upstream/0.3.7/TODO

$Id: TODO,v 1.176 2005/11/13 00:14:05 debug Exp $

NOTE: This TODO is hopefully out-of-date. I don't keep it updated.

===============================================================================

Old MIPS bintrans:
        x)  call/return address cache?
        x)  Turn the MIPS cpu family stuff into dyntrans.

Dyntrans:
        x)  Separate data and instruction translations?
        x)  Generalize the inline quick_pc_to_pointers?
        x)  Call/return hints...
        x)  More 64-bit stuff.
        x)  Lots of other stuff: see src/cpus/README_DYNTRANS

Userland emulation:
        x)  Lots of stuff.
        x)  Dynamic linking? Hm.

Misc:
        Redesign the entire "mainbus" concept:
                o)  Easily configurable interrupt routing in SMP systems.
                o)  Specific clock/bus speeds, cpu speeds etc.
                o)  Synchronization over network?

        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

        MIPS CPU emulation:
                o)  i386 bintrans backend: movn etc, slt[u] for
                        64-bit mode, 64-bit shifts etc
                o)  Instructions:
                        o)  All ISAs:
                                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:
                        +)  Interrupt routing (ie devices vs mainbus, or
                            connect each device to a fixed cpu)
                        +)  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.

        File/disk handling:
                o)  Better handling of tape files

        Debugger:
                o)  Read function argument count and types from binaries? (ELF?)
                o)  Demangle C++ names.
                o)  see src/debugger.c for more stuff

        Userland ABI emulation:
                o)  see src/useremul.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.  (Needs to be totally rewritten, the old framework
                was removed because it was useless.)

        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 1.176 2005/11/13 00:14:05 debug Exp $
2
3	NOTE: This TODO is hopefully out-of-date. I don't keep it updated.
4
5	===============================================================================
6
7	Old MIPS bintrans:
8	x) call/return address cache?
9	x) Turn the MIPS cpu family stuff into dyntrans.
10
11	Dyntrans:
12	x) Separate data and instruction translations?
13	x) Generalize the inline quick_pc_to_pointers?
14	x) Call/return hints...
15	x) More 64-bit stuff.
16	x) Lots of other stuff: see src/cpus/README_DYNTRANS
17
18	Userland emulation:
19	x) Lots of stuff.
20	x) Dynamic linking? Hm.
21
22	Misc:
23	Redesign the entire "mainbus" concept:
24	o) Easily configurable interrupt routing in SMP systems.
25	o) Specific clock/bus speeds, cpu speeds etc.
26	o) Synchronization over network?
27
28	Caches / memory hierarchies: (this is mostly MIPS-specific)
29	o) MIPS coproc.c: bits in config registers should reflect
30	correct cache sizes for _all_ CPU types. (currently only
31	implemented for R4000, R1x000, and a few others)
32	o) src/memory*.c: Implement correct cache emulation for
33	all CPU types. (currently only R2000/R3000 is implemented)
34	(per CPU, multiple levels should be possible,
35	associativity etc!)
36	o) R2000/R3000 isn't _100%_ correct, just almost correct :)
37	o) Move the -S (fill mem with random) functionality into the
38	memory.c subsystem, not machine.c or wherever it is now
39	o) ECC stuff, simulation of memory errors? (Machine dependant)
40	o) More than 4GB of emulated RAM, when run on a 32-bit host?
41	(using manual swap-out of blocks to disk, ugly)
42	o) A global command line option should be used to turn
43	cache emulation on or off. When off, caches should be
44	faked like they are right now. When on, caches and
45	memory latencies should be emulated as correctly as
46	possible.
47
48	Network layer:
49	o) Multiple networks per emulation, and let different
50	NICs in machines connect to different networks.
51	o) many other issues: see src/net.c
52
53	MIPS CPU emulation:
54	o) i386 bintrans backend: movn etc, slt[u] for
55	64-bit mode, 64-bit shifts etc
56	o) Instructions:
57	o) All ISAs:
58	o) Floating point exception handling, and
59	add more instructions.
60	o) Finish the MIPS16 translator, and test it!
61	o) MIPS ISA I, II, III, IV
62	o) MIPS V (SIMD vector stuff?)
63	o) MDMX (MIPS Digital Media Extension)
64	o) MIPS 3D
65	o) MIPS MT (Multi-thread stuff) (What's this?)
66	o) Warn about mis-used bit fields (ie bits that
67	should be all zeroes, warn about if they are not)!
68	Both for coprocessor registers and for instruction
69	opcodes.
70	o) the special2 stuff is a mess right now
71	o) warn and/or cause exceptions for unimplemented
72	instructions (depending on CPU type)
73	o) R2000/R3000:
74	x) R3000 "tri-byte stores". (What's this?)
75	o) R4000 and others:
76	x) watchhi/watchlo exceptions, and other exception
77	handling details
78	o) R10000 and others: (R12000, R14000 ?)
79	x) memory space, exceptions, ...
80	x) use cop0 framemask for tlb lookups
81	(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)
82	o) Implement load delays? Warnings on interlocks.
83	o) Implement all coprocessor 0 bits / functions.
84	x) coproc 0 selectors! (R4000 ?)
85	o) R4300 (nintendo64, no mmu?), R5900 (playstation2, weird
86	TLB/cache? 128-bit GPRs, new instructions),
87	4K (note: NOT R4000), 5K (note: NOT R5000),
88	R6000 (ISA II), R8000
89	o) Multi-cpu stuff:
90	+) Interrupt routing (ie devices vs mainbus, or
91	connect each device to a fixed cpu)
92	+) SGI's NUMA architecture. Study
93	x) Linux sources
94	x) SGI's specs on NUMA address space
95	+) Ultrix? NetBSD doesn't do SMP on MIPS yet :-(
96	+) Own experiments with ycx2.
97
98	File/disk handling:
99	o) Better handling of tape files
100
101	Debugger:
102	o) Read function argument count and types from binaries? (ELF?)
103	o) Demangle C++ names.
104	o) see src/debugger.c for more stuff
105
106	Userland ABI emulation:
107	o) see src/useremul.c
108
109	Terminal/console stuff:
110	o) allow emulated serial ports to be connected to the outside
111	world in a more generic way, or even to other emulated
112	machines(!)
113
114	Regression tests. (Needs to be totally rewritten, the old framework
115	was removed because it was useless.)
116
117	Save state of the whole emulated machine, to be able to load it back
118	in later? (Memory, all device's states, all registers and
119	so on. Like taking a snapshot. (SimOS seems to do this,
120	according to its website.))
121
122	Better X-windows functionality:
123	o) CLEAN UP the ugly event code
124	o) Mouse clicks can be "missed" in the current system; this is
125	not good. They should be put on a stack of some kind.
126	o) More 2D and 3D framebuffer acceleration.
127	o) Non-resizable windows? Or choose scaledown depending
128	on size (and center the image, with a black border).
129	o) Different scaledown on different windows?
130	o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
131	o) Keyboard and mouse events:
132	x) Do this for more machines than just DECstation
133	x) more X11 cursor keycodes
134	x) Keys like CTRL, ALT, SHIFT do not get through
135	by themselves (these are necessary for example
136	to change the font of an xterm in X in the
137	emulator)
138	o) Generalize the framebuffer stuff by moving _ALL_ X11
139	specific code to src/x11.c!
140
141	Statistics: (this could be interesting)
142	o) Save to file and show graphics. It should be possible to
143	run gxemul after a simulation to just show the graphics,
144	or convert to a .ppm or .tga or similar.
145	o) memory accesses (to measure cache efficiency and
146	page coloring efficiency)
147	o) nr of simultaneous ASIDs in use in the TLB, for MIPS
148	o) percentage of time spent in different "states", such as
149	running userland code, kernel code, or idling (for CPUs
150	that have such an instruction, or whenever the PC is
151	inside a specific idle-function (address range)).
152	Possible additional state (for example on R3000): caches
153	disabled.
154	o) position of read/write on (SCSI) disks
155