HISTORY

$Id: HISTORY,v 1.123 2004/07/02 09:27:03 debug Exp $

HISTORY of mips64emul
---------------------

20030829	Skeleton. ELF stuff. Some instructions.
20030830	Simple test programs using +-*/^|&%, function calls,
		loops, and stuff like that work.
20030903	Adding more instructions, fixing some bugs.
20030907	Making adding of memory mapped devices easier, although
		the framework isn't built for speed.
		Adding a -q switch to turn of debug output.
20030911	Trying to fix some bugs. Minor changes. Some COP0
		registers are now meaningful.
20030919	Making APs (non-bootstrap cpus) available via a simple
		'mp' device. Implementing ll/lld and sc/scd (for atomic
		memory updates, needed by MP operating systems).
20030923	Minor updates: more instructions (divu, mulu, lwu,
		perhaps some more), and opcode usage statistics.
20030924	If the next instruction is nullified (for 'branch
		likely' type of instructions), counters for delays etc
		are now decreased as they should.
		Adding some comments.
		Adding instructions: movz, movn.
		Adding a simple mandelbrot test to mipstest.c.
20030925	Adding instructions: bltzl, bgezl, lh, lhu, sh, mfc*,
		mtc*.
		Adding a dummy instructions: sync, cache.
		Adding minimal DECstation PROM functionality: printf()
		and getsysid() callback functions.
		Beginning work on address translation.
20030927	Adding some more cop0 functionality (tlb stuff).
		Adding mc146818 real-time clock. (Skeleton stuff.)
20030928	Adding a dc7085 serial console device (dummy, but enough
		to output chars to the screen). NetBSD uses this for
		the MIPSMATE 5100.
20030929	Working on the TLB stuff.
		Adding instructions: srlv, tlbwr, tlbr, tlbp, eret.
20030930	Trying to find a bug which causes NetBSD to bug out, but
		it is really hard.
		Adding some a.out support (for loading an old
		OpenBSD 2.8/pmax kernel image).
		Adding instructions: lwc*, ldc*, swc1 and swc3.
		Beginning to add special code to handle the differences
		between R4000 (the default emulation) and R2000/R3000.
20031001	Symbol listings produced by 'nm -S' can be used to
		show symbolic names for addresses. (-S)
20031002	Fixing the i/d fake cache for R2000/R3000. It's still
		just an ugly hack, though.
		Fixing minor bugs to make the 3100 emulation use the
		dc device (serial console) correctly. So far, 5100 and
		3100 are the only ones that get far enough to print
		stuff, when booting NetBSD.
20031004	Adding skeleton Cobalt machine emulation (-E).
		Adding a dummy ns16550 serial controller, used by the
		Cobalt machine emulation.
20031006	Adding unaligned load/store instructions (lwl, lwr,
		ldl, ldr, swl, swr, sdl, sdr), although they are not
		tested yet.
		Fixed a "data modified on freelist" bug when running
		NetBSD/cobalt: setting the top bit of the index register
		when a tlbp fails (as the R4000 manual says) isn't
		sufficient, I had to clear the low bits as well.
		Adding break and syscall instructions, but they are not
		tested yet.
		Adding a 'gt' device, faking a PCI bus, for the Cobalt
		emulation.
20031008	Adding initial support for HPCmips (-F), a framebuffer
		device using X11. NetBSD/hpcmips can output pixels to
		the framebuffer, but that's about it.
20031009	Fixing the NetBSD/pmax bug: the "0/tftp/netbsd" style
		bootstring was only passed correctly in the bootinfo
		block, it needs to be passed as argv[0] as well.
		Adding instructions: mtlo, mthi.
		Rearrangning the source tree layout.
		Adding console input functionality. The NetBSD/cobalt
		kernel's ddb can now be interacted with.
20031010	Adding experimental (semi-useless) -t option, to show
		a function call tree while a program runs.
		Linux/cobalt now prints a few messages, but then hangs
		at "Calibrating delay loop..." unless an ugly hack is
		used (setting a word of memory at 0x801e472c to non-zero).
20031013	Adding a framebuffer device used in DECstation 3100;
		VFB01 for mono is implemented so far, not yet the
		VFB02 (color) variant.  Rewriting the framebuffer
		device so that it is usable by both HPCmips and DECstation
		emulation.
20031014	Minor fixes. Everything should compile and run ok
		both with and without X11.
20031015	Adding support for ECOFF binary images; text, data,
		and symbols are loaded. (Playing around with ultrixboot
		and ultrix kernels.)
20031016	The DECstation argv,argc stuff must be at 0xa0000000,
		not 0x80000000, or Ultrix kernels complain.
		Adding R2000/R3000 'rfe' instruction.
		Implementing more R2K/R3K tlb specific stuff, so that
		NetBSD boots and uses the tlb correctly, but much of
		it is ugly. (Needs to be separated in a cleaner way.)
		ECOFF symbols sizes are now calculated, so that offsets
		within symbols are usable.
20031017	DECstation bootstrings now automatically include the
		correct name of the kernel that is booting.
		Ultrix boots a bit.
20031018	ELF symbols are now read automatically from the binary.
		-t trace looks a bit better (string arguments are shown).
		Trying to get initial R5900 stuff working (the 128-bit
		CPU used in Playstation 2).
		Fixing a minor bug to make the VFB02 (color framebuffer)
		device work better, but it is still just 256 grayscales,
		not real color. Ultrix can now use the framebuffer (it
		calls it PMAX-CFB).
		A machine can now consist of CPUs of different types.
		Adding instructions: daddi, mov_xxx, mult_xx. The xxx
		instructions are not documented MIPS64 instructions,
		but NetBSD/playstation2 uses them. Perhaps VR5432
		instructions?
		Adding sign-extension to 32-bit mult.
		Adding Playstation 2 devices: dmac (DMA controller),
		gs (Graphic something?), and gif (graphics something
		else, which has access to the PS2's framebuffer).
		NetBSD/playstation2 works a bit, and prints a few
		bootup messages.
20031020	The cpu_type field of the cpu struct now contains
		usable values in a much better form than before. This
		simplifies adding of new CPU types.
20031021	Fixing an interrupt related bug: pc_last was used, but
		for interrupts this was incorrect. Fixed now.
		Fixing a load/store related bug: if a load into a
		register was aborted due to an exception, the register
		was still modified.
		The mc146818 rtc now reads its time from the system's
		time() function.
		Fixing another exception bug: if loading an instruction
		caused an exception, something bogus happened as the
		emulator tried to execute the instruction anyway. This
		has been fixed now.
20031023	Adding a quick hack which skips "while (reg --) ;"
		kind of loops.
		NetBSD/pmax suddenly reached userland (!), but only
		once and attempts to repeat it have failed. I believe
		it is problems with my interrupt handling system.
20031024	Adding 8-bit color palette support to the framebuffer.
		Connecting the pmax vdac device to the framebuffer's
		rgb palette.
		Fixing a bug in the dc device, so that console input
		is possible; interaction with NetBSD/pmax's built-in
		kernel debugger works now.
		Symbol sizes for file formats where symbol size isn't
		included are now calculated regardless of file format.
		Physical memory space can now be smaller than 64 bits,
		improving emulation speed a bit.
		Doing other minor performance enhancements by moving
		around some statements in critical parts of the code.
20031025	Minor changes to the dc device.
20031026	Adding support for reading symbols directly from
		a.out files. (Works with OpenBSD/pmax binaries.)
		Hardware devices may now register "tick functions" at
		specific cycle intervals in a generic fashion.
		All four channels of the dc serial controller device
		should now work; playing around with keyboard scan
		code generation when using the DECstation framebuffer.
		Making various (speed) improvements to the framebuffer
		device.
20031027	Playing around with the sii SCSI controller.
20031028	Minor fixes.
		Adding an SGI emulation mode (-G), and some ARCBIOS
		stuff, which SGIs seem to use.
		Adding getbitmap() to the DEC prom emulation layer,
		so some more -D x models become more usable.
		Adding a dummy 'ssc' serial console device for
		DECsystem 5400 emulation.
		Playing around with TURBOchannel stuff.
20031030	Minor fixes.
		Adding the sub instruction. (Not tested yet?)
		Sign-extending the results of multu, addi,addiu,
		add,addu,sub,subu,mfcZ.
		Adding a colorplanemask device for DECstation 3100.
		Fixed the NetBSD/pmax bug: I had forgotten to reset
		asid_match to 0 between tlb entry checks. :-)  Now
		userland runs nicely...
20031031	Fixing more bugs:  unaligned load/store could fail
		because of an exception, but registers could be "half
		updated". This has been fixed now.  (As a result,
		NetBSD/pmax can now run with any of r2000,r3000,r4000,
		r4400, or r5000.)
		Adding some R5K and R10000 stuff.  (Note: R5K is NOT
		R5000. Weird.)
		Adding dummy serial console (scc) for MAXINE.
		MAXINE also works with framebuffer, but there is no
		color palette yet (only black and white output).
20031101	Moving code chunks around to increase performance by
		a few percent.
		The opcode statistics option (-s) now shows opcode
		names, and not just numbers. :-)
		Fixing the bug which caused NetBSD/pmax to refuse
		input in serial console mode, but not in keyboard/
		framebuffer mode: the osconsole environment variable
		wasn't set correctly.
		Adding DEC PROM getchar() call.
		The transmitter scanner of the dc device now scans
		all four channels at once, for each tick, so serial
		output is (approximately) 4 times faster.
20031103	Adding a dummy BT459 vdac device, which does nothing
		but allows a PMAG-BA turbochannel graphics card to be
		used as framebuffer.
		Several DECstation machines (-D 2, 3, and 4) can now
		use TURBOchannel option card framebuffers as console,
		for output. (Keyboard input is still not implemented
		for those models.)  Only PMAG-AA (1280x1024x8) and
		PMAG-BA (1024x864x8), both using BT459 vdac, have
		been tested so far.
		Modifying the X11 routines so that several framebuffer
		windows now can be used simultaneously (if several
		graphics option cards are to be emulated concurrently).
20031104	DEC MIPSMATE 5100 (KN230) interrupts are shared
		between devices. I've added an ugly hack to allow
		that to work, which makes it possible to boot NetBSD
		into userland with serial console.
20031106	Removing the -S (symbol) option, as symbol files can
		now be given in any order together with other file
		names to be loaded.
		cookin tipped me about using (int64_t) (int32_t)
		casts instead of manually sign-extending values.
		Casting sometimes increases performance, sometimes
		decreases. It's tricky.
		Importing mips64emul into CVS.
20031107	Adding a generic ARC emulation mode.
		Increasing performance of the framebuffer by not
		updating it (or the XImage) if a write to the
		framebuffer contains exactly what is already in it.
		(This improves scrolling speed and initialization.)
		Adding initial MIPS16 support.
		Adding initial disk image support (-d command line
		option), but this will not be used until I get some
		kind of SCSI-controller emulation working.
20031108	Adding the first MIPS16 instructions: "move y,X",
		"ld y,D(x)", and "daddiu S,K" (but the last one
		doesn't work yet).
		Fixing the console environment variable for
		Enough of the 'asc' controller is now implemented
		to let NetBSD get past scsi disk detection when
		no disk images are used.
		DECstation machine type 2; both serial console and
		graphical console work now.
		Other X-windows bit-depths than 24 bits work now,
		but colors are still not correct in non-24 bit modes.
		Keypresses in X framebuffer windows are now
		translated into console keypresses. (Normal keys, but
		not cursor keys or other special keys.)
20031111	Adding support for X11 using non-24-bit output.
20031120	Adding X11 mouse event to emulated mouse event
		translation, but it's not tested yet.
		Trying to get more of the SCSI controller emulation
		to work.
20031124	Raw binaries can now be loaded into memory.
20031204	Adding srec binary support.
20031220	Adding some super-ugly arcbios emulation code.
		Making some progress on the SGI and ARC machine
		emulations.
20031222	SGI and ARC progress. Multiple CPUs are now added to
		the arcbios component tree (although NetBSD cannot
		actually use more than one).
20031228	Adding 'crime' and 'macepci' fake devices for SGI
		emulation.
		Finally implementing the cop0 'compare' register.
		Improvements to the ns16550 device, but it is still
		incomplete.
		SGI userland is now reached, but interaction is broken
		(due to the buggy ns16550).
20031229	Adding some more instructions: teq, dsllv
		Adding a Nintendo 64 emulation mode (skeleton).
		Adding R4300 and R12000 to the cpu list.
20031230	Adding bltzal, bltzall, bgezal, bgezall (not really
		tested yet).
		Fixing the 16550 serial controller device (by not
		supporting fifo, so in fact it emulates a 16450
		instead).  This causes NetBSD/sgimips to run nicely
		into userland, sysinst, and so on.
		Some ARC/RD94 interrupts seem to work ok now, but
		i/o interrupts are still not correctly implemented.
		NetBSD/arc userland is reached and can be interacted
		with, but there's no sysinst (?).
20040103	Trying to get some Irix stuff to work, but it's hard.
		Fixing some Cobalt/linux problems.
20040104	Adding a dummy 8250 device, so that Linux/sgimips can output
		console messages.
		Adding dmultu. (The same as dmult, so I'm not sure it's correct.
		Perhaps dmultu is correct and dmult is wrong...)
		Fixing a bug in unaligned load/stores of 64-bit values (a cast
		was needed).
		Linux/sgimips in 64-bit works a bit more than before.
		Adding simple (polled) input functionality to dev_zs.
		Making some progress on SGI-IP22 (IP32 still works best,
		though).
		Fixing the mc146818 clock device in ARC/NEC and SGI emulation
		modes, the year field was not correct.
		Adding a fake 'pref' instruction (lwc3).
20040106	Separating out memory.h from misc.h.
		Refactoring of a lot of small code fragments.
		The PCI bus device is now shared between Cobalt, SGI, and ARC.
		Support for RAM mirroring (dev_ram.c, not really tested yet).
		Ugly hack to select the largest of ELF string symbol tables,
		if there are more than one.
		Memory hole fix for ARCBIOS, and a fix for very large (>= 4GB)
		amounts of emulated RAM.
		TGA (DEC 21030) PCI graphics device. NetBSD/arc can boot with
		this card and use it as a framebuffer console.
20040107	Adding a fix (partly incorrect) to daddi, to allow Linux/sgimips
		to boot in 64-bit mode.
20040108	Fixing a sll/nop bug (rd==0 for nop, not sa==0 as before).
20040109	Trying to get an SGI-IP32 PROM image to boot.
20040110	Faking R10000 cache things.
		The PROM image boots, although it takes almost forever for it
		to realize that there is no keyboard.
		The 'gbe' SGI-IP32 graphics device works enough to display the
		Linux framebuffer penguin in the upper left corner :-)
20040111	-p and -P addresses can now be given as symbol names, not just
		numeric values.
		Experimenting with adding a PCIIDE (dev_wdc) controller to the
		Cobalt emulation.
20040120	Adding src/bintrans.c. No code yet, but this is a place for
		ideas to be written down.
		Increasing performance a little bit by inlining the check for
		interrupts (which occurs for every instruction).
20040124	Experimenting with pure userland (syscall) emulation.
20040127	Fixes for compiling under Solaris.
20040206	Some bintrans experiments.
20040209	Adding some simple Ultrix userland emulation syscalls.
20040211	Adding decprom_dump_txt_to_bin.c to the experiments/ dir.
		Adding a section to doc/ on how to use DECstation PROM dumps.
		Adding a hello world example to doc/ as well.
20040218	TURBOchannel slots that are empty now return a DBE exception,
		so that Ultrix and DECstation PROMs don't complain about
		broken TURBOchannel ROMs.
		Working some more on the machine-dependant interrupt stuff.
20040219	Trying out some Linux/DECstation kernels (semi-successfully).
20040222	YES! I finally found the bug that caused Linux/SGI-IP32 to only
		work on Alpha, not on 32-bit machines.  It was a shift left,
		probably done using 6 bits on alpha, 5 bits on 32-bit machines.
20040223	Some minimal DEC KN5800 progress; Ultrix prints some boot
		messages, detects 16 XMI R3000 cpus, and get a NULL panic.
		It's all fake, though, the CPUs don't actually work.
		Still, better than nothing :-)
20040225	An Ultrix OSF1 kernel with a ramdisk now boots :-)  (It was
		a problem with ultrixboot not giving the same arguments as
		NetBSD's boot program.)
20040225(later)	Fixing a bug in the DECstation dc serial device; digits 0-9
		were translated to numeric keypad 0-9, not the normal 0-9.
		(This caused Ultrix to print escape sequences instead of
		digits.)
20040226	Some progress on machine-dependant interrupt delivery
		for -D7 (Maxine) and -D4, and some more 'scc' serial
		controller featuers are implemented (but no interrupts/
		dma/keyboard/mouse stuff yet).
20040228	Progress on the scc controller; -D4 works in both serial
		console mode and with keyboard (graphical console), but no
		mouse yet.
20040301	SGI mace interrupts are now done using the new machine-
		independant interrupt system.
20040303	Fixing an R5900 bug; the lowest 6 bits have special meaning
		for coprocessor functions, not just 5 bits as on non-R5900
		CPUs. (This fixes a bug which caused NetBSD to crash.)
20040304	Adding enough (fake) DMA capabilities to the ioasic device
		to allow Ultrix to print boot messages in the -D3, -D4,
		and -D7 modes, and also print graphical console messages
		in -D4 and -D7 modes.
		-D11 (DEC5500) polled getchar added (to the 'ssc' device).
		Adding the 'madd' instruction (including R5900 weird stuff).
20040304(later)	Playstation 2's GIF can now copy 640x16 pixel chunks, allowing
		NetBSD to scroll up the framebuffer.  The cursor also works
		better now.
		Playstation 2 bootinfo RTC data should now be passed correctly
		to the running kernel.
		DECstation rtc year should be either 72 or 73, anything else
		will cause Ultrix to give a warning about invalid year.
20040306	Combining playstation2's dmac, interrupt, and timer devices
		into one (ps2_stuff).
		Adding some R5900 instructions: mfsa, mtsa, pmfhi, pmflo, por,
		lq, and sq.  (Most of them are just guesses, though.)
		Implementing my own XImage putpixel routine, which can be
		inlined... significantly faster than normal XPutPixel. :-)
20040307	Implementing the basic functionality of a "PMAG-CA" pixelstamp
		accellerated framebuffer device. Works with NetBSD and
		Ultrix, but no cursor or color support.
20040308	PMAG-CA, -DA, and -FA pixelstamps seem to work now.
		Adding a hack to allow a pmax/mach kernel to be loaded (it's
		a COFF file with 0 (!) sections).
		Initial test of bt459 + framebuffer cursor support.
20040309	Fixes/updates of dev_dec5800 and dev_ssc (and dev_decxmi) allow
		a KN5800 Ultrix-OSF1-ramdisk kernel to boot all the way into
		userland and be interacted with.
		The bt459 cursor should now look semi-nice, but it is still
		a bit fake.
20040310	Moving the DEC CCA stuff from src/machine.c into a separate
		device file (devices/dev_deccca.c).
		An ugly hack added to allow some more OSF/1 kernels (almost
		a.out, but without many of the header fields) to load.
20040314	Adding PMAG-JA and PMAG-RO (1280x1024 x 8-bit) TURBOchannel
		graphics devices. They work in Ultrix, but only monochrome
		and no cursor, because there are no ramdacs or such yet.
20040315	Pixelstamp solid fill now supports colors other than just
		zero-fill.
		Adding a (new) regression test skeleton.
20040321	Some really minor updates.
20040323	Fixes to allow SGI-IP20 and IP22 to work a bit better
		(aliased memory), and adding "private" firmware-like vectors
		to arcbios emul. An IP22 Irix kernel gets far enough to
		print an assertion warning (and then double panics). :-)
20040324	Adding a generalization hack to the SCC serial controller
		to work with SGI-IP19 (in addition to DECstations).
		Adding the 'sdc1' instruction.
		Some progress on various SGI emulation modes.
20040325	Minor updates.
20040326	Fixed a 'madd' bug (r5900). NetBSD/playstation2 now reaches
		userland correctly.  And a simple fix which allows NetBSD
		timer interrupts to be triggered; NetBSD uses T_MODE_CMPE
		(compare), while Linux uses _OVFE (overflow).
20040328	Linux on Playstation 2 boots a bit. The Playstation 2
		graphics controller has been extended to work better with
		NetBSD, and to include some Linux support as well.
		Some interrupt handling enhancements on Playstation 2,
		needed for Linux' dma.
		128-bit loads and stores (lq and sq) are allowed, although
		the top half of quadwords are not modified by other
		instructions. (Linux uses lq and sq.)
		Big-endian X Windows servers now display correct rgb color,
		not bgr as before.
20040330	Some minor updates to the documentation.
20040401	Adding a dummy ps2 OHCI device.
20040402	Progress on the asc SCSI controller.
20040406	Hack to allow ./configure, make to work on HP-UX B.11.00
		on HPPA-RISC, gcc 3.3.2. (Does not work with HP's cc.)
		More progress on the asc SCSI controller. Fixing INQUIRY,
		adding READ_CAPACITY, adding READ. Works a bit with NetBSD
		and some (but not all) Ultrix kernels, on DECstation type 2.
		Adding WRITE, SYNCRONIZE_CACHE.
		Mounting disks works in NetBSD :-)  It is a bit buggy,
		though. Or something else is buggy.
20040407	The bug is triggered by gunzip during NetBSD/pmax install.
20040408	Fixing a bug (non-nul-terminated string) which caused X11
		cursors to not display on Solaris.
		Unneccessary X11 redraws are skipped (removes some weird
		delays that existed before), and cursors are redrawn on
		window exposure. (The cursor functionality has been moved
		from dev_fb.c to x11.c.)
20040411	Fixing the DC7085 device so that Ultrix doesn't behave weird
		if both tx and rx interrupts occur at the same time.
		More advancements on the asc SCSI controller.
		More disk image filename prefixes are now recognized; c (for
		CD-ROM, as before), d for disk, b for boot device, r for
		read-only, and 0-7 for scsi id.
		Mounting disks works in Ultrix. Installing to disk usually
		crashes for various reasons, but an OSF/1 install gets
		relatively far (similar to the NetBSD/pmax install).
20040412	Trying to find the bug.
20040415	Finally found and fixed the bug; SCSI reads and writes
		(actually, any data in or data out) can be split up into
		multiple DMA transfers. That stuff was only partially
		implemented, and the part that was implemented was buggy.
		It works now. NetBSD/pmax and Ultrix 4.3 seems to like
		the SCSI stuff enough to install almost all the way.
20040415 (more)	Adding a hack which allows a host's cdrom device to be used as
		a cdrom device inside the emulator, eg /dev/cd0c.
		Making the cycle counter int64_t instead of long, as a 'long'
		overflows too easily on 32-bit machines. (The bug is still
		there, though.)
		I've now verified that a full NetBSD/pmax install can be done.
		If using a PMAG-AA graphics board, startx brings up X :-)
		mips64emul can be compiled inside NetBSD inside mips64emul,
		and it can run NetBSD in that environment. (I'm getting
		dizzy... :-)
20040417	Moving some coprocessor stuff from cpu.c to coproc.c.
20040424	Adding a BT455 vdac for PMAG-AA. Black and white are now
		rendered correctly in Xpmax.
		Adding colormap support to the BT459 device, for PMAG-BA.
20040425	Fixing a buffer length bug, which caused an Ultrix 4.5
		install to bug out on an i386 host.
20040429	FPU experiments.
20040502	More FPU experiments.
		Speedup for exception debug messages:  in quiet mode, debug
		messages were still evaluated, which took a relatively
		large amount of time.
20040503	Most FPU stuff fixed, but there is at least one known bug
		left; ps axu in NetBSD triggers it (ps loops forever).
20040504	A default install of Ultrix 4.5 succeeded! It boots up with
		a graphical login.
		Fixing the keyboard repetition bug (a lk201 "up" (release)
		scancode is now sent after every key).
20040505	Both CR and LF now produce the same lk201 scancode, so that
		pressing 'enter' works as expected in Ultrix.
20040506	Adding a vaddr to paddr translation cache, causing a speedup
		of perhaps 50% or more.
20040507	Fixing PMAG-BA color for Ultrix. (Ultrix relies on interrupts
		coming from the TURBOchannel slot to update the palette.)
20040508	Fixing cursor positioning for PMAG-BA.
20040511	Prints current nr of instructions per seconds, not only
		average, when using -N.
20040515	Some more bintrans experiments.
20040606	Adding ARCBIOS GetReadStatus() and Read().
		Adding some instructions: tlt, tltu, tge, tgeu, tne.
20040607	Adding the dsub instruction.
		Some minimal progress on SGI-IP30 emulation.
		Applying a patch from Juli Mallett to src/file.c (I'm not
		sure yet if it breaks or fixes anything).
		Some minor fixes for SGI-IP22 (such as faked board revision
		numbers).
20040608	ll/sc should now fail if any unrelated load/store occurs.
		Minor changes to the configure script.
		Adding some ifdefs around code which is not often used
		(the mfhi/mflo delay, and the last_used TLB experimental
		code); this might cause a tiny speedup.
20040609	Minor fixes.
20040610	Various minor SGI fixes (64-bit ARCS stuff, progress on the
		CRIME/MACE interrupt system, and some other random things).
20040611	More crime/mace progress, and some more work on pckbc.
		KN5800 progress: adding a XMI->BI adapter device; a disk
		controller is detected (but it is just a dummy so far).
20040612	Adding "dev_unreadable", which simplifies making memory
		areas unreadable. (NetBSD on SGI-IP22 no longer detects
		non-existant hpc1 and hpc2 busses.)
		Implementing rudimentary support for IP22 "local0" and
		"local1" interrupts, and "mappable" local interrupts.
		Some progress on the WDSC SCSI controller on IP22, enough
		to let NetBSD get past the disk detection and enter
		userland!  :-)
		The zs (zilog serial) device now works well enough to let
		NetBSD/sgimips be interacted with on IP22. :-)  (Though
		it is very ugly and hardcoded.)
20040613	IP32 didn't work last night, because there were too many
		tick functions registered. That has been increased now.
		Trying out NetBSD/sgimips 2.0 beta kernels. There are some
		differences compared to 1.6.2, which I'm trying to solve.
		Interrupt fixes for IP32: _serial and _misc are different.
		Separation of IP22 (Full-house) and IP24 (Guiness).
20040614	Modifying the memory layout for IP20,22,24,26 (RAM is now
		offset by 128MB, leaving room for EISA registers and such),
		and moving around some code chunks. This is not well
		tested yet, but seems to work.
		Moving parts of the tiny translation cache, as suggested
		by Juli Mallett.  It seems that the speedup isn't as
		apparent as it was a few weeks ago, though. :-(
		Speedups due to not translating addresses into symbol
		names unless the symbol name is actually printed.
		Added support for loading old big-endian (Irix) ECOFF
		kernels (0x60 0x01 as the first two bytes).
20040615 (late)	Adding enough SGI IP20 (Indigo) support to let NetBSD 2.0
		enter userland :-)  No interrupt specifics are implemented
		yet, so it hangs while doing terminal output.
20040618	Experimenting with the WDSC SCSI controller for IP20,22,24.
20040620	Adding a program which converts SGI prom dumps from text
		capture to binary, and some hacks to try to make such an
		IP22 PROM to work better in the emulator.
20040621	Removing the Nintendo 64 emulation mode, as it is too
		uninteresting to support.
		Adding SCSI tape device support (read-only, so far).
		Fixing a bug which caused the cursor to be corrupted if new
		data was written to the framebuffer, but the cursor wasn't
		moved.
20040622(early)	Finally! Making progress on the SCSI tape stuff; when going
		past the end of a file, automagically switch to the beginning
		of the next.
20040622(late)	Trying to track down the last SCSI tape bugs.
		Removing _all_ dynamic binary translation code (bintrans),
		starting from scratch again.
20040623(early)	Performing a general code cleanup (comments, fixing stuff
		that led to compiler warnings, ...).
		Disabling MIPS16 support by default, and making it a
		configure time option to enable it (--mips16). This gives
		a few percent speed increase overall.
		Increasing performance by assuming that instruction loads
		(reading from memory) will be at the same page as the last
		load.  (Several percent speedup.)
		Moving the list of kernels that can be found on the net from
		README to doc/.
20040624	Finally! I found and fixed the bug which caused 'ps', 'top',
		'xclock', and other programs in NetBSD/pmax to behave weird.
		Increasing performance by a few percent by running as many
		instructions in a row as possible, before checking for
		hardware ticks.
		When booting from SCSI tapes on DECstation, the bootstring
		now contains 'tz' instead of 'rz'.
		Adding a second ARC machine mode, "Acer PICA-61", -A2.
		Disabling the support for "instruction delays" by default
		(it has to be enabled manually in misc.h now, but is never
		used anywhere anyway).
		Other minor optimizations (moving around stuff in the
		cpu struct in misc.h, and caching cpu->pc in cpu.c).
		Separating the tiny translation cache into two, one for
		code and one for data. This gives a few percent speed
		increase.
20040625(early)	I think now is a good time for a "feature freeze",
		to let the code stabilize and then make some kind of
		first release.
20040625(later)	Adding a -v (verbose) command line option. If -v is not
		specified, the emulator goes into -q (quiet) mode just before
		it starts to execute MIPS code.
20040627	The configure script now adds -fomit-frame-pointer to the
		compile flags if the $CC seems to be able to handle that.
		Found and fixed a serious interrupt bug in BT459 (Ultrix'
		behaviour required a hack, which was incorrect), so
		performance for machines using the PMAG-BA framebuffer is
		now improved.
		For X11 bitdepths other than 8 or 24, a warning message
		is printed at startup.
		A number of other minor fixes, optimizations, updated
		comments and so on.
		Adding a BUGS file, a list of known bugs.
		Adding a minimal man page, doc/mips64emul.1.
20040628	Hacks for faking the existance of a second level cache
		(ARCBIOS and other places).
		An important fix for dc7085: tx interrupts should happen
		before rx interrupts, not the other way around as it was
		before. (This speeds up NetBSD boot on DECstation, and
		fixes a bug which Ultrix triggered on heavy keyboard input.)
		A couple of other minor fixes.
		Framebuffer fix: there was a bug which caused the rightmost/
		bottom pixel to sometimes not be updated, when running in
		scaledown mode. This is now fixed.
		Adding a small program which removes "zero holes" from
		harddisk image files.
20040629	More minor fixes.
20040629(later)	Adding -A3 (NEC RISCstation 2200) (this is similar to
		the 2250 model that NetBSD/arc can already boot all the
		way into userland and be interacted with), and -A4
		(Deskstation Tyne).
		Some more minor fixes.
20040630	Adding support for 15 and 16 bits X11 framebuffers,
		and converting from XYPixmap to ZPixmap (this fixes the
		problem of updates appearing in "layers" on some X
		servers).
		The pixels in the mouse cursor (for BT459) are now colored
		as the emulated OS sets them, although no transparency
		masking is done on the edges of the cursor yet. (In plain
		English:  the mouse cursor is no longer just a white solid
		square, you can actually see the mouse cursor image
		on the white square.)

==============  RELEASE 0.1  ==============

20040701	The -j option now takes a name, the of the kernel as passed
		on to the bootloader.  ("netbsd" is the default name.)
		Adding support to load bootstrap code directly from a disk
		image, for DECstation.  Both NetBSD/pmax and Ultrix boot
		straight of a disk image now, with no need to supply a
		kernel filename on the command line.  (Ultrix still needs
		-j vmunix, though, to boot from /vmunix instead of /netbsd.)
20040702	Minor bugfix (some new untested code for X11 keypresses was
		incorrect).
20040702(later)	Adding an ugly hack for CDROMs in FreeBSD; if an fread() isn't
		done at a 2048-byte aligned offset, it will fail. The hack
		tries to read at 2048-byte aligned offsets and move around
		buffers to make it work.
		Adding video off (screen blanking) support to BT459.
		Making a 0.1.1 release.