/[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 4 by dpavlin, Mon Oct 8 16:18:00 2007 UTC revision 44 by dpavlin, Mon Oct 8 16:22:56 2007 UTC
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1  $Id: TODO,v 1.127 2005/04/15 21:39:54 debug Exp $  $Id: TODO,v 1.556 2007/09/11 21:46:35 debug Exp $
2    
3  Here's a short list of what I have left to do on GXemul. This file is a mess.  Some things, in no specific order, that I'd like to fix:
4  Order is random. Don't trust it to be up-to-date.  (Some items in this list are perhaps already fixed.)
5    
6    -------------------------------------------------------------------------------
7    
8          Caches / memory hierarchies: (this is mostly MIPS-specific)  A first pass of installation regression testing of NetBSD 4.0 RC1 in GXemul:
9                  o)  MIPS coproc.c: bits in config registers should reflect  
10                      correct cache sizes for _all_ CPU types. (currently only          X  pmax (including X Windows out-of-the-box)
11                      implemented for R4000, R1x000, and a few others)          X  arc  (1.6.2 -> 4.0! Yay!)
12                  o)  src/memory*.c: Implement correct cache emulation for             hpcmips
13                      all CPU types. (currently only R2000/R3000 is implemented)             cobalt
14                      (per CPU, multiple levels should be possible,             evbmips
15                      associativity etc!)             algor
16                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)             sgimips
17                  o)  Move the -S (fill mem with random) functionality into the             cats
18                      memory.c subsystem, not machine.c or wherever it is now             evbarm
19                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)             netwinder
20                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?             prep         nej, 2.0 är senaste som funkar :(
21                      (using manual swap-out of blocks to disk, ugly)          X  macppc
22                  o)  A global command line option should be used to turn             pmppc
23                      cache emulation on or off. When off, caches should be          X  dreamcast
24                      faked like they are right now. When on, caches and          X  landisk
25                      memory latencies should be emulated as correctly as  
26                      possible.  X = done and worked fine
27    
28          Network layer:  -------------------------------------------------------------------------------
29                  o)  Multiple networks per emulation, and let different  
30                      NICs in machines connect to different networks.  Perform a second regression test pass, when the actual NetBSD 4.0 release
31                  o)  Network across multiple hosts.  has happened.
32                  o)  Fixed MAC addresses for NICs, fixed IPv4 addresses if  
33                      DHCP or RARP is used.          o)  Test all guest OSes.
34                  o)  many other issues: see src/net.c          o)  Update:
35                    URLs
36          Configure script:                  Versions
37                  o)  Only enable Alpha prefetch on pca56 etc, not on ev4, ev5.  
38                  o)  Use getopts?          o)  Make a new GXemul release:  0.4.6.1
39                  o)  X11 libs and headers via command line option?  
40                  o)  Verify that the configure script, building and running  -------------------------------------------------------------------------------
41                      the emulator works on some platforms:  
42                          +)  Irix, AIX, QNX  M88K:
43                          +)  MacOS X  (I've not tried this personally yet)          o)  FIP != NIP + 4, in rte! (Simulate delayed branch stuff.)
44                          +)  Ultrix using gcc? (Inside the emulator)          o)  cpu_dyntrans.c: MEMORY_USER_ACCESS implementation for M88K!
45            o)  xmem: Set transaction registers!
46          CPU emulation:          o)  CMMUs:
47                  o)  Binary translation:                  o)  Translation invalidations, could be optimized.
48                          +)  use an Intermediate Representation!                  o)  Move initialization from dev_mvme187 to somewhere
49                          +)  recursive translation?                      more reasonable?
50                          +)  basic blocks instead of one-instruction? :)          o)  Instruction trace by using bits of ??IP control regs.
51                          +)  on Alpha: don't assume pca56-like byte load/store?          o)  Interrupts (these are machine dependent, though).
52                          +)  write backends for UltraSparc and MIPS          o)  Implement devices etc. for one or more machine modes,
53                          +)  see src/bintrans.c for more info              to get some guest OS running. OpenBSD/mvme88k on MVME187
54                  o)  All the non-MIPS modes need a bit of work.              seems to be the smartest path to follow for now.
55                    o)  VME bus device
56          MIPS CPU emulation:                  o)  PCC2
57                  o)  Instructions:                  o)  Cirrus Logic serial port controller
58                          o)  Regression tests (see tests/README for more info):          o)  Instruction disassembly, and implementation:
59                                  o)  Floating point exception handling, and                  o)  See http://www.panggih.staff.ugm.ac.id/download/GCC/info/gcc.i5
60                                          add more instructions.                      for some strange cases of when "div" can fail (?)
61                                  o)  Finish the MIPS16 translator, and test it!                  o)  Floating point stuff
62                                  o)  MIPS ISA I, II, III, IV                  o)  "Graphics" instructions (M88110-specific)
63                                  o)  MIPS V (SIMD vector stuff?)  
64                                  o)  MDMX  (MIPS Digital Media Extension)  MIPS:
65                                  o)  MIPS 3D          o)  Nicer MIPS status bits in register dumps.
66                                  o)  MIPS MT (Multi-thread stuff) (What's this?)          o)  Floating point exception correctness.
67                          o)  Warn about mis-used bit fields (ie bits that          o)  Fix this? Triggered by NetBSD/sgimips? Hm:
68                              should be all zeroes, warn about if they are not)!                  to_be_translated(): TODO: unimplemented instruction:
69                              Both for coprocessor registers and for instruction                  000000000065102c: 00200800 (d)  rot_00  at,zr,0
70                              opcodes.          o)  Some more work on opcodes.
71                          o)  the special2 stuff is a mess right now                  x) MIPS64 revision 2.
72                          o)  warn and/or cause exceptions for unimplemented                          o)  Find out which actual CPUs implement the rev2 ISA!
73                              instructions (depending on CPU type)                          o)  DINS, DINSM, DINSU etc
74                  o)  R2000/R3000:                          o)  DROTR32 and similar MIPS64 rev 2 instructions,
75                          x)  R3000 "tri-byte stores". (What's this?)                              which have a rotation bit which differs from
76                  o)  R4000 and others:                              previous ISAs.
77                          x)  watchhi/watchlo exceptions, and other exception                  x) _MAYBE_ TX79 and R5900 actually differ in their
78                              handling details                     opcodes? Check this carefully!
79                  o)  R10000 and others:  (R12000, R14000 ?)          o)  Dyntrans: Count register updates are probably not 100% correct yet.
80                          x)  memory space, exceptions, ...          o)  (Re)implement 128-bit loads/stores for R5900.
81                          x)  use cop0 framemask for tlb lookups          o)  Coprocessor 1x (i.e. 3) should cause cp1 exceptions, not 3?
82                              (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)                  (See http://lists.gnu.org/archive/html/qemu-devel/2007-05/msg00005.html)
83                  o)  Implement load delays?  Warnings on interlocks.          o)  R4000 and others:
84                  o)  Implement all coprocessor 0 bits / functions.                  x)  watchhi/watchlo exceptions, and other exception
85                          x)  coproc 0 selectors! (R4000 ?)                      handling details
86                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird          o)  MIPS 5K* have 42 physical address bits, not 40/44?
87                          TLB/cache? 128-bit GPRs, new instructions),          o)  R10000 and others:  (R12000, R14000 ?)
88                          4K (note: NOT R4000), 5K (note: NOT R5000),                  x)  The code before the line
89                          R6000 (ISA II), R8000                          /*  reg[COP0_PAGEMASK] = cpu->cd.mips.coproc[0]->tlbs[0].mask & PAGEMASK_MASK;  */
90                  o)  Multi-cpu stuff:                      in cpu_mips.c is not correct for R10000 according to
91                          +)  SGI's NUMA architecture. Study                      Lemote's Godson patches for GXemul. TODO: Go through all
92                                  x)  Linux sources                      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
93                                  x)  SGI's specs on NUMA address space                      and make sure everything works with R10000.
94                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(                      Then test with OpenBSD/sgi?
95                          +)  Own experiments with ycx2.                  x)  Entry LO mask (as above).
96                    x)  memory space, exceptions, ...
97          Emulation of specific machines and devices:                  x)  use cop0 framemask for tlb lookups
98                  o)  Clean up stuff to make it possible to emulate multiple                      (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)
99                      (different) machines simultaneously.  
100                  o)  Use same clock for all emulations and machines.  SuperH:
101                  o)  Clean up the device stuff (registering of devices etc)          x)  Auto-generation of loads/stores! This should get rid of at least
102                  o)  Various SCSI and IDE controllers              the endianness check in each load/store.
103                  o)  PS/2-style keyboard controller (for several machines)          x)  Experiment with whether or not correct ITLB emulation is
104                  o)  Generic busses;              actually needed. (20070522: I'm turning it off today.)
105                          x)  PCI:  i/o and interrupts          x)  SH4 interrupt controller:
106                          x)  QBus-22 (DECsystem 5500, 5400?)                  x)  MASKING should be possible!
107                  o)  DECstations (pmax):          x)  SH4 DMA (0xffa00000)
108                          x)  ioasic          x)  SH4 UBC (0xff200000)
109                          x)  framebuffers:          x)  Store queues can copy 32 bytes at a time, there's no need to
110                                  +)  better cursor support, overlays?,              copy individual 32-bit words. (Performance improvement.)
111                                  +)  2D/3D acceleration, PX[G]          x)  SH4 BSC (Bus State Controller)
112                          x)  status words / control words, make this more          x)  Instruction tracing should include symbols for branch targets,
113                                  portable/cleaner              and so on, to make the output more human readable.
114                          x)  scsi controller(s): sii, DMA for asc          x)  SH3-specific devices: Pretty much everything!
115                          x)  serial controllers: ssc, scc (and more work on dc?)          x)  NetBSD/evbsh3, hpcsh! Linux?
116                          x)  nvram on decstation 5000/125:  when using X11,          x)  Floating point speed!
117                                  set console=g or similar          x)  Floating point exception correctness.
118                          x)  DECstation 5840? "xbi-based SMP"          x)  Exceptions for unaligned load/stores. OpenBSD/landisk uses
119                  o)  SGI and ARC machines (sgimips, arc):              this mechanism for its reboot code (machine_reset).
120                          x)  IP32 ("O2"): (Lots of stuff)  
121                                  +)  mec (ethernet)  Landisk SH4:
122                                  +)  pci          x)  When NetBSD/landisk 4.0 has been released, make sure it works
123                                  +)  ahc (scsi)              in the emulator. (Update documentation, etc.)
124                                  +)  ps2 kbd              NetBSD HEAD (as of April 2007) hangs during bootup, because it
125                                  +)  memory controller              turns on/off interrupts in an unfortunately synchronized way
126                                  +)  framebuffer/graphics              with dyntrans. This needs to be fixed.
127                                  +)  caches  
128                          x)  more ARCBIOS stuff  Dreamcast:
129                          x)  Memory/interrupt controllers          x)  G2 DMA
130                          x)  IP30 (Linux with graphics support?)          x)  LAN adapter (dev_mb8696x.c).  NetBSD root-on-nfs.
131                          x)  SMP / NUMA?  (SGI and various ARC machines)          x)  PVR:  Lots of stuff. See dev_pvr.c.
132                  o)  Playstation 2:          x)  Better GDROM support
133                          Hardware:  OHCI usb controller, keyboard, ...          x)  Modem
134                  o)  Cobalt:  PCI and interrupt system, ethernet,          x)  PCI bridge/bus?
135                          harddisk controller(s)          x)  Maple bus:
136                  o)  Less interesting platforms:                  x)  Correct controller input
137                          o)  newsmips:                  x)  Mouse input
138                                  o)  NetBSD/newsmips, get it to detect a "real"          x)  Software emulation of BIOS calls:
139                                      model, right now everything is 100% bogus                  x)  GD-ROM emulation: Use the GDROM device.
140                          o)  mipsco? (NetBSD)                  x)  Use the VGA font as a fake ROM font. (Better than
141                          o)  wgrisc? (big endian R3000, in OpenBSD's attic)                      nothing.)
142                          o)  other embedded / evaluation MIPS boards          x)  Make as many as possible of the KOS examples run!
143                          o)  Playstation 1? R3000A. Weird hardware?          x)  More homebrew demos/games.
144                                  No FPU, but something as coproc 2.          x)  SPU: Sound emulation (ARM cpu).
145                          o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp          x)  VME processor emulation? "(Sanyo LC8670 "Potato")" according to
146                                  (R4300, 4MB RAM, really weird memory map)              Wikipedia, LC86K87 according to Comstedt's page. See
147                  o)  non-MIPS              http://www.maushammer.com/vmu.html for a good description of
148                the differences between LC86104C and the one used in the VME.
149          File/disk handling:  
150                  o)  More than one type of disk in a machine (say, IDE + FLOPPY,  Alpha:
151                      or SCSI + IDE); how to handle this nicely?          x)  OSF1 PALcode, Virtual memory support.
152                  o)  Read function argument count and types from binaries? (ELF?)          x)  PALcode replacement! PAL1E etc opcodes...?
153                  o)  ELF: separate LE/BE (MIPS instruction format) from LSB/MSB          x)  Interrupt/exception/trap handling.
154                          (ELF structure format)?          x)  Floating point exception correctness.
155                  o)  Better handling of tape files          x)  More work on bootup memory and register contents.
156            x)  More Alpha machine types, so it could work with
157          Userland ABI emulation:              OpenBSD, FreeBSD, and Linux too?
158                  o)  see src/useremul.c  
159    SPARC (both the ISA and the machines):
160          Terminal based interactive debugger:          o)  Implement Adress space identifiers; load/stores etc.
161                  o)  see src/debugger.c          o)  Exception/trap/interrupt handling.
162            o)  Save/restore register windows etc! Both v9 and pre-v9!
163          GDB interface? (Maybe not necessary; the built-in debugger feels          o)  Finish the subcc and addcc flag computation code.
164          more useful.)          o)  Add more registers (floating point, control regs etc)
165            o)  Disassemly of some more instructions?
166          GUI, interactive debugger?  GTK+?  (The GUI _must be optional_!)          o)  Are sll etc 32-bit sign-extending or zero-extending?
167                  o)  Breakpoints (complex expressions? combinations of register          o)  Floating point exception correctness.
168                          states, memory accesses and so on)          o)  SPARC v8, v7 etc?
169                  o)  Instruction trace          o)  More machine modes and devices.
170                  o)  Disassembly of RAM (_NOT_ the same as instruction trace)  
171                  o)  Function call trace  POWER/PowerPC:
172                  o)  Inspection of CPU registers/state, coprocessor          x)  Fix DECR timer speed, so it matches the host.
173                          registers/state, any device registers/state/contents          x)  NetBSD/prep 3.x triggers a possible bug in the emulator:
174                          o)  Framebuffers in windows / tabs.              <wdc_exec_command(0xd005e514,0xd60cdd30,0,8,..)>
175                          o)  Contents of RAM                <ata_get_xfer(0,0xd60cdd30,0,8,..)>
176                  o)  "Start new emulation" should allow amount of                  <0x26c550(&ata_xfer_pool,2,0,8,..)>
177                          RAM and nr of cpus to easily be specified.                  <0x35c71c(0x3f27000,0,52,8,..)>
178                          Multiple simultaneous machines should be possible.                <ata_exec_xfer(0xd005e4c8,0x3f27000,0,13,..)>
179                  o)  Disk images.                  <atastart(0xd005e4c8,0x3f27000,0,13,..)>
180                      <__wdccommand_start(0xd005e4c8,0x3f27000,0,13,..)>
181          Regression tests:                      <bsw1(&prep_isa_io_space_tag,0x800001f6,0,176,..)>
182                  o)  see tests/                  [ wdc: write to SDH: 0xb0 (sectorsize 2, lba=1, drive 1, head 0) ]
183                        <wdcwait(0xd005e4c8,72,64,0xbb8,..)>
184          Save state of the whole emulated machine, to be able to load it back                        <0x198120(0xd005e4c8,72,64,0xbb8,..)>
185                  in later?  (Memory, all device's states, all registers and                          <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
186                  so on.  Like taking a snapshot. (SimOS seems to do this,                          <delay(100,0,0,0xbb8,..)>
187                  according to its website.))              Note: <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
188            x)  PPC optimizations; instr combs
189          Better X-windows functionality:          x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
190                  o)  CLEAN UP the ugly event code                  version of AIX? (if there exists such a thing)
191                  o)  Mouse clicks can be "missed" in the current system; this is          x)  macppc: adb controller; keyboard (for framebuffer mode)
192                      not good. They should be put on a stack of some kind.          x)  make OpenBSD/macppc work (PCI controller stuff)
193                  o)  More 2D and 3D framebuffer acceleration.          x)  Floating point exception correctness.
194                  o)  Non-resizable windows?  Or choose scaledown depending          x)  Alignment exceptions.
195                          on size (and center the image, with a black border).  
196                  o)  Different scaledown on different windows?  PReP:
197                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)          x)  Clock time! ("Bad battery blah blah")
198                  o)  Keyboard and mouse events:  
199                          x)  Do this for more machines than just DECstation  Algor:
200                          x)  more X11 cursor keycodes          o)  Other models than the P5064?
201                          x)  Keys like CTRL, ALT, SHIFT do not get through          o)  PCI interrupts... needed for stuff like the tlp NIC?
202                              by themselves (these are necessary for example  
203                              to change the font of an xterm in X in the  BeBox:
204                              emulator)          o)  Interrupts. There seems to be a problem with WDC interrupts
205                  o)  Generalize the framebuffer stuff by moving _ALL_ X11              "after a short while", although a few interrupts get through?
206                          specific code to src/x11.c!          o)  Perhaps find a copy of BeOS and try it?
207    
208          Statistics:  (this could be interesting)  Malta:
209                  o)  Save to file and show graphics. It should be possible to          o)  The Linux/Malta kernel at people.debian.org/~ths/qemu/malta/
210                      run gxemul after a simulation to just show the graphics,              almost works:
211                      or convert to a .ppm or .tga or similar.                  ./gxemul -x -o 'rd_start=0x80800000 rd_size=10000000 init=/bin/sh' -C 4KEc
212                  o)  memory accesses (to measure cache efficiency and                    -e malta 0x80800000:people.debian.org/~ths/qemu/malta/initrd.gz
213                          page coloring efficiency)                    people.debian.org/~ths/qemu/malta/vmlinux
214                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS              (Remove "init=/bin/sh" to boot into the Debian installer.)
215                  o)  percentage of time spent in different "states", such as              There are at least two things that need to be fixed:
216                      running userland code, kernel code, or idling (for CPUs                  1. PCI IDE; make Linux oops.
217                      that have such an instruction, or whenever the PC is                  2. Implement the NIC.
218                      inside a specific idle-function (address range)).  
219                      Possible additional state (for example on R3000): caches  HPCmips:
220                      disabled.          x)  Mouse/pad support! :)
221                  o)  position of read/write on (SCSI) disks          x)  A NIC? (As a PCMCIA device?)
222    
223    ARM:
224            o)  See netwinder_reset() in NetBSD; the current "an internal error
225                occured" message after reboot/halt is too ugly.
226            o)  Generic ARM "wait"-like instruction?
227            o)  try to get netbsd/evbarm 3.x or 4.x running (iq80321)
228            o)  make the xscale counter registers (ccnt) work
229            o)  make the ata controller usable for FreeBSD!
230            o)  Debian/cats crashes because of unimplemented coproc stuff.
231                fix this?
232    
233    Test machines:
234            o)  dev_fb block fill and copy
235            o)  dev_fb draw characters (from the built-in font)?
236            o)  dev_fb input device? mouse pointer coordinates and buttons
237                    (allow changes in these to cause interrupts as well?)
238            o)  Redefine the halt() function so that it stops "sometimes
239                soon", i.e. usage in demo code should be:
240                    for (;;) {
241                            halt();
242                    }
243    
244    Debugger:
245            o)  How does SMP debugging work? Does it simply use "threads"?
246                What if the guest OS (running on an emulated SMP machine)
247                has a usertask running, with userland threads?
248            o)  Try to make the debugger more modular and, if possible, reentrant!
249            o)  Memory dumps should be able to dump both physical and
250                virtual emulated memory.
251            o)  Evaluate expressions within []? That would allow stuff like
252                cpu[x] where x is an expression.
253            o)  "pc = pc + 4" doesn't work! Bug. Should work. ("pc=pc+4" works.)
254            o)  Settings:
255                    x)  Special handlers for Write!
256                            +)  MIPS coproc regs
257                            +)  Alpha/MIPS/SPARC zero registers
258                            +)  x86 64/32/16-bit registers
259                    x)  Value formatter for resulting output.
260            o)  Call stack display (back-trace) of emulated programs.
261            o)  Nicer looking output of register dumps, floating point registers,
262                etc. Warn about weird/invalid register contents.
263            o)  Ctrl-C doesn't enter the debugger on some OSes (HP-UX?)...
264    
265    Dyntrans:
266            x)  NOTE: ARM etc. that load pc-relative constants, on writes to
267                pages that contain translations, the ENTIRE page must be
268                invalidated, not just the 1/32th that was code.
269            x)  For 32-bit emulation modes, that have emulated TLBs: tlbindex
270                arrays of mapped pages? Things to think about:
271                    x)  Only 32-bit mode! (64-bit => too much code)
272                    x)  One array for global pages, and one array _PER ASID_,
273                        for those archs that support that. On M88K, there should
274                        be one array for userspace, and one for supervisor, etc.
275                    x)  Larger-than-4K-pages must fill several bits in the array.
276                    x)  No TLB search will be necessary.
277                    x)  Total host space used, for 4 KB pages: 1 MB per table,
278                        i.e. 65 MB for 32-bit MIPS, 2 MB for M88K, if one byte
279                        is used as the tlb index.
280                    x)  (The index is actually +1, so that 0 means no hit.)
281            x)  "Merge" the cur_physpage and cur_ic_page variables/pointers to
282                one? I.e. change cur_ic_page to cur_physpage.ic_page or something.
283            x)  Instruction combination collisions? How to avoid easily...
284            x)  superh -- no hostpage for e.g. 0x8c000000. devices as ram!
285            x)  Think about how to do both SHmedia and SHcompact in a reasonable
286                way! (Or AMD64 long/protected/real, for that matter.)
287            x)  68K emulation; think about how to do variable instruction
288                lengths across page boundaries.
289            x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
290                it would be reasonably simple to add; in each individual fast
291                load/store routine = a lot more work, and it would become
292                kludgy very fast.)
293            x)  Dyntrans with SMP... lots of work to be done here.
294            x)  Dyntrans with cache emulation... lots of work here as well.
295            x)  Remove the concept of base RAM completely; it would be more
296                generic to allow RAM devices to be used "anywhere".
297            o)  dev_mp doesn't work well with dyntrans yet
298            o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
299            x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
300                    so that it caches a translation (that is, an instruction
301                    word and the instr_call it was translated to the last
302                    time), so that it doesn't need to do slow
303                    to_be_translated for each end of page?
304            x)  Program Counter statistics:
305                    Per machine? What about SMP? All data to the same file?
306                    A debugger command should be possible to use to enable/
307                    disable statistics gathering.
308                    Configuration file option!
309            x)  Breakpoints:
310                    o) Physical vs virtual addresses!
311                    o) 32-bit vs 64-bit sign extension for MIPS, and others?
312            x)  INVALIDATION should cause translations in _all_ cpus to be
313                invalidated, e.g. on a write to a write-protected page
314                (containing code)
315            x)  16-bit encodings? (MIPS16, ARM Thumb, etc)
316            x)  Lots of other stuff: see src/cpus/README_DYNTRANS
317            x)  Native code generation backends... think carefully about this.
318    
319    Simple Valgrind-like checks?
320            o)  Mark every address with bits which tell whether or not the address
321                has been written to.
322            o)  What should happen when programs are loaded?  Text/data, bss (zero
323                filled). But stack space and heap is uninitialized.
324            o)  Uninitialized local variables:
325                    A load from a place on the stack which has not previously
326                    been stored to => warning. Increasing the stack pointer using
327                    any available means should reset the memory to uninitialized.
328            o)  If calls to malloc() and free() can be intercepted:
329                    o)  Access to a memory area after free() => warning.
330                    o)  Memory returned by malloc() is marked as not-initialized.
331                    o)  Non-passive, but good to have: Change the argument
332                        given to malloc, to return a slightly larger memory
333                        area, i.e.  margin_before + size + margin_after,
334                        and return the pointer  + margin_before.
335                        Any access to the margin_before or _after space results
336                        in warnings. (free() must be modified to free the
337                        actually allocated address.)
338    
339    Better CD Image file support:
340            x)  Support CD formats that contain more than 1 track, e.g.
341                CDI files (?). These can then contain a mixture of e.g. sound
342                and data tracks, and booting from an ISO filesystem path
343                would boot from [by default] the first data track.
344                (This would make sense for e.g. Dreamcast CD images, or
345                possibly other live-CD formats.)
346    
347    Networking:
348            x)  Redesign of the networking subsystem, at least the NAT translation
349                    part. The current way of allowing raw ethernet frames to be
350                    transfered to/from the emulator via UDP should probably be
351                    extended to allow the frames to be transmitted other ways as
352                    well.
353            x)  Also adding support for connecting ttys (either to xterms, or to
354                    pipes/sockets etc, or even to PPP->NAT or SLIP->NAT :-).
355            x)  Documentation updates (!) are very important, making it easier to
356                    use the (already existing) network emulation features.
357            x)  Fix performance problems caused by only allowing a
358                single TCP packet to be unacked.
359            x)  Don't hardcode offsets into packets!
360            x)  Test with lower than 100 max tcp/udp connections,
361                to make sure that reuse works!
362            x)  Make OpenBSD work better as a guest OS!
363            x)  DHCP? Debian doesn't actually send DHCP packets, even
364                    though it claims to? So it is hard to test.
365            x)  Multiple networks per emulation, and let different
366                NICs in machines connect to different networks.
367            x)  Support VDE (vde.sf.net)? Easiest/cleanest (before a
368                redesign of the network framework has been done) is
369                probably to connect it using the current (udp) solution.
370            x)  Allow SLIP connections, possibly PPP, in addition to
371                ethernet?
372    
373    Cache simulation:
374            o)  Command line flags for:
375                    o)  CPU endianness?
376                    o)  Cache sizes? (multiple levels)
377            o)  Separate from the CPU concept, so that multi-core CPUs sharing
378                e.g. a L2 cache can be simulated (?)
379            o)  Instruction cache emulation is easiest (if separate from the
380                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
381                NOTE: if the architecture has a delay slot, then an instruction
382                slot can actually be executed as 2 instructions.
383            o)  Data cache emulation = harder; each arch's load/store routines
384                must include support? running one instruction at a time and
385                having a cpu-dependant lookup function for each instruction
386                is another option (easier to implement, but very very slow).
387    
388    Documentation:
389            x)  Update the documentation regarding the testmachine interrupts.
390            x)  Note about sandboxing/security:
391                    Not all emulated instructions fail in the way they would
392                    do on real hardware (e.g. a userspace program writing to
393                    a system register might work in GXemul, but it would
394                    fail on real hardware).  Sandbox = contain from the
395                    host OS. But the emulated programs will run "less
396                    securely".
397            x)  Try NetBSD/arc 4.x! (It seems to work with disk images!)
398            x)  NetBSD/pmax 4 install instructions: xterm instead of vt100!
399            x)  Rewrite the section about experimental devices, after the
400                framebuffer acceleration has been implemented, and demos
401                written. (Symbolic names instead of numbers; example
402                use cases, etc. Mention demo files that use the various
403                features?)
404            x)  "a very simple linear framebuffer device (for graphics output)"
405                under "which machines does gxemul emulate" ==> better
406                description?
407    
408    The Device subsystem:
409            x)  allow devices to be moved and/or changed in size (down to a
410                minimum size, etc, or up to a max size); if there is a collision,
411                return false. It is up to the caller to handle this situation!
412            x)  NOTE: Translations must be invalidated, both for
413                registering new devices, and for moving existing ones.
414                cpu->invalidate translation caches, for all CPUs that
415                are connected to a specific memory.
416    
417    PCI:
418            x)  Pretty much everything related to runtime configuration, device
419                slots, interrupts, etc must be redesigned/cleaned up. The current
420                code is very hardcoded and ugly.
421            o)  Allow cards to be added/removed during runtime more easily.
422            o)  Allow cards to be enabled/disabled (i/o ports, etc, like
423                NetBSD needs for disk controller detection).
424            o)  Allow devices to be moved in memory during runtime.
425            o)  Interrupts per PCI slot, etc. (A-D).
426            o)  PCI interrupt controller logic... very hard to get right,
427                because these differ a lot from one machine to the next.
428            x)  last write was ffffffff ==> fix this, it should be used
429                together with a mask to get the correct bits. also, not ALL
430                bits are size bits! (lowest 4 vs lowest 2?)
431            x)  add support for address fixups
432            x)  generalize the interrupt routing stuff (lines etc)
433    
434    Clocks and timers:
435            x)  Fix the PowerPC DECR interrupt speed! (MacPPC and PReP speed, etc.)
436            x)  DON'T HARDCODE 100 HZ IN cpu_mips_coproc.c!
437            x)  NetWinder timeofday is incorrect! Huh? grep -R for ta_rtc_read in
438                NetBSD sources; it doesn't seem to be initialized _AT ALL_?!
439            x)  Cobalt TOD is incorrect!
440            x)  Go through all other machines, one by one, and fix them.
441    
442    Config file parser:
443            o)  Rewrite it from scratch!
444            o)  Usage of any expression available through the debugger
445            o)  Allow interrupt controllers to be added! and interrupts
446                to be used in more ways than before
447            o)  Support for running debugger commands (like the -c
448                command line option)
449    
450    Floating point layer:
451            o)  make it common enough to be used by _all_ emulation modes
452            o)  implement correct error/exception handling and rounding modes
453            o)  implement more helper functions (i.e. add, sub, mul...)
454            o)  non-IEEE modes (i.e. x86)?
455    
456    Userland emulation:
457            x)  Try to prefix "/emul/mips/" or similar to all filenames,
458                and only if that fails, try the given filename.
459                Read this setting from an environment variable, and only
460                if there is none, fall back to hardcoded string.
461            x)  File descriptor (0,1,2) assumptions? Find and fix these?
462            x)  Dynamic linking!
463            x)  Lots of stuff; freebsd, netbsd, linux, ... syscalls.
464            x)  Initial register/stack contents (environment, command line args).
465            x)  Return value (from main).
466            x)  mmap emulation layer
467            x)  errno emulation layer
468            x)  ioctl emulation layer for all devices :-[
469            x)  struct conversions for many syscalls
470    
471    Sound:
472            x)  generic sound framework
473            x)  add one or more sound cards as devices; add a testmachine
474                sound card first?
475            x)  Dreamcast sound? Generic PCI sound cards?
476    
477    ASC SCSI controller:
478            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
479                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
480                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
481                2005/11/06/0024.html suggests that.)
482                NetBSD 4.x seems to work? :)
483    
484    Caches / memory hierarchies: (this is mostly MIPS-specific)
485            o)  src/memory*.c: Implement correct cache emulation for
486                all CPU types. (currently only R2000/R3000 is implemented)
487                (per CPU, multiple levels should be possible, associativity etc!)
488            o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
489            o)  Move the -S (fill mem with random) functionality into the
490                memory.c subsystem, not machine.c or wherever it is now
491            o)  ECC stuff, simulation of memory errors?  (Machine dependent)
492            o)  More than 4GB of emulated RAM, when run on a 32-bit host?
493                (using manual swap-out of blocks to disk, ugly)
494            o)  A global command line option should be used to turn
495                cache emulation on or off. When off, caches should be
496                faked like they are right now. When on, caches and
497                memory latencies should be emulated as correctly as
498                possible.
499    
500    File/disk/symbol handling:
501            o)  Make sure that disks can be added/removed during runtime!
502                (Perhaps this needs a reasonably large re-write.)
503            o)  Remove some of the complexity in file format guessing, for
504                    Ultrix kernels that are actually disk images?
505            o)  Remove temporary files (/tmp/gxemul.blahblah) if loading fails
506                for some reason (unrecognized file, etc).
507            o)  Better handling of tape files      
508            o)  Read function argument count and types from binaries? (ELF?)
509            o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
510                Microsoft's C++, so multiple schemes must be possible. See
511                URL at top of src/symbol_demangle.c for more info.
512    
513    Userland ABI emulation:
514            o)  see src/useremul.c
515    
516    Better framebuffer and X-windows functionality:
517            o)  Do a complete rewrite of the framebuffer/console stuff, so that:
518                    1)  It does not rely on X11 specifically.
519                    2)  It is possible to interact with emulated framebuffers
520                        and consoles "remotely", e.g. via a web page which
521                        controls multiple virtualized machines.
522                    3)  It is possible to run on (hypothetical) non-X11
523                        graphics systems.
524            o)  Generalize the update_x1y1x2y2 stuff to an extend-region()
525                function...
526            o)  -Yx sometimes causes crashes.
527            o)  Simple device access to framebuffer_blockcopyfill() etc,
528                and text output (using the built-in fonts), for dev_fb.
529            o)  CLEAN UP the ugly event code
530            o)  Mouse clicks can be "missed" in the current system; this is
531                not good. They should be put on a stack of some kind.
532            o)  More 2D and 3D framebuffer acceleration.
533            o)  Non-resizable windows?  Or choose scaledown depending
534                    on size (and center the image, with a black border).
535            o)  Different scaledown on different windows?
536            o)  Non-integral scale-up? (E.g. 640x480 -> 1024x768)
537            o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
538            o)  Bug reported by Elijah Rutschman on MacOS with weird
539                keys (F5 = cursor down?).
540            o)  Keyboard and mouse events:
541                    x)  Do this for more machines than just DECstation
542                    x)  more X11 cursor keycodes
543                    x)  Keys like CTRL, ALT, SHIFT do not get through
544                        by themselves (these are necessary for example
545                        to change the font of an xterm in X in the
546                        emulator)
547            o)  Generalize the framebuffer stuff by moving _ALL_ X11
548                    specific code to a separate module.
549    
550    -------------------------------------------------------------------------------
551    

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