upstream/0.3.1/TODO

$Id: TODO,v 1.125 2005/03/06 08:21:10 debug Exp $

Here's a short list of what I have left to do on GXemul. This file is a mess.
Order is random. Don't trust it to be up-to-date.


        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 dependant)
                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.

        Network layer:
                o)  Multiple networks per emulation, and let different
                    NICs in machines connect to different networks.
                o)  Network across multiple hosts.
                o)  Fixed MAC addresses for NICs, fixed IPv4 addresses if
                    DHCP or RARP is used.
                o)  many other issues: see src/net.c

        Configure script:
                o)  Only enable Alpha prefetch on pca56 etc, not on ev4, ev5.
                o)  Use getopts?
                o)  X11 libs and headers via command line option?
                o)  Verify that the configure script, building and running
                    the emulator works on some platforms:
                        +)  Irix, AIX, QNX
                        +)  MacOS X  (I've not tried this personally yet)
                        +)  Ultrix using gcc? (Inside the emulator)

        CPU emulation:
                o)  Binary translation:
                        +)  use an Intermediate Representation!
                        +)  recursive translation?
                        +)  basic blocks instead of one-instruction? :)
                        +)  on Alpha: don't assume pca56-like byte load/store?
                        +)  write backends for UltraSparc and MIPS
                        +)  see src/bintrans.c for more info

        MIPS CPU emulation:
                o)  Instructions:
                        o)  Regression tests (see tests/README for more info):
                                o)  Floating point exception handling, and
                                        add more instructions.
                                o)  Finish the MIPS16 translator, and test it!
                                o)  MIPS ISA I, II, III, IV
                                o)  MIPS V (SIMD vector stuff?)
                                o)  MDMX  (MIPS Digital Media Extension)
                                o)  MIPS 3D
                                o)  MIPS MT (Multi-thread stuff) (What's this?)
                        o)  Warn about mis-used bit fields (ie bits that
                            should be all zeroes, warn about if they are not)!
                            Both for coprocessor registers and for instruction
                            opcodes.
                        o)  the special2 stuff is a mess right now
                        o)  warn and/or cause exceptions for unimplemented
                            instructions (depending on CPU type)
                o)  R2000/R3000:
                        x)  R3000 "tri-byte stores". (What's this?)
                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)
                o)  Implement load delays?  Warnings on interlocks.
                o)  Implement all coprocessor 0 bits / functions.
                        x)  coproc 0 selectors! (R4000 ?)
                o)  R4300 (nintendo64, no mmu?), R5900 (playstation2, weird
                        TLB/cache? 128-bit GPRs, new instructions),
                        4K (note: NOT R4000), 5K (note: NOT R5000),
                        R6000 (ISA II), R8000
                o)  Multi-cpu stuff:
                        +)  SGI's NUMA architecture. Study
                                x)  Linux sources
                                x)  SGI's specs on NUMA address space
                        +)  Ultrix?  NetBSD doesn't do SMP on MIPS yet :-(
                        +)  Own experiments with ycx2.

        Emulation of specific machines and devices:
                o)  Clean up stuff to make it possible to emulate multiple
                    (different) machines simultaneously.
                o)  Use same clock for all emulations and machines.
                o)  Clean up the device stuff (registering of devices etc)
                o)  Various SCSI and IDE controllers
                o)  PS/2-style keyboard controller (for several machines)
                o)  Generic busses;
                        x)  PCI:  i/o and interrupts
                        x)  QBus-22 (DECsystem 5500, 5400?)
                o)  DECstations (pmax):
                        x)  ioasic
                        x)  framebuffers:
                                +)  better cursor support, overlays?,
                                +)  2D/3D acceleration, PX[G]
                        x)  status words / control words, make this more
                                portable/cleaner
                        x)  scsi controller(s): sii, DMA for asc
                        x)  serial controllers: ssc, scc (and more work on dc?)
                        x)  nvram on decstation 5000/125:  when using X11,
                                set console=g or similar
                        x)  DECstation 5840? "xbi-based SMP"
                o)  SGI and ARC machines (sgimips, arc):
                        x)  IP32 ("O2"): (Lots of stuff)
                                +)  mec (ethernet)
                                +)  pci
                                +)  ahc (scsi)
                                +)  ps2 kbd
                                +)  memory controller
                                +)  framebuffer/graphics
                                +)  caches
                        x)  more ARCBIOS stuff
                        x)  Memory/interrupt controllers
                        x)  IP30 (Linux with graphics support?)
                        x)  SMP / NUMA?  (SGI and various ARC machines)
                o)  Cobalt:  PCI and interrupt system, ethernet,
                        harddisk controller(s)
                o)  Playstation 2:
                        Hardware:  OHCI usb controller, keyboard, IDE, ...
                        Has an R3000A as a subsystem (!)
                o)  hpcmips:  framebuffer(s) and harddisk controller,
                        among other things
                o)  newsmips:
                        o)  NetBSD/newsmips, get it to detect a "real"
                            model, right now everything is 100% bogus
                o)  Less interesting platforms:
                        o)  mipsco? (NetBSD)
                        o)  wgrisc? (big endian R3000, in OpenBSD's attic)
                        o)  other embedded / evaluation MIPS boards
                        o)  Playstation 1? R3000A. Weird hardware?
                                No FPU, but something as coproc 2.
                        o)  Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp
                                (R4300, 4MB RAM, really weird memory map)

        File/disk handling:
                o)  Read function argument count and types from binaries? (ELF?)
                o)  ELF: separate LE/BE (MIPS instruction format) from LSB/MSB
                        (ELF structure format)?
                o)  Better handling of tape files

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

        Terminal based interactive debugger:
                o)  see src/debugger.c

        GDB interface? (Maybe not necessary; the built-in debugger feels
        more useful.)

        GUI, interactive debugger?  GTK+?  (The GUI _must be optional_!)
                o)  Breakpoints (complex expressions? combinations of register
                        states, memory accesses and so on)
                o)  Instruction trace
                o)  Disassembly of RAM (_NOT_ the same as instruction trace)
                o)  Function call trace
                o)  Inspection of CPU registers/state, coprocessor
                        registers/state, any device registers/state/contents
                        o)  Framebuffers in windows / tabs.
                        o)  Contents of RAM
                o)  "Start new emulation" should allow amount of
                        RAM and nr of cpus to easily be specified.
                        Multiple simultaneous machines should be possible.
                o)  Disk images.

        Regression tests:
                o)  see tests/

        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 X-windows functionality:
                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)  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	$Id: TODO,v 1.125 2005/03/06 08:21:10 debug Exp $
2
3	Here's a short list of what I have left to do on GXemul. This file is a mess.
4	Order is random. Don't trust it to be up-to-date.
5
6
7	Caches / memory hierarchies: (this is mostly MIPS-specific)
8	o) MIPS coproc.c: bits in config registers should reflect
9	correct cache sizes for _all_ CPU types. (currently only
10	implemented for R4000, R1x000, and a few others)
11	o) src/memory*.c: Implement correct cache emulation for
12	all CPU types. (currently only R2000/R3000 is implemented)
13	(per CPU, multiple levels should be possible,
14	associativity etc!)
15	o) R2000/R3000 isn't _100%_ correct, just almost correct :)
16	o) Move the -S (fill mem with random) functionality into the
17	memory.c subsystem, not machine.c or wherever it is now
18	o) ECC stuff, simulation of memory errors? (Machine dependant)
19	o) More than 4GB of emulated RAM, when run on a 32-bit host?
20	(using manual swap-out of blocks to disk, ugly)
21	o) A global command line option should be used to turn
22	cache emulation on or off. When off, caches should be
23	faked like they are right now. When on, caches and
24	memory latencies should be emulated as correctly as
25	possible.
26
27	Network layer:
28	o) Multiple networks per emulation, and let different
29	NICs in machines connect to different networks.
30	o) Network across multiple hosts.
31	o) Fixed MAC addresses for NICs, fixed IPv4 addresses if
32	DHCP or RARP is used.
33	o) many other issues: see src/net.c
34
35	Configure script:
36	o) Only enable Alpha prefetch on pca56 etc, not on ev4, ev5.
37	o) Use getopts?
38	o) X11 libs and headers via command line option?
39	o) Verify that the configure script, building and running
40	the emulator works on some platforms:
41	+) Irix, AIX, QNX
42	+) MacOS X (I've not tried this personally yet)
43	+) Ultrix using gcc? (Inside the emulator)
44
45	CPU emulation:
46	o) Binary translation:
47	+) use an Intermediate Representation!
48	+) recursive translation?
49	+) basic blocks instead of one-instruction? :)
50	+) on Alpha: don't assume pca56-like byte load/store?
51	+) write backends for UltraSparc and MIPS
52	+) see src/bintrans.c for more info
53
54	MIPS CPU emulation:
55	o) Instructions:
56	o) Regression tests (see tests/README for more info):
57	o) Floating point exception handling, and
58	add more instructions.
59	o) Finish the MIPS16 translator, and test it!
60	o) MIPS ISA I, II, III, IV
61	o) MIPS V (SIMD vector stuff?)
62	o) MDMX (MIPS Digital Media Extension)
63	o) MIPS 3D
64	o) MIPS MT (Multi-thread stuff) (What's this?)
65	o) Warn about mis-used bit fields (ie bits that
66	should be all zeroes, warn about if they are not)!
67	Both for coprocessor registers and for instruction
68	opcodes.
69	o) the special2 stuff is a mess right now
70	o) warn and/or cause exceptions for unimplemented
71	instructions (depending on CPU type)
72	o) R2000/R3000:
73	x) R3000 "tri-byte stores". (What's this?)
74	o) R4000 and others:
75	x) watchhi/watchlo exceptions, and other exception
76	handling details
77	o) R10000 and others: (R12000, R14000 ?)
78	x) memory space, exceptions, ...
79	x) use cop0 framemask for tlb lookups
80	(http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi/hdwr/bks/SGI_Developer/books/R10K_UM/sgi_html/t5.Ver.2.0.book_284.html)
81	o) Implement load delays? Warnings on interlocks.
82	o) Implement all coprocessor 0 bits / functions.
83	x) coproc 0 selectors! (R4000 ?)
84	o) R4300 (nintendo64, no mmu?), R5900 (playstation2, weird
85	TLB/cache? 128-bit GPRs, new instructions),
86	4K (note: NOT R4000), 5K (note: NOT R5000),
87	R6000 (ISA II), R8000
88	o) Multi-cpu stuff:
89	+) SGI's NUMA architecture. Study
90	x) Linux sources
91	x) SGI's specs on NUMA address space
92	+) Ultrix? NetBSD doesn't do SMP on MIPS yet :-(
93	+) Own experiments with ycx2.
94
95	Emulation of specific machines and devices:
96	o) Clean up stuff to make it possible to emulate multiple
97	(different) machines simultaneously.
98	o) Use same clock for all emulations and machines.
99	o) Clean up the device stuff (registering of devices etc)
100	o) Various SCSI and IDE controllers
101	o) PS/2-style keyboard controller (for several machines)
102	o) Generic busses;
103	x) PCI: i/o and interrupts
104	x) QBus-22 (DECsystem 5500, 5400?)
105	o) DECstations (pmax):
106	x) ioasic
107	x) framebuffers:
108	+) better cursor support, overlays?,
109	+) 2D/3D acceleration, PX[G]
110	x) status words / control words, make this more
111	portable/cleaner
112	x) scsi controller(s): sii, DMA for asc
113	x) serial controllers: ssc, scc (and more work on dc?)
114	x) nvram on decstation 5000/125: when using X11,
115	set console=g or similar
116	x) DECstation 5840? "xbi-based SMP"
117	o) SGI and ARC machines (sgimips, arc):
118	x) IP32 ("O2"): (Lots of stuff)
119	+) mec (ethernet)
120	+) pci
121	+) ahc (scsi)
122	+) ps2 kbd
123	+) memory controller
124	+) framebuffer/graphics
125	+) caches
126	x) more ARCBIOS stuff
127	x) Memory/interrupt controllers
128	x) IP30 (Linux with graphics support?)
129	x) SMP / NUMA? (SGI and various ARC machines)
130	o) Cobalt: PCI and interrupt system, ethernet,
131	harddisk controller(s)
132	o) Playstation 2:
133	Hardware: OHCI usb controller, keyboard, IDE, ...
134	Has an R3000A as a subsystem (!)
135	o) hpcmips: framebuffer(s) and harddisk controller,
136	among other things
137	o) newsmips:
138	o) NetBSD/newsmips, get it to detect a "real"
139	model, right now everything is 100% bogus
140	o) Less interesting platforms:
141	o) mipsco? (NetBSD)
142	o) wgrisc? (big endian R3000, in OpenBSD's attic)
143	o) other embedded / evaluation MIPS boards
144	o) Playstation 1? R3000A. Weird hardware?
145	No FPU, but something as coproc 2.
146	o) Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp
147	(R4300, 4MB RAM, really weird memory map)
148
149	File/disk handling:
150	o) Read function argument count and types from binaries? (ELF?)
151	o) ELF: separate LE/BE (MIPS instruction format) from LSB/MSB
152	(ELF structure format)?
153	o) Better handling of tape files
154
155	Userland ABI emulation:
156	o) see src/useremul.c
157
158	Terminal based interactive debugger:
159	o) see src/debugger.c
160
161	GDB interface? (Maybe not necessary; the built-in debugger feels
162	more useful.)
163
164	GUI, interactive debugger? GTK+? (The GUI _must be optional_!)
165	o) Breakpoints (complex expressions? combinations of register
166	states, memory accesses and so on)
167	o) Instruction trace
168	o) Disassembly of RAM (_NOT_ the same as instruction trace)
169	o) Function call trace
170	o) Inspection of CPU registers/state, coprocessor
171	registers/state, any device registers/state/contents
172	o) Framebuffers in windows / tabs.
173	o) Contents of RAM
174	o) "Start new emulation" should allow amount of
175	RAM and nr of cpus to easily be specified.
176	Multiple simultaneous machines should be possible.
177	o) Disk images.
178
179	Regression tests:
180	o) see tests/
181
182	Save state of the whole emulated machine, to be able to load it back
183	in later? (Memory, all device's states, all registers and
184	so on. Like taking a snapshot. (SimOS seems to do this,
185	according to its website.))
186
187	Better X-windows functionality:
188	o) CLEAN UP the ugly event code
189	o) Mouse clicks can be "missed" in the current system; this is
190	not good. They should be put on a stack of some kind.
191	o) More 2D and 3D framebuffer acceleration.
192	o) Non-resizable windows? Or choose scaledown depending
193	on size (and center the image, with a black border).
194	o) Different scaledown on different windows?
195	o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
196	o) Keyboard and mouse events:
197	x) Do this for more machines than just DECstation
198	x) more X11 cursor keycodes
199	x) Keys like CTRL, ALT, SHIFT do not get through
200	by themselves (these are necessary for example
201	to change the font of an xterm in X in the
202	emulator)
203	o) Generalize the framebuffer stuff by moving _ALL_ X11
204	specific code to src/x11.c!
205
206	Statistics: (this could be interesting)
207	o) Save to file and show graphics. It should be possible to
208	run gxemul after a simulation to just show the graphics,
209	or convert to a .ppm or .tga or similar.
210	o) memory accesses (to measure cache efficiency and
211	page coloring efficiency)
212	o) nr of simultaneous ASIDs in use in the TLB, for MIPS
213	o) percentage of time spent in different "states", such as
214	running userland code, kernel code, or idling (for CPUs
215	that have such an instruction, or whenever the PC is
216	inside a specific idle-function (address range)).
217	Possible additional state (for example on R3000): caches
218	disabled.
219	o) position of read/write on (SCSI) disks
220