* Update documentation to match new implementation.

	* Make an sparc port to not remove previous functionality.

	* Add two new base instructions to help dynamically typed
	languages, that use two result registers and two argument
	registers, implementing multiplication and quotient+remainder
	return from division. Alternatively, can add branch codes
	for multiplication that overflows (and reverse for no
	overflow) and division with zero remainder or non zero
	remainder.
	Suggested names for now are "qmul" and "qdiv", with "r"
	and "i" variants, and possibly unsigned version. Branches
	would use "bo" and "bx" prefix.

	* Convert retr to an actual node, otherwise, code like:
	movi %r0 1
	divr %r1 %r2 %r3
	retr %r0
	will fail in x86 because, besides "divr" telling it clobbers
	%rax (r0) it ends being ignored because retr is a noop there
	(removed "mov %rax,%rax" expansion) and the code checking for
	live registers ends up not knowing about %rax being live after
	the "divr". This affects only x86.

	* Validate that divrem in jit_x86-cpu.c is not modifying
	the non result arguments. This is not verified by clobber.tst,
	as it only checks registers not involved in the operation
	(because it does not know about values being set as input
	for the the operation).