180x conversion
139                              model, right now everything is 100% bogus                  x)  Think about how to do dual-mode, variable-instr-length
140                  o)  Less interesting platforms:                      ISAs, and switch between modes.
141                          o)  mipsco? (NetBSD)                  x)  1805 "extended" opcode -> trigger CHIP8 emulation?
142                          o)  wgrisc? (big endian R3000, in OpenBSD's attic)                          That is, all calls 0NNN could point to 0x68 opcodes,
143                          o)  other embedded / evaluation MIPS boards                          which, if running on a 1802 in CHIP8-emulation-mode,
144                          o)  Playstation 1? R3000A. Weird hardware?                          would be manually interpreted.
145                                  No FPU, but something as coproc 2.                  x)  Better solution:
146                          o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp                          CHIP8 calls to 00xx => handle at high level,
147                                  (R4300, 4MB RAM, really weird memory map)                                calls to 0xxx in general = call 180X machine code
148                                    (0000 = reboot?)
149          File/disk handling:          x)  1802 info: http://www.nyx.net/~lturner/public_html/Cosmac.html
150                  o)  Read function argument count and types from binaries? (ELF?)              and:  http://www.elf-emulation.com/1802.html
151                  o)  ELF: separate LE/BE (MIPS instruction format) from LSB/MSB          x)  1805 extended opcodes: Implement at least disassembly support!
152                          (ELF structure format)?          x)  Keyboard input.
153                  o)  Better handling of tape files          x)  Sound (beep only).
154            x)  Slow-down to correct speed? Wikipedia: "it was usually operated
155          Userland ABI emulation:              at 3.58 MHz/2 to suit the requirements of the 1861 chip which
156                  o)  see src/useremul.c              gave a speed of a little over 100,000 instructions per second"
157                (Note that _CHIP8_ emulation would then be even slower.)
158          Terminal based interactive debugger:          x)  SCHIP48 (Super) emulation:
159                  o)  see src/debugger.c                  Some more opcodes, 128x64 framebuffer, larger
160                    sprites and fonts.
161          GDB interface? (Maybe not necessary; the built-in debugger feels  
162          more useful.)  Alpha:
163            x)  OSF1 PALcode, Virtual memory support.
164          GUI, interactive debugger?  GTK+?  (The GUI _must be optional_!)          x)  PALcode replacement! PAL1E etc opcodes...?
165                  o)  Breakpoints (complex expressions? combinations of register          x)  Interrupt/exception/trap handling.
166                          states, memory accesses and so on)          x)  Floating point exception correctness.
167                  o)  Instruction trace          x)  More work on bootup memory and register contents.
168                  o)  Disassembly of RAM (_NOT_ the same as instruction trace)          x)  More Alpha machine types, so it could work with
169                  o)  Function call trace              OpenBSD, FreeBSD, and Linux too?
170                  o)  Inspection of CPU registers/state, coprocessor  
171                          registers/state, any device registers/state/contents  SPARC:
172                          o)  Framebuffers in windows / tabs.          o)  Implement Adress space identifiers; load/stores etc.
173                          o)  Contents of RAM          o)  Save/restore register windows etc!
174                  o)  "Start new emulation" should allow amount of          o)  Finish the subcc and addcc flag computation code.
175                          RAM and nr of cpus to easily be specified.          o)  Add more registers (floating point, control regs etc)
176                          Multiple simultaneous machines should be possible.          o)  Exception/trap handling.
177                  o)  Disk images.          o)  Disassemly of some more instructions?
178            o)  Are sll etc 32-bit sign-extending or zero-extending?
179          Regression tests:          o)  Finish the GDB register stuff.
180                  o)  see tests/          x)  Floating point exception correctness.
181            o)  SPARC v8, v7 etc?
182          Save state of the whole emulated machine, to be able to load it back  
183                  in later?  (Memory, all device's states, all registers and  Debugger:
184                  so on.  Like taking a snapshot. (SimOS seems to do this,          o)  How does SMP debugging work? Does it simply use "threads"?
185                  according to its website.))                  What if the guest OS (running on an emulated SMP machine)
186                    has a usertask running, with userland threads?
187          Better X-windows functionality:          o)  Try to make the debugger more modular and, if possible, reentrant!
188                  o)  CLEAN UP the ugly event code          o)  Remove the emul command? (But show network info if showing
189                  o)  Mouse clicks can be "missed" in the current system; this is                  machines?)
190                      not good. They should be put on a stack of some kind.          o)  Settings:
191                  o)  More 2D and 3D framebuffer acceleration.                  x)  Special handlers for Write!
192                  o)  Non-resizable windows?  Or choose scaledown depending                          +)  MIPS coproc regs
193                          on size (and center the image, with a black border).                          +)  Alpha/MIPS/SPARC zero registers
194                  o)  Different scaledown on different windows?                          +)  x86 64/32/16-bit registers
195                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)                  x)  Value formatter for resulting output.
196                  o)  Keyboard and mouse events:          o)  see src/debugger.c for more
197                          x)  Do this for more machines than just DECstation  
198                          x)  more X11 cursor keycodes  POWER/PowerPC:
199                          x)  Keys like CTRL, ALT, SHIFT do not get through          x)  find and fix the bug which causes NetBSD/macppc to fail after
200                              by themselves (these are necessary for example              an install!
201                              to change the font of an xterm in X in the          x)  NetBSD/prep 3.x triggers a possible bug in the emulator:
202                              emulator)              <wdc_exec_command(0xd005e514,0xd60cdd30,0,8,..)>
203                  o)  Generalize the framebuffer stuff by moving _ALL_ X11                <ata_get_xfer(0,0xd60cdd30,0,8,..)>
204                          specific code to src/x11.c!                  <0x26c550(&ata_xfer_pool,2,0,8,..)>
205                    <0x35c71c(0x3f27000,0,52,8,..)>
206          Statistics:  (this could be interesting)                <ata_exec_xfer(0xd005e4c8,0x3f27000,0,13,..)>
207                  o)  Save to file and show graphics. It should be possible to                  <atastart(0xd005e4c8,0x3f27000,0,13,..)>
208                      run gxemul after a simulation to just show the graphics,                    <__wdccommand_start(0xd005e4c8,0x3f27000,0,13,..)>
209                      or convert to a .ppm or .tga or similar.                      <bsw1(&prep_isa_io_space_tag,0x800001f6,0,176,..)>
210                  o)  memory accesses (to measure cache efficiency and                  [ wdc: write to SDH: 0xb0 (sectorsize 2, lba=1, drive 1, head 0) ]
211                          page coloring efficiency)                      <wdcwait(0xd005e4c8,72,64,0xbb8,..)>
212                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS                        <0x198120(0xd005e4c8,72,64,0xbb8,..)>
213                  o)  percentage of time spent in different "states", such as                          <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
214                      running userland code, kernel code, or idling (for CPUs                          <delay(100,0,0,0xbb8,..)>
215                      that have such an instruction, or whenever the PC is              Note: <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
216                      inside a specific idle-function (address range)).          x)  PPC optimizations; instr combs
217                      Possible additional state (for example on R3000): caches          x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
218                      disabled.                  version of AIX? (if there exists such a thing)
219                  o)  position of read/write on (SCSI) disks          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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