collapseos/blk/089

Initialization sequence

On boot, we jump to the "main" routine in B289 which does
very few things.

1. Set SP to PS_ADDR and IX to RS_ADDR
2. Sets HERE to SYSVARS+0x80.
3. Sets CURRENT to value of LATEST field in stable ABI.
4. Execute the word referred to by 0x04 (BOOT) in stable ABI.

In a normal system, BOOT is in core words at B396 and does a
few things:

1. Initialize all overrides to 0.
2. Write LATEST in BOOT C< PTR ( see below )
3. Set "C<*", the word that C< calls to (boot<).        (cont.)