Shaved around 100 bytes off vsprintf.o. It's now 50 bytes smaller than
the old implementation and provides much more conformant semantics,
including the ability to return the number of characters that would have
been printed to the string had the buffer been big enough. (iSCSI needs
this functionality).
At least cope with "%llx" by reading the correct-sized va_arg from the
stack, even if we don't yet print it out.
At some point, vsprintf() needs to be fixed up so that it can correctly
cope with limited-sized buffers (i.e. vsnprintf), long longs, and
standard format specifiers (e.g. "%04x"). We should also remove the
special types (MAC addresses and IP addresses). This would then enable
us to use gcc's ability to type-check printf format strings.
Use .text16.data section with "aw" attributes, to avoid section type
conflicts when placing both code and data into .text16.
Add __from_{text16,data16}.
Preserve the whole of %esp across prot_call(). We have to split this
between the low half stored in the static variable rm_sp, and the high
half stored on the prot_call() stack, because:
Just using the stack would screw up when a prot_call()ed routine
executes a real_call(); it would have no way to find the current top of
the RM stack.
Extending rm_sp to rm_esp would not be safe, because the guarantee that
rm_sp must return to the correct value by the time an external
real-mode call returns applies only to %sp, not to %esp.
Add infrastructure to support access to .data16 (and .text16) variables
from protected-mode code.
Set up %ds to point to .data16 in prot_to_real, so that code specified
via REAL_EXEC() and friends can access variables in .data16.
Move most real-mode librm variables from .text16 to .data16.