upstream/0.3.6/TODO

$Id: TODO,v 1.173 2005/09/17 17:14:25 debug Exp $

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

High priority stuff:


Old MIPS bintrans:

        x)  call/return address cache?

        x)  Turn the MIPS cpu family stuff into dyntrans.


Dyntrans:

        x)  Lots of 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	dpavlin	14	$Id: TODO,v 1.173 2005/09/17 17:14:25 debug Exp $
2	dpavlin	2
3	dpavlin	12	===============================================================================
4	dpavlin	2
5	dpavlin	12	High priority stuff:
6
7
8	dpavlin	14	Old MIPS bintrans:
9
10	dpavlin	12	x) call/return address cache?
11
12	dpavlin	14	x) Turn the MIPS cpu family stuff into dyntrans.
13	dpavlin	12
14
15	dpavlin	14	Dyntrans:
16	dpavlin	12
17	dpavlin	14	x) Lots of stuff: see src/cpus/README_DYNTRANS
18	dpavlin	12
19
20	dpavlin	14	Userland emulation:
21	dpavlin	12
22	dpavlin	14	x) Lots of stuff.
23	dpavlin	12
24	dpavlin	14	x) Dynamic linking? Hm.
25	dpavlin	12
26			===============================================================================
27
28			Lower priority, but still important:
29
30			Redesign the entire "mainbus" concept:
31			o) Easily configurable interrupt routing in SMP systems.
32			o) Specific clock/bus speeds, cpu speeds etc.
33			o) Synchronization over network?
34
35	dpavlin	2	Caches / memory hierarchies: (this is mostly MIPS-specific)
36			o) MIPS coproc.c: bits in config registers should reflect
37			correct cache sizes for _all_ CPU types. (currently only
38			implemented for R4000, R1x000, and a few others)
39			o) src/memory*.c: Implement correct cache emulation for
40			all CPU types. (currently only R2000/R3000 is implemented)
41			(per CPU, multiple levels should be possible,
42			associativity etc!)
43			o) R2000/R3000 isn't _100%_ correct, just almost correct :)
44			o) Move the -S (fill mem with random) functionality into the
45			memory.c subsystem, not machine.c or wherever it is now
46			o) ECC stuff, simulation of memory errors? (Machine dependant)
47			o) More than 4GB of emulated RAM, when run on a 32-bit host?
48			(using manual swap-out of blocks to disk, ugly)
49			o) A global command line option should be used to turn
50			cache emulation on or off. When off, caches should be
51			faked like they are right now. When on, caches and
52			memory latencies should be emulated as correctly as
53			possible.
54
55			Network layer:
56			o) Multiple networks per emulation, and let different
57			NICs in machines connect to different networks.
58			o) many other issues: see src/net.c
59
60			MIPS CPU emulation:
61	dpavlin	12	o) i386 bintrans backend: movn etc, slt[u] for
62			64-bit mode, 64-bit shifts etc
63	dpavlin	2	o) Instructions:
64	dpavlin	12	o) All ISAs:
65	dpavlin	2	o) Floating point exception handling, and
66			add more instructions.
67			o) Finish the MIPS16 translator, and test it!
68			o) MIPS ISA I, II, III, IV
69			o) MIPS V (SIMD vector stuff?)
70			o) MDMX (MIPS Digital Media Extension)
71			o) MIPS 3D
72			o) MIPS MT (Multi-thread stuff) (What's this?)
73			o) Warn about mis-used bit fields (ie bits that
74			should be all zeroes, warn about if they are not)!
75			Both for coprocessor registers and for instruction
76			opcodes.
77			o) the special2 stuff is a mess right now
78			o) warn and/or cause exceptions for unimplemented
79			instructions (depending on CPU type)
80			o) R2000/R3000:
81			x) R3000 "tri-byte stores". (What's this?)
82			o) R4000 and others:
83			x) watchhi/watchlo exceptions, and other exception
84			handling details
85			o) R10000 and others: (R12000, R14000 ?)
86			x) memory space, exceptions, ...
87			x) use cop0 framemask for tlb lookups
88			(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)
89			o) Implement load delays? Warnings on interlocks.
90			o) Implement all coprocessor 0 bits / functions.
91			x) coproc 0 selectors! (R4000 ?)
92			o) R4300 (nintendo64, no mmu?), R5900 (playstation2, weird
93			TLB/cache? 128-bit GPRs, new instructions),
94			4K (note: NOT R4000), 5K (note: NOT R5000),
95			R6000 (ISA II), R8000
96			o) Multi-cpu stuff:
97	dpavlin	12	+) Interrupt routing (ie devices vs mainbus, or
98			connect each device to a fixed cpu)
99	dpavlin	2	+) SGI's NUMA architecture. Study
100			x) Linux sources
101			x) SGI's specs on NUMA address space
102			+) Ultrix? NetBSD doesn't do SMP on MIPS yet :-(
103			+) Own experiments with ycx2.
104
105			File/disk handling:
106			o) Better handling of tape files
107
108	dpavlin	12	Debugger:
109			o) Read function argument count and types from binaries? (ELF?)
110			o) Demangle C++ names.
111	dpavlin	14	o) see src/debugger.c for more stuff
112	dpavlin	12
113	dpavlin	2	Userland ABI emulation:
114			o) see src/useremul.c
115
116	dpavlin	6	Terminal/console stuff:
117			o) allow emulated serial ports to be connected to the outside
118			world in a more generic way, or even to other emulated
119			machines(!)
120
121	dpavlin	12	Regression tests. (Needs to be totally rewritten, the old framework
122			was removed because it was useless.)
123	dpavlin	2
124			Save state of the whole emulated machine, to be able to load it back
125			in later? (Memory, all device's states, all registers and
126			so on. Like taking a snapshot. (SimOS seems to do this,
127			according to its website.))
128
129			Better X-windows functionality:
130			o) CLEAN UP the ugly event code
131			o) Mouse clicks can be "missed" in the current system; this is
132			not good. They should be put on a stack of some kind.
133			o) More 2D and 3D framebuffer acceleration.
134			o) Non-resizable windows? Or choose scaledown depending
135			on size (and center the image, with a black border).
136			o) Different scaledown on different windows?
137			o) Switch scaledown during runtime? (Ala CTRL-ALT-plus/minus)
138			o) Keyboard and mouse events:
139			x) Do this for more machines than just DECstation
140			x) more X11 cursor keycodes
141			x) Keys like CTRL, ALT, SHIFT do not get through
142			by themselves (these are necessary for example
143			to change the font of an xterm in X in the
144			emulator)
145			o) Generalize the framebuffer stuff by moving _ALL_ X11
146			specific code to src/x11.c!
147
148			Statistics: (this could be interesting)
149			o) Save to file and show graphics. It should be possible to
150			run gxemul after a simulation to just show the graphics,
151			or convert to a .ppm or .tga or similar.
152			o) memory accesses (to measure cache efficiency and
153			page coloring efficiency)
154			o) nr of simultaneous ASIDs in use in the TLB, for MIPS
155			o) percentage of time spent in different "states", such as
156			running userland code, kernel code, or idling (for CPUs
157			that have such an instruction, or whenever the PC is
158			inside a specific idle-function (address range)).
159			Possible additional state (for example on R3000): caches
160			disabled.
161			o) position of read/write on (SCSI) disks
162