upstream/0.3.6.2/TODO

$Id: TODO,v 1.175 2005/10/23 14:24:09 debug Exp $

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

High priority stuff:


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.

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

Lower priority, but still important:

        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 1.175 2005/10/23 14:24:09 debug Exp $
2
3	===============================================================================
4
5	High priority stuff:
6
7
8	Old MIPS bintrans:
9
10	x) call/return address cache?
11
12	x) Turn the MIPS cpu family stuff into dyntrans.
13
14
15	Dyntrans:
16
17	x) Separate data and instruction translations?
18
19	x) Generalize the inline quick_pc_to_pointers?
20
21	x) Call/return hints...
22
23	x) More 64-bit stuff.
24
25	x) Lots of other stuff: see src/cpus/README_DYNTRANS
26
27
28	Userland emulation:
29
30	x) Lots of stuff.
31
32	x) Dynamic linking? Hm.
33
34	===============================================================================
35
36	Lower priority, but still important:
37
38	Redesign the entire "mainbus" concept:
39	o) Easily configurable interrupt routing in SMP systems.
40	o) Specific clock/bus speeds, cpu speeds etc.
41	o) Synchronization over network?
42
43	Caches / memory hierarchies: (this is mostly MIPS-specific)
44	o) MIPS coproc.c: bits in config registers should reflect
45	correct cache sizes for _all_ CPU types. (currently only
46	implemented for R4000, R1x000, and a few others)
47	o) src/memory*.c: Implement correct cache emulation for
48	all CPU types. (currently only R2000/R3000 is implemented)
49	(per CPU, multiple levels should be possible,
50	associativity etc!)
51	o) R2000/R3000 isn't _100%_ correct, just almost correct :)
52	o) Move the -S (fill mem with random) functionality into the
53	memory.c subsystem, not machine.c or wherever it is now
54	o) ECC stuff, simulation of memory errors? (Machine dependant)
55	o) More than 4GB of emulated RAM, when run on a 32-bit host?
56	(using manual swap-out of blocks to disk, ugly)
57	o) A global command line option should be used to turn
58	cache emulation on or off. When off, caches should be
59	faked like they are right now. When on, caches and
60	memory latencies should be emulated as correctly as
61	possible.
62
63	Network layer:
64	o) Multiple networks per emulation, and let different
65	NICs in machines connect to different networks.
66	o) many other issues: see src/net.c
67
68	MIPS CPU emulation:
69	o) i386 bintrans backend: movn etc, slt[u] for
70	64-bit mode, 64-bit shifts etc
71	o) Instructions:
72	o) All ISAs:
73	o) Floating point exception handling, and
74	add more instructions.
75	o) Finish the MIPS16 translator, and test it!
76	o) MIPS ISA I, II, III, IV
77	o) MIPS V (SIMD vector stuff?)
78	o) MDMX (MIPS Digital Media Extension)
79	o) MIPS 3D
80	o) MIPS MT (Multi-thread stuff) (What's this?)
81	o) Warn about mis-used bit fields (ie bits that
82	should be all zeroes, warn about if they are not)!
83	Both for coprocessor registers and for instruction
84	opcodes.
85	o) the special2 stuff is a mess right now
86	o) warn and/or cause exceptions for unimplemented
87	instructions (depending on CPU type)
88	o) R2000/R3000:
89	x) R3000 "tri-byte stores". (What's this?)
90	o) R4000 and others:
91	x) watchhi/watchlo exceptions, and other exception
92	handling details
93	o) R10000 and others: (R12000, R14000 ?)
94	x) memory space, exceptions, ...
95	x) use cop0 framemask for tlb lookups
96	(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)
97	o) Implement load delays? Warnings on interlocks.
98	o) Implement all coprocessor 0 bits / functions.
99	x) coproc 0 selectors! (R4000 ?)
100	o) R4300 (nintendo64, no mmu?), R5900 (playstation2, weird
101	TLB/cache? 128-bit GPRs, new instructions),
102	4K (note: NOT R4000), 5K (note: NOT R5000),
103	R6000 (ISA II), R8000
104	o) Multi-cpu stuff:
105	+) Interrupt routing (ie devices vs mainbus, or
106	connect each device to a fixed cpu)
107	+) SGI's NUMA architecture. Study
108	x) Linux sources
109	x) SGI's specs on NUMA address space
110	+) Ultrix? NetBSD doesn't do SMP on MIPS yet :-(
111	+) Own experiments with ycx2.
112
113	File/disk handling:
114	o) Better handling of tape files
115
116	Debugger:
117	o) Read function argument count and types from binaries? (ELF?)
118	o) Demangle C++ names.
119	o) see src/debugger.c for more stuff
120
121	Userland ABI emulation:
122	o) see src/useremul.c
123
124	Terminal/console stuff:
125	o) allow emulated serial ports to be connected to the outside
126	world in a more generic way, or even to other emulated
127	machines(!)
128
129	Regression tests. (Needs to be totally rewritten, the old framework
130	was removed because it was useless.)
131
132	Save state of the whole emulated machine, to be able to load it back
133	in later? (Memory, all device's states, all registers and
134	so on. Like taking a snapshot. (SimOS seems to do this,
135	according to its website.))
136
137	Better X-windows functionality:
138	o) CLEAN UP the ugly event code
139	o) Mouse clicks can be "missed" in the current system; this is
140	not good. They should be put on a stack of some kind.
141	o) More 2D and 3D framebuffer acceleration.
142	o) Non-resizable windows? Or choose scaledown depending
143	on size (and center the image, with a black border).
144	o) Different scaledown on different windows?
145	o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
146	o) Keyboard and mouse events:
147	x) Do this for more machines than just DECstation
148	x) more X11 cursor keycodes
149	x) Keys like CTRL, ALT, SHIFT do not get through
150	by themselves (these are necessary for example
151	to change the font of an xterm in X in the
152	emulator)
153	o) Generalize the framebuffer stuff by moving _ALL_ X11
154	specific code to src/x11.c!
155
156	Statistics: (this could be interesting)
157	o) Save to file and show graphics. It should be possible to
158	run gxemul after a simulation to just show the graphics,
159	or convert to a .ppm or .tga or similar.
160	o) memory accesses (to measure cache efficiency and
161	page coloring efficiency)
162	o) nr of simultaneous ASIDs in use in the TLB, for MIPS
163	o) percentage of time spent in different "states", such as
164	running userland code, kernel code, or idling (for CPUs
165	that have such an instruction, or whenever the PC is
166	inside a specific idle-function (address range)).
167	Possible additional state (for example on R3000): caches
168	disabled.
169	o) position of read/write on (SCSI) disks
170