TODO

mips64emul TODO
---------------

This file is a mess. Order is random. Don't trust it to be up-to-date.


	Caches / memory hierarchies:
		o)  Implement correct cache emulation (per CPU, multiple
		    levels should be possible)
		o)  Move the -H (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)  Cache latencies in number of cycles or instructions.
		    Should device reads/writes also return the number of
		    cycles they used?
		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.

	Binary translation:  src/bintrans.c

	Network layer
		o)  ethernet interfaces
		o)  (userland, non-root) network stack

	Command line option parsing:
		o)  Use only one letter for selecting machine type (followed
		    by a substring of the machine type), not one letter
		    for each machine type as it is now.

	CPU Emulation:
		o)  Factor out the MIPS dependant parts of the cpu, so that
		    (in theory) the emulator could support other architectures
		    as well.   (sparc64?)
		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 V (SIMD vector stuff?)
			o)  MDMX?  (MIPS Digital Media Extension)
			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)  warn and/or cause exceptions for unimplemented
			    instructions (depending on CPU type)
		o)  Nr of instructions per second is NOT the number of cycles
		    per second, this is CPU dependant.  Several subsystems
		    (CPUs, other systems) may need to have speeds fixed
		    relative to each other.
		o)  R2000/R3000:
			x)  Make sure that registers (INCLUDING coprocessor
			    registers) are always sign-extended. (32-bit stuff)
			x)  R3000 "tri-byte stores"???
		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 ?)
			x)  BEV and all exception vectors....
		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

	Emulation of specific machines and devices:
		o)  SCSI controllers!
		o)  "wdc" IDE controller!
		o)  Busses, interrupt systems, and ROM emulation:
			x)  Make interrupt sharing more generic!
			x)  PCI:  i/o and interrupts
			x)  TURBOchannel  (many DEC systems)
			x)  ARCBIOS (SGI, arc?)
			x)  QBus-22 (DECsystem 5500, 5400?)
		o)  DECstations (pmax):
			framebuffers:
				better cursor support, overlays?,
				2D/3D acceleration, PX[G]
			status words / control words, make this more
				portable/cleaner
			scsi controller(s): sii, asc (+ DMA)
			ethernet controller(s): le, fddi?
			serial controllers: dc, ssc, scc
			nvram on decstation 5000/125:  when using X11,
				set console=g or similar
			DECstation 5840? "xbi-based SMP"
		o)  SGI and ARC machines (sgimips, arc):
			x)  Finish the SGI O2 framebuffer and keyboard support
			x)  SMP / NUMA?
			x)  Jazz (ARC)
			x)  Interrupts (PCI and others) (both ARC and SGI)
		o)  Cobalt:  PCI and interrupt system, ethernet,
			harddisk controller(s)
		o)  Playstation 2:
			R5900 "weird" instructions (most needed by Linux
				and NetBSD are already implemented, but
				perhaps others are needed as well)
			Hardware:  OHCI usb controller, keyboard,
				IDE controller, ...
			Has an R3000A as a subsystem (!)
		o)  hpcmips:  framebuffer(s) and harddisk controller,
			among other things
		o)  newsmips?
		o)  mipsco?
		o)  Less interesting platforms:
			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)

	Multi-cpu stuff:
		o)  SGI's NUMA architecture. Study
			x)  Linux sources
			x)  SGI's specs on NUMA address space
		o)  Ultrix?  (NetBSD is not SMP yet on any MIPS platform,
			it seems.)
		o)  Own experiments with ycx2.

	File/disk handling:
		o)  Read function argument count and types from binaries? (ELF?)
		o)  zlib support (should be optional) for:
			x)  loading gzipped kernels directly
			x)  (read-only) disk images (?)
		o)  ELF: separate LE/BE (MIPS instruction format) from LSB/MSB
			(ELF structure format)?
		o)  Better handling of tape files

	Userland ABI emulation: src/useremul.c

	GUI, interactive debugger?  GTK+?  (The GUI _must be optional_!)
		o)  Breakpoints (complex expressions? combinations of register
			states, memory accesses and so on)
		o)  Instruction trace
		o)  Disassembly of RAM (_NOT_ the same as instruction trace)
		o)  Function call trace
		o)  Inspection of CPU registers/state, coprocessor
			registers/state, any device registers/state/contents
			o)  Framebuffers in windows / tabs.
			o)  Contents of RAM
		o)  "Start new emulation" should allow amount of
			RAM and nr of cpus to easily be specified.
			Multiple simultaneous machines should be possible.
		o)  Disk images.

	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)

	Better X-windows functionality:
		o)  Cursor transparency masking
		o)  More 2D and 3D framebuffer acceleration
		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)  How about multiple framebuffer windows?
			x)  Try to make the emulated mouse cursor coordinates
				track the host's X11 mouse! (This might be
				bad to enable if the cursor is for example
				a text console cursor.)
			x)  X11 cursor keycodes and such?
		o)  Non-resizable windows?
		o)  Generalize the framebuffer stuff by moving _ALL_ X11
			specific code to src/x11.c!

	Statistics:  (this could be interesting)
		o)  memory accesses (to measure cache efficiency and
			page coloring efficiency)
		o)  nr-of-instructions-in-a-row-that-don't-affect-eachother,
			and make histograms of this data
		o)  nr of simultaneous ASIDs in use in the TLB  (x = time)
		o)  position of read/write on (SCSI) disks   (x = time)

	Write Documentation:
		o)  A very tiny manpage
		o)  User Documentation (HTML)
		o)  Technical Documentation (HTML)