modules:

	a real-mode control program (code/data segments)
	a 16-bit protected mode interface section
	a 32-bit flat program arena, loaded from a.out file

control assist functions:

	All control assist functions use linear addresses, not segment addresses!

word32	peek32(vaddr)
	poke32(vaddr, word32)
word16	peek16(vaddr)
	poke16(vaddr, word16)
word8	peek8(vaddr)
	poke8(vaddr, word8)
	memget(vaddr, void *, length)
	memput(vaddr, void *, length)

VCPU structure: (global var contains pointer to current VCPU)

	it's a TSS with extra stuff at the end
	One TSS for control program state (unused but required)
	One TSS for arena program state
	others for other stuff

	Page faults cause task switches; other are regular interrupts
	that jump through a TSS later

Interface routines:

	go32 - VCPU contains state to jump into
	  returns for exceptions and interrupts

GDT entries:

	<zero>
	GDT
	IDT
	control code (use16)
	control data (use16)
	interface code (use32)
	interface data (use32)
	core memory (use32)
	arena code (use32)
	arena data (use32)
	control TSS state
	arena TSS state
	other TSS state (for convenience functions)
	page fault TSS state

Mappings:

	arena segments start at 0x10000000
	core remapped to 0xF0000000 (0xE0000000 to arena)
	VGA 256c paging at 0xE0000000 (0xD0000000 to arena)

Page management:

	bit-per-physical page map for free list
	PT entry contains state and location information:
	 * present (inc. dirty, accessed)
	 * uninitialized
	 * paged to disk (includes block address)
	bit-per-page map for disk swap free list

interrupts:

	int 21,AH=4A
		AL=0 brk(ebx) returns old brk in eax
		AL=1 sbrk(ebx) returns old brk in eax

	int 21,AH=FF - turbo assist.  Func in AL, parms (ebx,ecx,edx) ret eax
	1: creat
	2: open
	3: fstat
	4: gettimeofday
	5: settimeofdat
	6: stat
	7: system

	int 10, AH=FF - set video mode
	0: 80x25 text
	1: default text
	2: text CX cols by DX rows
	3: biggest text
	4: 320x200 graphics
	5: default graphics
	6: graphics CX width by DX height
	7: biggest non-interlaced graphics
	8: biggest graphics