upstream/0.3.4/TODO

$Id: TODO,v 1.139 2005/06/23 06:55:43 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)  many other issues: see src/net.c

        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
                o)  Dynamic-but-not-binary translation?
                o)  All the non-MIPS modes need a bit of work.

        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)  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)  Playstation 2:
                        Hardware:  OHCI usb controller, keyboard, ...
                o)  Less interesting platforms:
                        o)  newsmips:
                                o)  NetBSD/newsmips, get it to detect a "real"
                                    model, right now everything is 100% bogus
                        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)  Better handling of tape files

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

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

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

        Regression tests:  (Should be totally rewritten.)
                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	dpavlin	10	$Id: TODO,v 1.139 2005/06/23 06:55:43 debug Exp $
2	dpavlin	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			Caches / memory hierarchies: (this is mostly MIPS-specific)
7			o) MIPS coproc.c: bits in config registers should reflect
8			correct cache sizes for _all_ CPU types. (currently only
9			implemented for R4000, R1x000, and a few others)
10			o) src/memory*.c: Implement correct cache emulation for
11			all CPU types. (currently only R2000/R3000 is implemented)
12			(per CPU, multiple levels should be possible,
13			associativity etc!)
14			o) R2000/R3000 isn't _100%_ correct, just almost correct :)
15			o) Move the -S (fill mem with random) functionality into the
16			memory.c subsystem, not machine.c or wherever it is now
17			o) ECC stuff, simulation of memory errors? (Machine dependant)
18			o) More than 4GB of emulated RAM, when run on a 32-bit host?
19			(using manual swap-out of blocks to disk, ugly)
20			o) A global command line option should be used to turn
21			cache emulation on or off. When off, caches should be
22			faked like they are right now. When on, caches and
23			memory latencies should be emulated as correctly as
24			possible.
25
26			Network layer:
27			o) Multiple networks per emulation, and let different
28			NICs in machines connect to different networks.
29			o) many other issues: see src/net.c
30
31			CPU emulation:
32			o) Binary translation:
33			+) use an Intermediate Representation!
34			+) recursive translation?
35			+) basic blocks instead of one-instruction? :)
36			+) on Alpha: don't assume pca56-like byte load/store?
37			+) write backends for UltraSparc and MIPS
38			+) see src/bintrans.c for more info
39	dpavlin	10	o) Dynamic-but-not-binary translation?
40	dpavlin	4	o) All the non-MIPS modes need a bit of work.
41	dpavlin	2
42			MIPS CPU emulation:
43			o) Instructions:
44			o) Regression tests (see tests/README for more info):
45			o) Floating point exception handling, and
46			add more instructions.
47			o) Finish the MIPS16 translator, and test it!
48			o) MIPS ISA I, II, III, IV
49			o) MIPS V (SIMD vector stuff?)
50			o) MDMX (MIPS Digital Media Extension)
51			o) MIPS 3D
52			o) MIPS MT (Multi-thread stuff) (What's this?)
53			o) Warn about mis-used bit fields (ie bits that
54			should be all zeroes, warn about if they are not)!
55			Both for coprocessor registers and for instruction
56			opcodes.
57			o) the special2 stuff is a mess right now
58			o) warn and/or cause exceptions for unimplemented
59			instructions (depending on CPU type)
60			o) R2000/R3000:
61			x) R3000 "tri-byte stores". (What's this?)
62			o) R4000 and others:
63			x) watchhi/watchlo exceptions, and other exception
64			handling details
65			o) R10000 and others: (R12000, R14000 ?)
66			x) memory space, exceptions, ...
67			x) use cop0 framemask for tlb lookups
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)
69			o) Implement load delays? Warnings on interlocks.
70			o) Implement all coprocessor 0 bits / functions.
71			x) coproc 0 selectors! (R4000 ?)
72			o) R4300 (nintendo64, no mmu?), R5900 (playstation2, weird
73			TLB/cache? 128-bit GPRs, new instructions),
74			4K (note: NOT R4000), 5K (note: NOT R5000),
75			R6000 (ISA II), R8000
76			o) Multi-cpu stuff:
77			+) SGI's NUMA architecture. Study
78			x) Linux sources
79			x) SGI's specs on NUMA address space
80			+) Ultrix? NetBSD doesn't do SMP on MIPS yet :-(
81			+) Own experiments with ycx2.
82
83			Emulation of specific machines and devices:
84			o) Use same clock for all emulations and machines.
85			o) Clean up the device stuff (registering of devices etc)
86			o) Various SCSI and IDE controllers
87			o) PS/2-style keyboard controller (for several machines)
88			o) Generic busses;
89			x) PCI: i/o and interrupts
90			x) QBus-22 (DECsystem 5500, 5400?)
91			o) DECstations (pmax):
92			x) ioasic
93			x) framebuffers:
94			+) better cursor support, overlays?,
95			+) 2D/3D acceleration, PX[G]
96			x) status words / control words, make this more
97			portable/cleaner
98			x) scsi controller(s): sii, DMA for asc
99			x) serial controllers: ssc, scc (and more work on dc?)
100			x) nvram on decstation 5000/125: when using X11,
101			set console=g or similar
102			x) DECstation 5840? "xbi-based SMP"
103			o) SGI and ARC machines (sgimips, arc):
104			x) IP32 ("O2"): (Lots of stuff)
105			+) mec (ethernet)
106			+) pci
107			+) ahc (scsi)
108			+) ps2 kbd
109			+) memory controller
110			+) framebuffer/graphics
111			+) caches
112			x) more ARCBIOS stuff
113			x) Memory/interrupt controllers
114			x) IP30 (Linux with graphics support?)
115			x) SMP / NUMA? (SGI and various ARC machines)
116	dpavlin	4	o) Playstation 2:
117			Hardware: OHCI usb controller, keyboard, ...
118	dpavlin	2	o) Less interesting platforms:
119	dpavlin	4	o) newsmips:
120			o) NetBSD/newsmips, get it to detect a "real"
121			model, right now everything is 100% bogus
122	dpavlin	2	o) mipsco? (NetBSD)
123			o) wgrisc? (big endian R3000, in OpenBSD's attic)
124			o) other embedded / evaluation MIPS boards
125			o) Playstation 1? R3000A. Weird hardware?
126			No FPU, but something as coproc 2.
127			o) Nintendo 64, http://www.nintendo.com/systems/n64/n64_specs.jsp
128			(R4300, 4MB RAM, really weird memory map)
129
130			File/disk handling:
131			o) Read function argument count and types from binaries? (ELF?)
132			o) Better handling of tape files
133
134			Userland ABI emulation:
135			o) see src/useremul.c
136
137			Terminal based interactive debugger:
138			o) see src/debugger.c
139
140	dpavlin	6	Terminal/console stuff:
141			o) allow emulated serial ports to be connected to the outside
142			world in a more generic way, or even to other emulated
143			machines(!)
144
145	dpavlin	10	Regression tests: (Should be totally rewritten.)
146	dpavlin	2	o) see tests/
147
148			Save state of the whole emulated machine, to be able to load it back
149			in later? (Memory, all device's states, all registers and
150			so on. Like taking a snapshot. (SimOS seems to do this,
151			according to its website.))
152
153			Better X-windows functionality:
154			o) CLEAN UP the ugly event code
155			o) Mouse clicks can be "missed" in the current system; this is
156			not good. They should be put on a stack of some kind.
157			o) More 2D and 3D framebuffer acceleration.
158			o) Non-resizable windows? Or choose scaledown depending
159			on size (and center the image, with a black border).
160			o) Different scaledown on different windows?
161			o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
162			o) Keyboard and mouse events:
163			x) Do this for more machines than just DECstation
164			x) more X11 cursor keycodes
165			x) Keys like CTRL, ALT, SHIFT do not get through
166			by themselves (these are necessary for example
167			to change the font of an xterm in X in the
168			emulator)
169			o) Generalize the framebuffer stuff by moving _ALL_ X11
170			specific code to src/x11.c!
171
172			Statistics: (this could be interesting)
173			o) Save to file and show graphics. It should be possible to
174			run gxemul after a simulation to just show the graphics,
175			or convert to a .ppm or .tga or similar.
176			o) memory accesses (to measure cache efficiency and
177			page coloring efficiency)
178			o) nr of simultaneous ASIDs in use in the TLB, for MIPS
179			o) percentage of time spent in different "states", such as
180			running userland code, kernel code, or idling (for CPUs
181			that have such an instruction, or whenever the PC is
182			inside a specific idle-function (address range)).
183			Possible additional state (for example on R3000): caches
184			disabled.
185			o) position of read/write on (SCSI) disks
186