Annotation of /trunk/TODO

$Id: TODO,v 1.298 2006/06/25 11:08:04 debug Exp $

Hm. This file is in random order, and not all parts of it are up-to-date.

--------------

        x)  FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
        x)  Find a way to get rid of the cpu_create_or_reset_tc in the
            R2000/R3000 cache isolation code. (NetBSD works without it,
            but not Ultrix and Linux yet.)
        x)  Formalize the statistics gathering stuff for dyntrans...
        x)  ... and use it to optimize MIPS dyntrans stuff.
        x)  Clock framework? Go through all clock devices, make sure they
            return correct data, and run at correct speeds!
        x)  Optimizations, continuing on 64-bit issues etc with dyntrans
        x)  Dyntrans with SMP... lots of work to be done here.
        x)  Dyntrans with cache emulation... lots of work here as well.
        x)  Actually use the settings object, better debugger stuff, etc.
        x)  Wait for new releases of NetBSD, and test with those.

--------------

SMP:
        o)  dev_mp doesn't work well with dyntrans yet
        o)  In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans

MIPS:
        o)  Fix invalidate_asid so it works well for non-R3000 too!
        x)  [Re]add an interrupt-asserted bit for MIPS, to speed up
            interrupt handling slightly?
        +)  Print a warning on the first reserved instruction.
        +)  Some more work on opcodes.
                x) MIPS64 revision 2.
                x) _MAYBE_ TX79 and R5900 actually differ in their
                   opcodes? Check this carefully!
        o)  Dyntrans: Count register updates are probably not 100% correct yet.
        o)  Dyntrans: SMP correctness
        o)  Refactor code for performance and readability/maintainability.
        o)  Instruction combinations? Possible candidates (but profile first!):
                o)  multiple loads/stores in a row
                o)  strlen, memset loops etc
                o)  compare + branch
        o)  DROTR32 and similar MIPS64 rev 2 instructions, which have
            a rotation bit which differs from previous ISAs.
        o)  EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
            _NOT_ the same as for R5900!
        o)  R4000 and others:
                x)  watchhi/watchlo exceptions, and other exception
                    handling details
        o)  R10000 and others:  (R12000, R14000 ?)
                x)  memory space, exceptions, ...
                x)  use cop0 framemask for tlb lookups
                    (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)

Dyntrans:
        x)  Move the mips_init_64bit_dummy_tables() etc calls into
            src/cpu.c, for all 64-bit cpus?
        x)  64-bit "phystranslation" lookup as in 32-bit mode? Would probably
                help performance a bit.
        x)  Common fatal_abort() function, which drops into the debugger
                without continuing.
        x)  INVALIDATION should cause translations in _all_ cpus to be
            invalidated, e.g. on a write to a write-protected page
            (containing code)
        x)  better (formally defined) instr call statistics (-s command
            line option?), multiple different types? (virtual pc, physical pc)
        x)  Call/return hints?
        x)  16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
        x)  H8?
        x)  Lots of other stuff: see src/cpus/README_DYNTRANS
        x)  true recompilation backend? think carefully about this,
            experiment in a separate project (not in GXemul)
        x)  Remove the dyntrans_alignment_check functionality; although
            it gives slightly higher peformance sometimes, it increases
            the complexity of the code too much!

Alpha:
        o)  Virtual memory (tlbs etc)
        o)  Get {NetBSD,OpenBSD,Linux}/alpha booting. :)

SPARC:
        o)  Add all registers (floating point, control regs etc)
        o)  Save/restore register windows etc!
        o)  Disassemly of some more instructions.
        o)  Are sll etc 32-bit sign-extending or zero-extending?
        o)  Finish the cmp (subcc) flag computation code.
        o)  Finish the GDB register stuff.

Debugger:
        o)  How does SMP debugging work? Does it simply use "threads"?
                What if the guest OS (running on an emulated SMP machine)
                has a usertask running, with userland threads?
        o)  Try to make the debugger more modular and, if possible, reentrant!
        o)  Remove the emul command? (But show network info if showing
                machines?)
        o)  Generalize the expression evaluator. (debugger_expr.c?)
                settable variables      ("show nr of instructions on average")
                emul[x]                 defaults to current emul
                machine[x]              defaults to current machine
                cpu[x]                  defaults to currently focused cpu
                registers               cpu arch dependent (#-prefix)
                symbols                 @-prefix
                numeric constants       decimal, hex, and octal ($-prefix)
                boolean                 yes,no, true,false
                operators (+ - * / % & | ^ !)
                parentheses for grouping subexpressions
                NOTE: the change from % to # for register prefix!
                examples:
                                emul[0].machine[2].cpu[0].pc
                                machine[test2].cpu[1].ra = main
                                settings.show_trace_tree = yes

                Settings:
                        o)  Remove a setting.
                        o)  Read/write a setting given a name. (Read as
                            string and/or int64_t simultaneously?)

                Help command should have subsections! One for "expressions",
                mirrored in the documentation, but the internal help should
                be the one that should be considered correct.
        o)  see src/debugger.c for more

POWER/PowerPC:
        x)  PPC optimizations; instr combs
        x)  64-bit stuff
        x)  find and fix the bug which causes NetBSD/macppc to fail after
            an install!
        x)  macppc: adb controller; keyboard (for framebuffer mode)
        x)  make OpenBSD/macppc work (PCI controller stuff)

Algor:
        PCI and ISA and LOCAL interrupts! --> wdc could start working
        Add interrupt controller in dev_algor.c.

ARM:
        o)  try to get netbsd/evbarm 3.x running (iq80321)
        o)  make the xscale counter registers (ccnt) work
        o)  make the ata controller usable for FreeBSD!
        o)  zaurus for openbsd...
        o)  debian/cats crashes because of unimplemented coproc stuff.
            fix this?

Cache simulation:
        o)  Separate from the CPU concept, so that multi-core CPUs sharing
            e.g. a L2 cache can be simulated (?)
        o)  Instruction cache emulation is easiest (if separate from the
            data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
            NOTE: if the architecture has a delay slot, then an instruction
            slot can actually be executed as 2 instructions.
        o)  Data cache emulation = harder; each arch's load/store routines
            must include support? running one instruction at a time and
            having a cpu-dependant lookup function for each instruction
            is another option (easier to implement, but very very slow).

Documentation:
        o)  machines, cpus, devices.
        o)  Automagic documentation generation:
                x)  REMEMBER that several machines/devices can be in
                        the same source file!
        o)  Try to rewrite the install instructions for those machines
            that use 3MAX into using CATS? (To remove the need to a raw
            ffs partition using up all of the disk image.)

More generic out_of_memory error reporting, and check everywhere!
        Causes: OpenBSD has low default limits for normal users.
                Host is 32-bit? (32-bit hosts are limited to 4 GB or less
                of userspace memory.)
                You are actually low on RAM. (As trivial as this might sound,
                Unix systems usually allow processes to allocate virtual
                memory beyond the amount of RAM in the machine.)

Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc.
        Use the debugger's symbolic name stuff. (which will have to be
        extended soon to support stuff like  "2*x + symbol + y" etc. cool
        stuff)

Sprite (guest OS for DECstation emulation)
        x)  Timing problems during bootup?

The Device subsystem:
        x)  allow devices to be moved and/or changed in size (down to a
            minimum size, etc, or up to a max size)
        x)  keep track of interrupts and busses? actually, allowing any device
            to be a bus might be a nice idea.
        x)  turn interrupt controllers into devices? :-)
        x)  refactor various clocks/nvram/cmos into one device?

Clocks:
        x)  General framework for automagic clock adjustment for _all_
            kinds of clocks and timers. (Which should be possible to turn
            off, of course, like the way DECstation emulation works now.)

PCI:
        x)  last write was ffffffff ==> fix this, it should be used
            together with a mask to get the correct bits. also, not ALL
            bits are size bits! (lowest 4 vs lowest 2?)
        x)  add support for address fixups
        x)  generalize the interrupt routing stuff (lines etc). this should
            be per machine? or per bus, that's better
        x)  add a "pcn" NIC (AMD PCnet32 Lance 79c970 (PCI 1022:2000)),
            could be useful for several machine modes (Malta, Algor, evbarm,
            hp700?, macppc, etc.)

Network layer:
        o)  DHCP (for Debian and BSD installers :-)
        o)  increase performance
        o)  don't rely on NetBSD-ish usage
        o)  Multiple networks per emulation, and let different
            NICs in machines connect to different networks.
        o)  many other issues: see src/net.c

Busses:
        o)  Redesign the entire "mainbus" concept!
        o)  Busses should be placed in a hierarchical tree!
        o)  Easily configurable interrupt routing in SMP systems.
        o)  Specific clock/bus speeds, cpu speeds etc.
        o)  Synchronization over network? or at least in dyntrans within
            one emulated machine
        o)  dev->bus: TurboChannel, PCMCIA, ADB?

Config file parser:
        o)  Rewrite it from scratch!
        o)  Usage of any expression available through the debugger
        o)  Support for running debugger commands (like the -c
            command line option)

Floating point layer:
        o)  make it common enough to be used by _all_ emulation modes
        o)  implement more stuff
        o)  non-IEEE modes (i.e. x86)?

Userland emulation:
        x)  Lots of stuff; freebsd and netbsd (and linux?) syscalls.
        x)  Dynamic linking? Hm.

Sound:
        x)  generic sound framework
        x)  add one or more sound cards as devices

ASC SCSI controller:
        x)  NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
            cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
            in NetBSD itself, http://mail-index.netbsd.org/source-changes/
            2005/11/06/0024.html suggests that.)

Caches / memory hierarchies: (this is mostly MIPS-specific)
        o)  MIPS coproc.c: bits in config registers should reflect
            correct cache sizes for _all_ CPU types. (currently only
            implemented for R4000, R1x000, and a few others)
        o)  src/memory*.c: Implement correct cache emulation for
            all CPU types. (currently only R2000/R3000 is implemented)
            (per CPU, multiple levels should be possible,
            associativity etc!)
        o)  R2000/R3000 isn't _100%_ correct, just almost correct :)
        o)  Move the -S (fill mem with random) functionality into the
            memory.c subsystem, not machine.c or wherever it is now
        o)  ECC stuff, simulation of memory errors?  (Machine dependent)
        o)  More than 4GB of emulated RAM, when run on a 32-bit host?
            (using manual swap-out of blocks to disk, ugly)
        o)  A global command line option should be used to turn
            cache emulation on or off. When off, caches should be
            faked like they are right now. When on, caches and
            memory latencies should be emulated as correctly as
            possible.

File/disk/symbol handling:
        o)  Better handling of tape files
        o)  Read function argument count and types from binaries? (ELF?)
        o)  Better demangling of C++ names. Note: GNU's C++ differs from e.g.
            Microsoft's C++, so multiple schemes must be possible. See
            URL at top of src/symbol_demangle.c for more info.

Userland ABI emulation:
        o)  see src/useremul.c

Terminal/console:
        o)  allow emulated serial ports to be connected to the outside
            world in a more generic way, or even to other emulated
            machines(?)

Save state of the whole emulated machine, to be able to load it back
        in later?  (Memory, all device's states, all registers and
        so on.  Like taking a snapshot. (SimOS seems to do this,
        according to its website.))

Better framebuffer and X-windows functionality:
        o)  -Yx sometimes causes crashes.
        o)  Simple device access to framebuffer_blockcopyfill() etc,
            and text output (using the built-in fonts), for dev_fb.
        o)  CLEAN UP the ugly event code
        o)  Mouse clicks can be "missed" in the current system; this is
            not good. They should be put on a stack of some kind.
        o)  More 2D and 3D framebuffer acceleration.
        o)  Non-resizable windows?  Or choose scaledown depending
                on size (and center the image, with a black border).
        o)  Different scaledown on different windows?
        o)  Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
        o)  Bug reported by Elijah Rutschman on MacOS with weird
            keys (F5 = cursor down?).
        o)  Keyboard and mouse events:
                x)  Do this for more machines than just DECstation
                x)  more X11 cursor keycodes
                x)  Keys like CTRL, ALT, SHIFT do not get through
                    by themselves (these are necessary for example
                    to change the font of an xterm in X in the
                    emulator)
        o)  Generalize the framebuffer stuff by moving _ALL_ X11
                specific code to src/x11.c!

Statistics:  (this could be interesting)
        o)  Save to file and show graphics. It should be possible to
            run gxemul after a simulation to just show the graphics,
            or convert to a .ppm or .tga or similar.
        o)  memory accesses (to measure cache efficiency and
                page coloring efficiency)
        o)  nr of simultaneous ASIDs in use in the TLB, for MIPS
        o)  percentage of time spent in different "states", such as
            running userland code, kernel code, or idling (for CPUs
            that have such an instruction, or whenever the PC is
            inside a specific idle-function (address range)).
            Possible additional state (for example on R3000): caches
            disabled.
        o)  position of read/write on (SCSI) disks

1	dpavlin	26	$Id: TODO,v 1.298 2006/06/25 11:08:04 debug Exp $
2	dpavlin	2
3	dpavlin	22	Hm. This file is in random order, and not all parts of it are up-to-date.
4	dpavlin	20
5	dpavlin	24	--------------
6	dpavlin	2
7	dpavlin	24	x) FIX THE NON-R3000 TRANSLATION CACHE INVALIDATION BOTTLENECKS!
8	dpavlin	26	x) Find a way to get rid of the cpu_create_or_reset_tc in the
9			R2000/R3000 cache isolation code. (NetBSD works without it,
10			but not Ultrix and Linux yet.)
11			x) Formalize the statistics gathering stuff for dyntrans...
12			x) ... and use it to optimize MIPS dyntrans stuff.
13	dpavlin	24	x) Clock framework? Go through all clock devices, make sure they
14			return correct data, and run at correct speeds!
15			x) Optimizations, continuing on 64-bit issues etc with dyntrans
16			x) Dyntrans with SMP... lots of work to be done here.
17			x) Dyntrans with cache emulation... lots of work here as well.
18			x) Actually use the settings object, better debugger stuff, etc.
19			x) Wait for new releases of NetBSD, and test with those.
20
21			--------------
22
23			SMP:
24			o) dev_mp doesn't work well with dyntrans yet
25			o) In general, IPIs, CAS, LL/SC etc must be made to work with dyntrans
26
27			MIPS:
28			o) Fix invalidate_asid so it works well for non-R3000 too!
29			x) [Re]add an interrupt-asserted bit for MIPS, to speed up
30			interrupt handling slightly?
31			+) Print a warning on the first reserved instruction.
32			+) Some more work on opcodes.
33			x) MIPS64 revision 2.
34			x) _MAYBE_ TX79 and R5900 actually differ in their
35			opcodes? Check this carefully!
36			o) Dyntrans: Count register updates are probably not 100% correct yet.
37			o) Dyntrans: SMP correctness
38			o) Refactor code for performance and readability/maintainability.
39			o) Instruction combinations? Possible candidates (but profile first!):
40			o) multiple loads/stores in a row
41			o) strlen, memset loops etc
42			o) compare + branch
43			o) DROTR32 and similar MIPS64 rev 2 instructions, which have
44			a rotation bit which differs from previous ISAs.
45			o) EI and DI instructions for MIPS64/32 rev 2. NOTE: These are
46			_NOT_ the same as for R5900!
47			o) R4000 and others:
48			x) watchhi/watchlo exceptions, and other exception
49			handling details
50			o) R10000 and others: (R12000, R14000 ?)
51			x) memory space, exceptions, ...
52			x) use cop0 framemask for tlb lookups
53			(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)
54
55	dpavlin	14	Dyntrans:
56	dpavlin	24	x) Move the mips_init_64bit_dummy_tables() etc calls into
57			src/cpu.c, for all 64-bit cpus?
58			x) 64-bit "phystranslation" lookup as in 32-bit mode? Would probably
59			help performance a bit.
60			x) Common fatal_abort() function, which drops into the debugger
61			without continuing.
62	dpavlin	22	x) INVALIDATION should cause translations in _all_ cpus to be
63			invalidated, e.g. on a write to a write-protected page
64			(containing code)
65	dpavlin	24	x) better (formally defined) instr call statistics (-s command
66			line option?), multiple different types? (virtual pc, physical pc)
67	dpavlin	22	x) Call/return hints?
68			x) 16-bit encodings? (MIPS16, ARM Thumb, SH3, ...)
69	dpavlin	24	x) H8?
70	dpavlin	18	x) Lots of other stuff: see src/cpus/README_DYNTRANS
71	dpavlin	22	x) true recompilation backend? think carefully about this,
72			experiment in a separate project (not in GXemul)
73	dpavlin	24	x) Remove the dyntrans_alignment_check functionality; although
74			it gives slightly higher peformance sometimes, it increases
75			the complexity of the code too much!
76	dpavlin	18
77	dpavlin	24	Alpha:
78			o) Virtual memory (tlbs etc)
79			o) Get {NetBSD,OpenBSD,Linux}/alpha booting. :)
80
81			SPARC:
82			o) Add all registers (floating point, control regs etc)
83			o) Save/restore register windows etc!
84			o) Disassemly of some more instructions.
85			o) Are sll etc 32-bit sign-extending or zero-extending?
86			o) Finish the cmp (subcc) flag computation code.
87			o) Finish the GDB register stuff.
88
89			Debugger:
90			o) How does SMP debugging work? Does it simply use "threads"?
91			What if the guest OS (running on an emulated SMP machine)
92			has a usertask running, with userland threads?
93			o) Try to make the debugger more modular and, if possible, reentrant!
94			o) Remove the emul command? (But show network info if showing
95			machines?)
96			o) Generalize the expression evaluator. (debugger_expr.c?)
97			settable variables ("show nr of instructions on average")
98			emul[x] defaults to current emul
99			machine[x] defaults to current machine
100			cpu[x] defaults to currently focused cpu
101			registers cpu arch dependent (#-prefix)
102			symbols @-prefix
103			numeric constants decimal, hex, and octal ($-prefix)
104			boolean yes,no, true,false
105			operators (+ - * / % & \| ^ !)
106			parentheses for grouping subexpressions
107			NOTE: the change from % to # for register prefix!
108			examples:
109			emul[0].machine[2].cpu[0].pc
110			machine[test2].cpu[1].ra = main
111			settings.show_trace_tree = yes
112
113			Settings:
114			o) Remove a setting.
115			o) Read/write a setting given a name. (Read as
116			string and/or int64_t simultaneously?)
117
118			Help command should have subsections! One for "expressions",
119			mirrored in the documentation, but the internal help should
120			be the one that should be considered correct.
121			o) see src/debugger.c for more
122
123			POWER/PowerPC:
124			x) PPC optimizations; instr combs
125			x) 64-bit stuff
126			x) find and fix the bug which causes NetBSD/macppc to fail after
127			an install!
128			x) macppc: adb controller; keyboard (for framebuffer mode)
129			x) make OpenBSD/macppc work (PCI controller stuff)
130
131			Algor:
132			PCI and ISA and LOCAL interrupts! --> wdc could start working
133			Add interrupt controller in dev_algor.c.
134
135			ARM:
136			o) try to get netbsd/evbarm 3.x running (iq80321)
137			o) make the xscale counter registers (ccnt) work
138			o) make the ata controller usable for FreeBSD!
139			o) zaurus for openbsd...
140			o) debian/cats crashes because of unimplemented coproc stuff.
141			fix this?
142
143			Cache simulation:
144			o) Separate from the CPU concept, so that multi-core CPUs sharing
145			e.g. a L2 cache can be simulated (?)
146			o) Instruction cache emulation is easiest (if separate from the
147			data cache); similar hack as the S;I; hack in cpu_dyntrans.c.
148			NOTE: if the architecture has a delay slot, then an instruction
149			slot can actually be executed as 2 instructions.
150			o) Data cache emulation = harder; each arch's load/store routines
151			must include support? running one instruction at a time and
152			having a cpu-dependant lookup function for each instruction
153			is another option (easier to implement, but very very slow).
154
155			Documentation:
156			o) machines, cpus, devices.
157			o) Automagic documentation generation:
158			x) REMEMBER that several machines/devices can be in
159			the same source file!
160			o) Try to rewrite the install instructions for those machines
161			that use 3MAX into using CATS? (To remove the need to a raw
162			ffs partition using up all of the disk image.)
163
164	dpavlin	22	More generic out_of_memory error reporting, and check everywhere!
165			Causes: OpenBSD has low default limits for normal users.
166			Host is 32-bit? (32-bit hosts are limited to 4 GB or less
167			of userspace memory.)
168			You are actually low on RAM. (As trivial as this might sound,
169			Unix systems usually allow processes to allocate virtual
170			memory beyond the amount of RAM in the machine.)
171
172			Breakpoints: 32-bit vs 64-bit sign extension for MIPS, warnings, etc.
173			Use the debugger's symbolic name stuff. (which will have to be
174			extended soon to support stuff like "2*x + symbol + y" etc. cool
175			stuff)
176
177			Sprite (guest OS for DECstation emulation)
178			x) Timing problems during bootup?
179
180			The Device subsystem:
181			x) allow devices to be moved and/or changed in size (down to a
182			minimum size, etc, or up to a max size)
183			x) keep track of interrupts and busses? actually, allowing any device
184	dpavlin	24	to be a bus might be a nice idea.
185			x) turn interrupt controllers into devices? :-)
186	dpavlin	22	x) refactor various clocks/nvram/cmos into one device?
187
188	dpavlin	24	Clocks:
189			x) General framework for automagic clock adjustment for _all_
190			kinds of clocks and timers. (Which should be possible to turn
191			off, of course, like the way DECstation emulation works now.)
192	dpavlin	22
193			PCI:
194	dpavlin	24	x) last write was ffffffff ==> fix this, it should be used
195			together with a mask to get the correct bits. also, not ALL
196			bits are size bits! (lowest 4 vs lowest 2?)
197	dpavlin	22	x) add support for address fixups
198			x) generalize the interrupt routing stuff (lines etc). this should
199			be per machine? or per bus, that's better
200	dpavlin	24	x) add a "pcn" NIC (AMD PCnet32 Lance 79c970 (PCI 1022:2000)),
201			could be useful for several machine modes (Malta, Algor, evbarm,
202			hp700?, macppc, etc.)
203	dpavlin	22
204			Network layer:
205			o) DHCP (for Debian and BSD installers :-)
206			o) increase performance
207			o) don't rely on NetBSD-ish usage
208			o) Multiple networks per emulation, and let different
209			NICs in machines connect to different networks.
210			o) many other issues: see src/net.c
211
212			Busses:
213			o) Redesign the entire "mainbus" concept!
214			o) Busses should be placed in a hierarchical tree!
215			o) Easily configurable interrupt routing in SMP systems.
216			o) Specific clock/bus speeds, cpu speeds etc.
217			o) Synchronization over network? or at least in dyntrans within
218			one emulated machine
219			o) dev->bus: TurboChannel, PCMCIA, ADB?
220
221			Config file parser:
222	dpavlin	24	o) Rewrite it from scratch!
223	dpavlin	22	o) Usage of any expression available through the debugger
224			o) Support for running debugger commands (like the -c
225			command line option)
226
227			Floating point layer:
228			o) make it common enough to be used by _all_ emulation modes
229	dpavlin	24	o) implement more stuff
230	dpavlin	22	o) non-IEEE modes (i.e. x86)?
231
232	dpavlin	14	Userland emulation:
233	dpavlin	22	x) Lots of stuff; freebsd and netbsd (and linux?) syscalls.
234	dpavlin	14	x) Dynamic linking? Hm.
235	dpavlin	12
236	dpavlin	22	Sound:
237			x) generic sound framework
238			x) add one or more sound cards as devices
239	dpavlin	12
240	dpavlin	24	ASC SCSI controller:
241			x) NetBSD/arc 2.0 uses the ASC controller in a way which GXemul
242			cannot yet handle. (NetBSD 1.6.2 works ok.) (Possibly a problem
243			in NetBSD itself, http://mail-index.netbsd.org/source-changes/
244			2005/11/06/0024.html suggests that.)
245
246	dpavlin	22	Caches / memory hierarchies: (this is mostly MIPS-specific)
247			o) MIPS coproc.c: bits in config registers should reflect
248			correct cache sizes for _all_ CPU types. (currently only
249			implemented for R4000, R1x000, and a few others)
250			o) src/memory*.c: Implement correct cache emulation for
251			all CPU types. (currently only R2000/R3000 is implemented)
252			(per CPU, multiple levels should be possible,
253			associativity etc!)
254			o) R2000/R3000 isn't _100%_ correct, just almost correct :)
255			o) Move the -S (fill mem with random) functionality into the
256			memory.c subsystem, not machine.c or wherever it is now
257			o) ECC stuff, simulation of memory errors? (Machine dependent)
258			o) More than 4GB of emulated RAM, when run on a 32-bit host?
259			(using manual swap-out of blocks to disk, ugly)
260			o) A global command line option should be used to turn
261			cache emulation on or off. When off, caches should be
262			faked like they are right now. When on, caches and
263			memory latencies should be emulated as correctly as
264			possible.
265	dpavlin	2
266	dpavlin	22	File/disk/symbol handling:
267			o) Better handling of tape files
268			o) Read function argument count and types from binaries? (ELF?)
269	dpavlin	24	o) Better demangling of C++ names. Note: GNU's C++ differs from e.g.
270			Microsoft's C++, so multiple schemes must be possible. See
271			URL at top of src/symbol_demangle.c for more info.
272	dpavlin	2
273	dpavlin	22	Userland ABI emulation:
274			o) see src/useremul.c
275	dpavlin	12
276	dpavlin	22	Terminal/console:
277			o) allow emulated serial ports to be connected to the outside
278			world in a more generic way, or even to other emulated
279			machines(?)
280	dpavlin	2
281	dpavlin	22	Save state of the whole emulated machine, to be able to load it back
282			in later? (Memory, all device's states, all registers and
283			so on. Like taking a snapshot. (SimOS seems to do this,
284			according to its website.))
285	dpavlin	6
286	dpavlin	22	Better framebuffer and X-windows functionality:
287			o) -Yx sometimes causes crashes.
288			o) Simple device access to framebuffer_blockcopyfill() etc,
289			and text output (using the built-in fonts), for dev_fb.
290			o) CLEAN UP the ugly event code
291			o) Mouse clicks can be "missed" in the current system; this is
292			not good. They should be put on a stack of some kind.
293			o) More 2D and 3D framebuffer acceleration.
294			o) Non-resizable windows? Or choose scaledown depending
295			on size (and center the image, with a black border).
296			o) Different scaledown on different windows?
297			o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
298	dpavlin	24	o) Bug reported by Elijah Rutschman on MacOS with weird
299			keys (F5 = cursor down?).
300	dpavlin	22	o) Keyboard and mouse events:
301			x) Do this for more machines than just DECstation
302			x) more X11 cursor keycodes
303			x) Keys like CTRL, ALT, SHIFT do not get through
304			by themselves (these are necessary for example
305			to change the font of an xterm in X in the
306			emulator)
307			o) Generalize the framebuffer stuff by moving _ALL_ X11
308			specific code to src/x11.c!
309	dpavlin	2
310	dpavlin	22	Statistics: (this could be interesting)
311			o) Save to file and show graphics. It should be possible to
312			run gxemul after a simulation to just show the graphics,
313			or convert to a .ppm or .tga or similar.
314			o) memory accesses (to measure cache efficiency and
315			page coloring efficiency)
316			o) nr of simultaneous ASIDs in use in the TLB, for MIPS
317			o) percentage of time spent in different "states", such as
318			running userland code, kernel code, or idling (for CPUs
319			that have such an instruction, or whenever the PC is
320			inside a specific idle-function (address range)).
321			Possible additional state (for example on R3000): caches
322			disabled.
323			o) position of read/write on (SCSI) disks
324	dpavlin	2