Subject:  pm2 proms
changes to the user interface -
1. can boot any type file from any medium.  (this involves a
   kluge for type 0407 files:
   if the load address is one of 0x400, 0x1000, or 0x2000
   and the entry point is given as 0, the program is entered
   at the load address.  previously 0407 files were treated
   differently depending on whether they came from the net
   or from the disk; now they are treated differently based
   on the entry / load address in the header).
2. the "ls" feature of "b xxx/*" is separated into a "ls xxx"
   command.
3. code is present to boot from proms. "boot p.XXXX" where
   XXXX is the mem address.
4. "help" has been expanded.  specific help is available for
   certain commands (eg "boot").  incorrect messages fixed.
   help added for previously undocumented commands.
5. reorganized debugger code.  display uarts by "du N" instead
   of "es N".  display special regs by "xC" instead of "es C".
   this makes it more like examining other regs.
6. changed printouts to be more consistent.
7. "n file" and "boot n:file" both work.
8. "g.N:file" instead of g "file N" (IEEE 488 boot).

bug fixes -
1. adventure - "read" didn't get enet address
2. tape boot didn't recognize some cpio tapes
   also new bugfixes from chase
3. net boot got returned name wrong
4. debugger.c had an off-by-one array reference
5. both netboot and diskboot treated '*' sloppily
6. all drivers were sloppy with ':', eg "b /vmunix:new"
7. disk driver had "old" code to reset excelan
8. certain boot features probably wouldn't have worked.
   calling nboot at hi priority.
9. net driver now checks both new and old addresses for enet board.
10.wait488 now checks for present (instead of bus error).
11.net driver now accepts both DST_END and DST_OLDEND; DST_DATA and
   DST_OLDDATA types.
11.termulate/download didn't work.
   also new bugfixes from gb
12."harmless" bugs in tape driver and disk driver
   mf (md) driver now sets up fake label correctly.

structural changes -
1. "irispm2.c" split into a new directory containing one
   file for each individual command.  (to improve modularity).
2. reorganized (replaced) parser, command switch, and help code.
   (also for modularity).
3. reorganized (replaced) debugger code.
4. reorganized (replaced) much of boot code.
   separated "downloading" from "driver" functions in all cases.
   minor bugfixes.
5. added "library" routines:
   delay(n) delays approximately n milliseconds.
   newline() calls printf("\n");
   extern char z[] is a null string.
   isnum(string,ptr) returns whether string is a numberstring
	and stores its value in *ptr.
   readargs(argcp,argvp) reads a line and passes back argc and argv.
   strlcpy(s,t,l) copies from src to tgt but limited by l
   atoci(string) interprets string as a c-style number but default hex
6. use "ctype.h" where possible.
7. use "blt" everywhere instead of "bcopy".
   use "clear" everywhere instead of "nxzero", "bzero", etc.
8. thus various files are superseded...
9. boot/, dboot/ --> dev/
   sys/, pm2/ --> gen/, pm2/ except for graphics
10.hacked dev/*.[ch] to use mbmalloc() and vtop() consistently.
11.moved stack+bss+i/o to LAST virtual chunk (and physical chunk);
   allowing large programs to load.
12.scanning mem now restores old contents to probed mem.
   clearing mem now uses a window - this allows maximal phys mem
   to be configured.
13.various routines now use a moving window instead of mapping
   all of mem.  unused virtual addresses are unmapped at startup.
14.merged gl1, gl2 into a common interface switched at boot time.
15.disk drivers changed to be ignorant of fs type.
16.more "harmless" bugs fixed in ip driver
17.^S / ^Q work
18.prints out 68010 on error messages instead of 68000 where
   appropriate
19.fixed dutranslate - capslock affects only alpha keys!
20.fixed autoboot from md: disk
21.fixed (hope) delays to be consistent!
22.fixed rs170 initial clear
23.eliminated !* split screen
24.fixed bug in handling <break> from user program.
25.added code to disable intr from ikon.
26.added efs support
