/[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 42 by dpavlin, Mon Oct 8 16:22:32 2007 UTC
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1  $Id: TODO,v 1.139 2005/06/23 06:55:43 debug Exp $  $Id: TODO,v 1.536 2007/06/15 22:30:17 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          Caches / memory hierarchies: (this is mostly MIPS-specific)  M88K:
7                  o)  MIPS coproc.c: bits in config registers should reflect          o)  Neither NIP nor FIP valid in rte?
8                      correct cache sizes for _all_ CPU types. (currently only          o)  FIP != NIP + 4, in rte! (Simulate delayed branch stuff.)
9                      implemented for R4000, R1x000, and a few others)          o)  cpu_dyntrans.c: MEMORY_USER_ACCESS implementation for M88K!
10                  o)  src/memory*.c: Implement correct cache emulation for          o)  xmem: Set transaction registers!
11                      all CPU types. (currently only R2000/R3000 is implemented)          o)  CMMUs:
12                      (per CPU, multiple levels should be possible,                  o)  Translation invalidations, could be optimized.
13                      associativity etc!)                  o)  Move initialization from dev_mvme187 to somewhere
14                  o)  R2000/R3000 isn't _100%_ correct, just almost correct :)                      more reasonable?
15                  o)  Move the -S (fill mem with random) functionality into the          o)  Instruction trace by using bits of ??IP control regs.
16                      memory.c subsystem, not machine.c or wherever it is now          o)  Interrupts (these are machine dependent, though).
17                  o)  ECC stuff, simulation of memory errors?  (Machine dependant)          o)  Implement devices etc. for one or more machine modes,
18                  o)  More than 4GB of emulated RAM, when run on a 32-bit host?              to get some guest OS running. OpenBSD/mvme88k on MVME187
19                      (using manual swap-out of blocks to disk, ugly)              seems to be the smartest path to follow for now.
20                  o)  A global command line option should be used to turn                  o)  VME bus device
21                      cache emulation on or off. When off, caches should be                  o)  PCC2
22                      faked like they are right now. When on, caches and                  o)  Cirrus Logic serial port controller
23                      memory latencies should be emulated as correctly as          o)  Instruction disassembly, and implementation:
24                      possible.                  o)  See http://www.panggih.staff.ugm.ac.id/download/GCC/info/gcc.i5
25                        for some strange cases of when "div" can fail (?)
26          Network layer:                  o)  Floating point stuff
27                  o)  Multiple networks per emulation, and let different                  o)  "Graphics" instructions (M88110-specific)
28                      NICs in machines connect to different networks.  
29                  o)  many other issues: see src/net.c  MIPS:
30            o)  Nicer MIPS status bits in register dumps.
31          CPU emulation:          o)  Floating point exception correctness.
32                  o)  Binary translation:          o)  Fix this? Triggered by NetBSD/sgimips? Hm:
33                          +)  use an Intermediate Representation!                  to_be_translated(): TODO: unimplemented instruction:
34                          +)  recursive translation?                  000000000065102c: 00200800 (d)  rot_00  at,zr,0
35                          +)  basic blocks instead of one-instruction? :)          o)  Some more work on opcodes.
36                          +)  on Alpha: don't assume pca56-like byte load/store?                  x) MIPS64 revision 2.
37                          +)  write backends for UltraSparc and MIPS                          o)  Find out which actual CPUs implement the rev2 ISA!
38                          +)  see src/bintrans.c for more info                          o)  DINS, DINSM, DINSU etc
39                  o)  Dynamic-but-not-binary translation?                          o)  DROTR32 and similar MIPS64 rev 2 instructions,
40                  o)  All the non-MIPS modes need a bit of work.                              which have a rotation bit which differs from
41                                previous ISAs.
42          MIPS CPU emulation:                  x) _MAYBE_ TX79 and R5900 actually differ in their
43                  o)  Instructions:                     opcodes? Check this carefully!
44                          o)  Regression tests (see tests/README for more info):          o)  Dyntrans: Count register updates are probably not 100% correct yet.
45                                  o)  Floating point exception handling, and          o)  Refactor code for performance and readability/maintainability.
46                                          add more instructions.          o)  (Re)implement 128-bit loads/stores for R5900.
47                                  o)  Finish the MIPS16 translator, and test it!          o)  Coprocessor 1x (i.e. 3) should cause cp1 exceptions, not 3?
48                                  o)  MIPS ISA I, II, III, IV                  (See http://lists.gnu.org/archive/html/qemu-devel/2007-05/msg00005.html)
49                                  o)  MIPS V (SIMD vector stuff?)          o)  R4000 and others:
50                                  o)  MDMX  (MIPS Digital Media Extension)                  x)  watchhi/watchlo exceptions, and other exception
51                                  o)  MIPS 3D                      handling details
52                                  o)  MIPS MT (Multi-thread stuff) (What's this?)          o)  MIPS 5K* have 42 physical address bits, not 40/44?
53                          o)  Warn about mis-used bit fields (ie bits that          o)  R10000 and others:  (R12000, R14000 ?)
54                              should be all zeroes, warn about if they are not)!                  x)  The code before the line
55                              Both for coprocessor registers and for instruction                          /*  reg[COP0_PAGEMASK] = cpu->cd.mips.coproc[0]->tlbs[0].mask & PAGEMASK_MASK;  */
56                              opcodes.                      in cpu_mips.c is not correct for R10000 according to
57                          o)  the special2 stuff is a mess right now                      Lemote's Godson patches for GXemul. TODO: Go through all
58                          o)  warn and/or cause exceptions for unimplemented                      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
59                              instructions (depending on CPU type)                      and make sure everything works with R10000.
60                  o)  R2000/R3000:                      Then test with OpenBSD/sgi?
61                          x)  R3000 "tri-byte stores". (What's this?)                  x)  Entry LO mask (as above).
62                  o)  R4000 and others:                  x)  memory space, exceptions, ...
63                          x)  watchhi/watchlo exceptions, and other exception                  x)  use cop0 framemask for tlb lookups
64                              handling details                      (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)
65                  o)  R10000 and others:  (R12000, R14000 ?)  
66                          x)  memory space, exceptions, ...  SuperH:
67                          x)  use cop0 framemask for tlb lookups          x)  Auto-generation of loads/stores! This should get rid of at least
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)              the endianness check in each load/store.
69                  o)  Implement load delays?  Warnings on interlocks.          x)  Experiment with whether or not correct ITLB emulation is
70                  o)  Implement all coprocessor 0 bits / functions.              actually needed. (20070522: I'm turning it off today.)
71                          x)  coproc 0 selectors! (R4000 ?)          x)  SH4 interrupt controller:
72                  o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird                  x)  MASKING should be possible!
73                          TLB/cache? 128-bit GPRs, new instructions),          x)  SH4 DMA (0xffa00000)
74                          4K (note: NOT R4000), 5K (note: NOT R5000),          x)  SH4 UBC (0xff200000)
75                          R6000 (ISA II), R8000          x)  Store queues can copy 32 bytes at a time, there's no need to
76                  o)  Multi-cpu stuff:              copy individual 32-bit words. (Performance improvement.)
77                          +)  SGI's NUMA architecture. Study          x)  SH4 BSC (Bus State Controller)
78                                  x)  Linux sources          x)  Instruction tracing should include symbols for branch targets,
79                                  x)  SGI's specs on NUMA address space              and so on, to make the output more human readable.
80                          +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(          x)  SH3-specific devices: Pretty much everything!
81                          +)  Own experiments with ycx2.          x)  NetBSD/evbsh3, hpcsh! Linux?
82            x)  Floating point speed!
83          Emulation of specific machines and devices:          x)  Floating point exception correctness.
84                  o)  Use same clock for all emulations and machines.          x)  NetBSD HEAD (as of April 2007) hangs during bootup, because it
85                  o)  Clean up the device stuff (registering of devices etc)              turns on/off interrupts in an unfortunately synchronized way
86                  o)  Various SCSI and IDE controllers              with dyntrans. This needs to be fixed.
87                  o)  PS/2-style keyboard controller (for several machines)          x)  Exceptions for unaligned load/stores. OpenBSD/landisk uses
88                  o)  Generic busses;              this mechanism for its reboot code (machine_reset).
89                          x)  PCI:  i/o and interrupts          x)  Think carefully about how to implement SH5/SH64 (for evbsh5).
90                          x)  QBus-22 (DECsystem 5500, 5400?)  
91                  o)  DECstations (pmax):  Landisk SH4:
92                          x)  ioasic          x)  When NetBSD/landisk 4.0 has been released, make sure it works
93                          x)  framebuffers:              in the emulator. (Update documentation, etc.)
94                                  +)  better cursor support, overlays?,  
95                                  +)  2D/3D acceleration, PX[G]  Dreamcast:
96                          x)  status words / control words, make this more          x)  G2 DMA
97                                  portable/cleaner          x)  LAN adapter (dev_mb8696x.c).  NetBSD root-on-nfs.
98                          x)  scsi controller(s): sii, DMA for asc          x)  PVR:  Lots of stuff. See dev_pvr.c.
99                          x)  serial controllers: ssc, scc (and more work on dc?)          x)  Better GDROM support
100                          x)  nvram on decstation 5000/125:  when using X11,          x)  Modem
101                                  set console=g or similar          x)  PCI bridge/bus?
102                          x)  DECstation 5840? "xbi-based SMP"          x)  Maple bus:
103                  o)  SGI and ARC machines (sgimips, arc):                  x)  Correct controller input
104                          x)  IP32 ("O2"): (Lots of stuff)                  x)  Mouse input
105                                  +)  mec (ethernet)          x)  Software emulation of BIOS calls:
106                                  +)  pci                  x)  GD-ROM emulation: Use the GDROM device.
107                                  +)  ahc (scsi)                  x)  Use the VGA font as a fake ROM font. (Better than
108                                  +)  ps2 kbd                      nothing.)
109                                  +)  memory controller          x)  Make as many as possible of the KOS examples run!
110                                  +)  framebuffer/graphics          x)  More homebrew demos/games.
111                                  +)  caches          x)  SPU: Sound emulation (ARM cpu).
112                          x)  more ARCBIOS stuff          x)  VME processor emulation? "(Sanyo LC8670 "Potato")" according to
113                          x)  Memory/interrupt controllers              Wikipedia, LC86K87 according to Comstedt's page. See
114                          x)  IP30 (Linux with graphics support?)              http://www.maushammer.com/vmu.html for a good description of
115                          x)  SMP / NUMA?  (SGI and various ARC machines)              the differences between LC86104C and the one used in the VME.
116                  o)  Playstation 2:  
117                          Hardware:  OHCI usb controller, keyboard, ...  Alpha:
118                  o)  Less interesting platforms:          x)  OSF1 PALcode, Virtual memory support.
119                          o)  newsmips:          x)  PALcode replacement! PAL1E etc opcodes...?
120                                  o)  NetBSD/newsmips, get it to detect a "real"          x)  Interrupt/exception/trap handling.
121                                      model, right now everything is 100% bogus          x)  Floating point exception correctness.
122                          o)  mipsco? (NetBSD)          x)  More work on bootup memory and register contents.
123                          o)  wgrisc? (big endian R3000, in OpenBSD's attic)          x)  More Alpha machine types, so it could work with
124                          o)  other embedded / evaluation MIPS boards              OpenBSD, FreeBSD, and Linux too?
125                          o)  Playstation 1? R3000A. Weird hardware?  
126                                  No FPU, but something as coproc 2.  SPARC (both the ISA and the machines):
127                          o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp          o)  Implement Adress space identifiers; load/stores etc.
128                                  (R4300, 4MB RAM, really weird memory map)          o)  Exception/trap/interrupt handling.
129            o)  Save/restore register windows etc! Both v9 and pre-v9!
130          File/disk handling:          o)  Finish the subcc and addcc flag computation code.
131                  o)  Read function argument count and types from binaries? (ELF?)          o)  Add more registers (floating point, control regs etc)
132                  o)  Better handling of tape files          o)  Disassemly of some more instructions?
133            o)  Are sll etc 32-bit sign-extending or zero-extending?
134          Userland ABI emulation:          o)  Floating point exception correctness.
135                  o)  see src/useremul.c          o)  SPARC v8, v7 etc?
136            o)  More machine modes and devices.
137          Terminal based interactive debugger:  
138                  o)  see src/debugger.c  POWER/PowerPC:
139            x)  Fix DECR timer speed, so it matches the host.
140          Terminal/console stuff:          x)  NetBSD/prep 3.x triggers a possible bug in the emulator:
141                  o)  allow emulated serial ports to be connected to the outside              <wdc_exec_command(0xd005e514,0xd60cdd30,0,8,..)>
142                      world in a more generic way, or even to other emulated                <ata_get_xfer(0,0xd60cdd30,0,8,..)>
143                      machines(!)                  <0x26c550(&ata_xfer_pool,2,0,8,..)>
144                    <0x35c71c(0x3f27000,0,52,8,..)>
145          Regression tests:  (Should be totally rewritten.)                <ata_exec_xfer(0xd005e4c8,0x3f27000,0,13,..)>
146                  o)  see tests/                  <atastart(0xd005e4c8,0x3f27000,0,13,..)>
147                      <__wdccommand_start(0xd005e4c8,0x3f27000,0,13,..)>
148          Save state of the whole emulated machine, to be able to load it back                      <bsw1(&prep_isa_io_space_tag,0x800001f6,0,176,..)>
149                  in later?  (Memory, all device's states, all registers and                  [ wdc: write to SDH: 0xb0 (sectorsize 2, lba=1, drive 1, head 0) ]
150                  so on.  Like taking a snapshot. (SimOS seems to do this,                      <wdcwait(0xd005e4c8,72,64,0xbb8,..)>
151                  according to its website.))                        <0x198120(0xd005e4c8,72,64,0xbb8,..)>
152                            <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
153          Better X-windows functionality:                          <delay(100,0,0,0xbb8,..)>
154                  o)  CLEAN UP the ugly event code              Note: <bsr1(&prep_isa_io_space_tag,0,0,0xbb8,..)>
155                  o)  Mouse clicks can be "missed" in the current system; this is          x)  PPC optimizations; instr combs
156                      not good. They should be put on a stack of some kind.          x)  64-bit stuff: either Linux on G5, or perhaps some hobbyist
157                  o)  More 2D and 3D framebuffer acceleration.                  version of AIX? (if there exists such a thing)
158                  o)  Non-resizable windows?  Or choose scaledown depending          x)  macppc: adb controller; keyboard (for framebuffer mode)
159                          on size (and center the image, with a black border).          x)  make OpenBSD/macppc work (PCI controller stuff)
160                  o)  Different scaledown on different windows?          x)  Floating point exception correctness.
161                  o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)          x)  Alignment exceptions.
162                  o)  Keyboard and mouse events:  
163                          x)  Do this for more machines than just DECstation  PReP:
164                          x)  more X11 cursor keycodes          x)  Clock time! ("Bad battery blah blah")
165                          x)  Keys like CTRL, ALT, SHIFT do not get through  
166                              by themselves (these are necessary for example  Algor:
167                              to change the font of an xterm in X in the          o)  Other models than the P5064?
168                              emulator)          o)  PCI interrupts... needed for stuff like the tlp NIC?
169                  o)  Generalize the framebuffer stuff by moving _ALL_ X11  
170                          specific code to src/x11.c!  BeBox:
171            o)  Interrupts. There seems to be a problem with WDC interrupts
172          Statistics:  (this could be interesting)              "after a short while", although a few interrupts get through?
173                  o)  Save to file and show graphics. It should be possible to          o)  Perhaps find a copy of BeOS and try it?
174                      run gxemul after a simulation to just show the graphics,  
175                      or convert to a .ppm or .tga or similar.  HPCmips:
176                  o)  memory accesses (to measure cache efficiency and          x)  Mouse/pad support! :)
177                          page coloring efficiency)          x)  A NIC? (As a PCMCIA device?)
178                  o)  nr of simultaneous ASIDs in use in the TLB, for MIPS  
179                  o)  percentage of time spent in different "states", such as  ARM:
180                      running userland code, kernel code, or idling (for CPUs          o)  See netwinder_reset() in NetBSD; the current "an internal error
181                      that have such an instruction, or whenever the PC is              occured" message after reboot/halt is too ugly.
182                      inside a specific idle-function (address range)).          o)  Generic ARM "wait"-like instruction?
183                      Possible additional state (for example on R3000): caches          o)  try to get netbsd/evbarm 3.x or 4.x running (iq80321)
184                      disabled.          o)  make the xscale counter registers (ccnt) work
185                  o)  position of read/write on (SCSI) disks          o)  make the ata controller usable for FreeBSD!
186            o)  Debian/cats crashes because of unimplemented coproc stuff.
187                fix this?
188    
189    Test machines:
190            o)  dev_fb block fill and copy
191            o)  dev_fb draw characters (from the built-in font)?
192            o)  dev_fb input device? mouse pointer coordinates and buttons
193                    (allow changes in these to cause interrupts as well?)
194            o)  Redefine the halt() function so that it stops "sometimes
195                soon", i.e. usage in demo code should be:
196                    for (;;) {
197                            halt();
198                    }
199    
200    Debugger:
201            o)  How does SMP debugging work? Does it simply use "threads"?
202                What if the guest OS (running on an emulated SMP machine)
203                has a usertask running, with userland threads?
204            o)  Try to make the debugger more modular and, if possible, reentrant!
205            o)  Remove the emul command? (But show network info if showing
206                machines?)
207            o)  Memory dumps should be able to dump both physical and
208                virtual emulated memory.
209            o)  Evaluate expressions within []? That would allow stuff like
210                cpu[x] where x is an expression.
211            o)  "pc = pc + 4" doesn't work! Bug. Should work. ("pc=pc+4" works.)
212            o)  Settings:
213                    x)  Special handlers for Write!
214                            +)  MIPS coproc regs
215                            +)  Alpha/MIPS/SPARC zero registers
216                            +)  x86 64/32/16-bit registers
217                    x)  Value formatter for resulting output.
218            o)  Call stack display (back-trace) of emulated programs.
219            o)  Nicer looking output of register dumps, floating point registers,
220                etc. Warn about weird/invalid register contents.
221            o)  Ctrl-C doesn't enter the debugger on some OSes (HP-UX?)...
222    
223    Dyntrans:
224            x)  For 32-bit emulation modes, that have emulated TLBs: tlbindex
225                arrays of mapped pages? Things to think about:
226                    x)  Only 32-bit mode! (64-bit => too much code)
227                    x)  One array for global pages, and one array _PER ASID_,
228                        for those archs that support that. On M88K, there should
229                        be one array for userspace, and one for supervisor, etc.
230                    x)  Larger-than-4K-pages must fill several bits in the array.
231                    x)  No TLB search will be necessary.
232                    x)  Total host space used, for 4 KB pages: 1 MB per table,
233                        i.e. 65 MB for 32-bit MIPS, 2 MB for M88K, if one byte
234                        is used as the tlb index.
235                    x)  (The index is actually +1, so that 0 means no hit.)
236            x)  "Merge" the cur_physpage and cur_ic_page variables/pointers to
237                one? I.e. change cur_ic_page to cur_physpage.ic_page or something.
238            x)  Instruction combination collisions? How to avoid easily...
239            x)  Think about how to do both SHmedia and SHcompact in a reasonable
240                way! (Or AMD64 long/protected/real, for that matter.)
241            x)  68K emulation; think about how to do variable instruction
242                lengths across page boundaries.
243            x)  Dyntrans with valgrind-inspired memory checker. (In memory_rw,
244                it would be reasonably simple to add; in each individual fast
245                load/store routine = a lot more work, and it would become
246                kludgy very fast.)
247            x)  Dyntrans with SMP... lots of work to be done here.
248            x)  Dyntrans with cache emulation... lots of work here as well.
249            x)  Remove the concept of base RAM completely; it would be more
250                generic to allow RAM devices to be used "anywhere".
251            o)  dev_mp doesn't work well with dyntrans yet
252            o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
253            x)  Redesign/rethink the delay slot mechanism used for e.g. MIPS,
254                    so that it caches a translation (that is, an instruction
255                    word and the instr_call it was translated to the last
256                    time), so that it doesn't need to do slow
257                    to_be_translated for each end of page?
258            x)  Program Counter statistics:
259                    Per machine? What about SMP? All data to the same file?
260                    A debugger command should be possible to use to enable/
261                    disable statistics gathering.
262                    Configuration file option!
263            x)  Breakpoints:
264                    o) Physical vs virtual addresses!
265                    o) 32-bit vs 64-bit sign extension for MIPS, and others?
266            x)  INVALIDATION should cause translations in _all_ cpus to be
267                invalidated, e.g. on a write to a write-protected page
268                (containing code)
269            x)  16-bit encodings? (MIPS16, ARM Thumb, 32-bit SH on SH64)
270            x)  Lots of other stuff: see src/cpus/README_DYNTRANS
271            x)  Native code generation backends:
272                    o)  calculate at runtime whether or not chunks of emulated
273                        (physical) memory are worth translating to native code
274                        (it is assumed that it has high overhead)
275                    o)  experiment with calling the host's cc and ld externally;
276                        extremely high overhead, but could be interesting none-
277                        theless.
278                    o)  experiment with using LLVM, or GNU Lightning?
279                    o)  Important cases to think about:
280                            x)  loads/stores
281                            x)  delay branches
282                            x)  other kinds of calls, branches
283                    o)  branches to already translated code blocks can
284                        link the blocks together (block-chaining), although
285                        I'll probably want to wait with this until other
286                        things work.
287                    o)  The first tests should be done with "testm88k", because
288                        that does not affect other modes.
289    
290    -------------------------------------------------------------------------------
291    
292    Performance comparison when emulating the QEMU_MIPS machine (QEMU's default
293    MIPS machine mode):
294    
295    mips-test-0.2:
296    --------------
297    
298    1. while true; do ls -l > /dev/null; echo -n .; done, 80x36 dots
299    2. while true; do /usr/bin/md5sum /usr/bin/* > /dev/null; echo -n .; done, 80 dots
300    3. while true; do grep hej lib/libc.so.6  > /dev/null; echo -n .; done, 80 dots
301    
302                            Test 1          Test 2          Test 3
303                            ------          ------          ------
304    QEMU 0.9.0:             2 min 20 sec    45 sec          4 min 41 seconds
305    GXemul-20070608:        1 min 59 sec    3 min 18 sec    18 min 10 seconds  [A]
306    
307    
308    [A] = Normal portable dyntrans, no native code generation.
309    
310    -------------------------------------------------------------------------------
311    
312    
313    Simple Valgrind-like checks?
314            o)  Mark every address with bits which tell whether or not the address
315                has been written to.
316            o)  What should happen when programs are loaded?  Text/data, bss (zero
317                filled). But stack space and heap is uninitialized.
318            o)  Uninitialized local variables:
319                    A load from a place on the stack which has not previously
320                    been stored to => warning. Increasing the stack pointer using
321                    any available means should reset the memory to uninitialized.
322            o)  If calls to malloc() and free() can be intercepted:
323                    o)  Access to a memory area after free() => warning.
324                    o)  Memory returned by malloc() is marked as not-initialized.
325                    o)  Non-passive, but good to have: Change the argument
326                        given to malloc, to return a slightly larger memory
327                        area, i.e.  margin_before + size + margin_after,
328                        and return the pointer  + margin_before.
329                        Any access to the margin_before or _after space results
330                        in warnings. (free() must be modified to free the
331                        actually allocated address.)
332    
333    Better CD Image file support:
334            x)  Support CD formats that contain more than 1 track, e.g.
335                CDI files (?). These can then contain a mixture of e.g. sound
336                and data tracks, and booting from an ISO filesystem path
337                would boot from [by default] the first data track.
338                (This would make sense for e.g. Dreamcast CD images, or
339                possibly other live-CD formats.)
340    
341    Networking:
342            x)  Redesign of the networking subsystem, at least the NAT translation
343                    part. The current way of allowing raw ethernet frames to be
344                    transfered to/from the emulator via UDP should probably be
345                    extended to allow the frames to be transmitted other ways as
346                    well.
347            x)  Also adding support for connecting ttys (either to xterms, or to
348                    pipes/sockets etc, or even to PPP->NAT or SLIP->NAT :-).
349            x)  Documentation updates (!) are very important, making it easier to
350                    use the (already existing) network emulation features.
351            x)  Fix performance problems caused by only allowing a
352                single TCP packet to be unacked.
353            x)  Don't hardcode offsets into packets!
354            x)  Test with lower than 100 max tcp/udp connections,
355                to make sure that reuse works!
356            x)  Make OpenBSD work better as a guest OS!
357            x)  DHCP? Debian doesn't actually send DHCP packets, even
358                    though it claims to? So it is hard to test.
359            x)  Multiple networks per emulation, and let different
360                NICs in machines connect to different networks.
361            x)  Support VDE (vde.sf.net)? Easiest/cleanest (before a
362                redesign of the network framework has been done) is
363                probably to connect it using the current (udp) solution.
364            x)  Allow SLIP connections, possibly PPP, in addition to
365                ethernet?
366    
367    Cache simulation:
368            o)  Command line flags for:
369                    o)  CPU endianness?
370                    o)  Cache sizes? (multiple levels)
371            o)  Separate from the CPU concept, so that multi-core CPUs sharing
372                e.g. a L2 cache can be simulated (?)
373            o)  Instruction cache emulation is easiest (if separate from the
374                data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
375                NOTE: if the architecture has a delay slot, then an instruction
376                slot can actually be executed as 2 instructions.
377            o)  Data cache emulation = harder; each arch's load/store routines
378                must include support? running one instruction at a time and
379                having a cpu-dependant lookup function for each instruction
380                is another option (easier to implement, but very very slow).
381    
382    Documentation:
383            x)  Update the documentation regarding the testmachine interrupts.
384            x)  Note about sandboxing/security:
385                    Not all emulated instructions fail in the way they would
386                    do on real hardware (e.g. a userspace program writing to
387                    a system register might work in GXemul, but it would
388                    fail on real hardware).  Sandbox = contain from the
389                    host OS. But the emulated programs will run "less
390                    securely".
391            x)  Try NetBSD/arc 4.x! (It seems to work with disk images!)
392            x)  NetBSD/pmax 4 install instructions: xterm instead of vt100!
393            x)  BETTER DEVICE EXAMPLES!
394                    o)  Move away from technical.html to somewhere new.
395                    o)  DEVICE_TICK
396                    o)  Implement example devices using interrupts, dyntrans
397                        memory access, etc.?
398            x)  Document the dyntrans core?
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            x)  Better description on how to set up a cross compiler?
408                Example for MIPS64.
409            o)  Automagic documentation generation?
410                    x)  machines, cpus, devices.
411                    x)  REMEMBER that several machines/devices can be in
412                            the same source file!
413            o)  Try to rewrite the install instructions for those machines
414                that use 3MAX into using CATS or hpcmips? (To remove the need
415                to use a raw ffs partition, using up all of the disk image.)
416    
417    The Device subsystem:
418            x)  allow devices to be moved and/or changed in size (down to a
419                minimum size, etc, or up to a max size); if there is a collision,
420                return false. It is up to the caller to handle this situation!
421            x)  NOTE: Translations must be invalidated, both for
422                registering new devices, and for moving existing ones.
423                cpu->invalidate translation caches, for all CPUs that
424                are connected to a specific memory.
425            x)  keep track of interrupts and busses? actually, allowing any device
426                to be a bus might be a nice idea.
427            x)  turn interrupt controllers into devices? :-)
428            x)  refactor various clocks/nvram/cmos into one device?
429    
430    PCI:
431            x)  Pretty much everything related to runtime configuration, device
432                slots, interrupts, etc must be redesigned/cleaned up. The current
433                code is very hardcoded and ugly.
434            o)  Allow cards to be added/removed during runtime more easily.
435            o)  Allow cards to be enabled/disabled (i/o ports, etc, like
436                NetBSD needs for disk controller detection).
437            o)  Allow devices to be moved in memory during runtime.
438            o)  Interrupts per PCI slot, etc. (A-D).
439            o)  PCI interrupt controller logic... very hard to get right,
440                because these differ a lot from one machine to the next.
441            x)  last write was ffffffff ==> fix this, it should be used
442                together with a mask to get the correct bits. also, not ALL
443                bits are size bits! (lowest 4 vs lowest 2?)
444            x)  add support for address fixups
445            x)  generalize the interrupt routing stuff (lines etc)
446    
447    Clocks and timers:
448            x)  Fix the PowerPC DECR interrupt speed! (MacPPC and PReP speed, etc.)
449            x)  DON'T HARDCODE 100 HZ IN cpu_mips_coproc.c!
450            x)  NetWinder timeofday is incorrect! Huh? grep -R for ta_rtc_read in
451                NetBSD sources; it doesn't seem to be initialized _AT ALL_?!
452            x)  Cobalt TOD is incorrect!
453            x)  Go through all other machines, one by one, and fix them.
454    
455    Config file parser:
456            o)  Rewrite it from scratch!
457            o)  Usage of any expression available through the debugger
458            o)  Allow interrupt controllers to be added! and interrupts
459                to be used in more ways than before
460            o)  Support for running debugger commands (like the -c
461                command line option)
462    
463    Floating point layer:
464            o)  make it common enough to be used by _all_ emulation modes
465            o)  implement correct error/exception handling and rounding modes
466            o)  implement more helper functions (i.e. add, sub, mul...)
467            o)  non-IEEE modes (i.e. x86)?
468    
469    Userland emulation:
470            x)  Try to prefix "/emul/mips/" or similar to all filenames,
471                and only if that fails, try the given filename.
472                Read this setting from an environment variable, and only
473                if there is none, fall back to hardcoded string.
474            x)  File descriptor (0,1,2) assumptions? Find and fix these?
475            x)  Dynamic linking!
476            x)  Lots of stuff; freebsd, netbsd, linux, ... syscalls.
477            x)  Initial register/stack contents (environment, command line args).
478            x)  Return value (from main).
479            x)  mmap emulation layer
480            x)  errno emulation layer
481            x)  struct conversions for many syscalls
482    
483    Sound:
484            x)  generic sound framework
485            x)  add one or more sound cards as devices; add a testmachine
486                sound card first?
487            x)  Dreamcast sound? Generic PCI sound cards?
488    
489    ASC SCSI controller:
490            x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
491                cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
492                in NetBSD itself, http://mail-index.netbsd.org/source-changes/
493                2005/11/06/0024.html suggests that.)
494                NetBSD 4.x seems to work? :)
495    
496    Caches / memory hierarchies: (this is mostly MIPS-specific)
497            o)  src/memory*.c: Implement correct cache emulation for
498                all CPU types. (currently only R2000/R3000 is implemented)
499                (per CPU, multiple levels should be possible, associativity etc!)
500            o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
501            o)  Move the -S (fill mem with random) functionality into the
502                memory.c subsystem, not machine.c or wherever it is now
503            o)  ECC stuff, simulation of memory errors?  (Machine dependent)
504            o)  More than 4GB of emulated RAM, when run on a 32-bit host?
505                (using manual swap-out of blocks to disk, ugly)
506            o)  A global command line option should be used to turn
507                cache emulation on or off. When off, caches should be
508                faked like they are right now. When on, caches and
509                memory latencies should be emulated as correctly as
510                possible.
511    
512    File/disk/symbol handling:
513            o)  Make sure that disks can be added/removed during runtime!
514                (Perhaps this needs a reasonably large re-write.)
515            o)  Remove some of the complexity in file format guessing, for
516                    Ultrix kernels that are actually disk images?
517            o)  Better handling of tape files      
518            o)  Read function argument count and types from binaries? (ELF?)
519            o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
520                Microsoft's C++, so multiple schemes must be possible. See
521                URL at top of src/symbol_demangle.c for more info.
522    
523    Userland ABI emulation:
524            o)  see src/useremul.c
525    
526    Better framebuffer and X-windows functionality:
527            o)  Generalize the update_x1y1x2y2 stuff to an extend-region()
528                function...
529            o)  -Yx sometimes causes crashes.
530            o)  Simple device access to framebuffer_blockcopyfill() etc,
531                and text output (using the built-in fonts), for dev_fb.
532            o)  CLEAN UP the ugly event code
533            o)  Mouse clicks can be "missed" in the current system; this is
534                not good. They should be put on a stack of some kind.
535            o)  More 2D and 3D framebuffer acceleration.
536            o)  Non-resizable windows?  Or choose scaledown depending
537                    on size (and center the image, with a black border).
538            o)  Different scaledown on different windows?
539            o)  Non-integral scale-up? (E.g. 640x480 -> 1024x768)
540            o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
541            o)  Bug reported by Elijah Rutschman on MacOS with weird
542                keys (F5 = cursor down?).
543            o)  Keyboard and mouse events:
544                    x)  Do this for more machines than just DECstation
545                    x)  more X11 cursor keycodes
546                    x)  Keys like CTRL, ALT, SHIFT do not get through
547                        by themselves (these are necessary for example
548                        to change the font of an xterm in X in the
549                        emulator)
550            o)  Generalize the framebuffer stuff by moving _ALL_ X11
551                    specific code to src/x11.c!
552    
553    -------------------------------------------------------------------------------
554    

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