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NOTE: This TODO is hopefully out-of-date.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	dpavlin	20	$Id: TODO,v 1.176 2005/11/13 00:14:05 debug Exp $
2	dpavlin	2
3	dpavlin	20	NOTE: This TODO is hopefully out-of-date. I don't keep it updated.
4
5	dpavlin	12	===============================================================================
6	dpavlin	2
7	dpavlin	14	Old MIPS bintrans:
8	dpavlin	12	x) call/return address cache?
9	dpavlin	14	x) Turn the MIPS cpu family stuff into dyntrans.
10	dpavlin	12
11	dpavlin	14	Dyntrans:
12	dpavlin	18	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	dpavlin	14	Userland emulation:
19			x) Lots of stuff.
20			x) Dynamic linking? Hm.
21	dpavlin	12
22	dpavlin	20	Misc:
23	dpavlin	12	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	dpavlin	2	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	dpavlin	12	o) i386 bintrans backend: movn etc, slt[u] for
55			64-bit mode, 64-bit shifts etc
56	dpavlin	2	o) Instructions:
57	dpavlin	12	o) All ISAs:
58	dpavlin	2	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	dpavlin	12	+) Interrupt routing (ie devices vs mainbus, or
91			connect each device to a fixed cpu)
92	dpavlin	2	+) 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	dpavlin	12	Debugger:
102			o) Read function argument count and types from binaries? (ELF?)
103			o) Demangle C++ names.
104	dpavlin	14	o) see src/debugger.c for more stuff
105	dpavlin	12
106	dpavlin	2	Userland ABI emulation:
107			o) see src/useremul.c
108
109	dpavlin	6	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	dpavlin	12	Regression tests. (Needs to be totally rewritten, the old framework
115			was removed because it was useless.)
116	dpavlin	2
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