We expect to use Linux kernel coding style, minus the indentation
level.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Since we might be having COM32 and COM32R in the same filesystem, do
check for the appropriate COM32R magic before doing anything else.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Try to HLT the processor during idle.  All the events we care about
should have interrupts associated with them, except possibly the
serial console.  Try to deal with the serial console by waiting some
time before going into HLT, and giving the user the option of enabling
the serial console interrupt, on the assumption that the BIOS will
simply IRET.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

When entering 16-bit PM after shuffle and boot, we might as well
do so sanely.  Specifically, set up the data segments so that they
match the code segment, generating a 16-bit "tiny" model environment.

This makes it a lot saner to bootstrap a proper PM environment from
there if that is what the user intends.  For the presumably more
common case of RM entry, it won't do any harm, and it's only a handful
of additional instructions.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Change MENU SAVE to be a cascading default that can be reverted with
MENU NOSAVE.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Remove stay parenthesis in syslinux.txt

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

Clarify that the CS.base restriction is a prescription of
compatibility, and not something that the ABI handles transparently.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>