another 16 bytes off of BTX (and thus boot2):
- Compare against the value of %eax that is saved on the stack instead of
loading it into %eax (which requires saving the current %eax on the
stack).
- Use %ch to examine the keyboard flag state in the BIOS to see if
Ctrl-Alt-Del is pressed instead of %al so we don't have to save %eax on
the stack anymore.
MFC after: 1 week
BTX (and thus boot2):
- Don't bother saving %eax, %ebx, or %ecx as it is not necessary.
- Use a more compact sequence to load the base value out of a GDT entry
by loading the contiguous low 24 bits into the upper 24 bits of %eax,
loading the high 8 bits into %al, and using a ror to rotate the bits
(2 mov's and a ror) rather than loading the pieces in smaller chunks
(3 mov's and a shl).
- Use movzwl + leal instead of movl + movw + shll + addl.
- Use 'xchgl %eax,%foo' rather than 'movl %eax,%foo' for cases where
it's ok to trash %eax. xchgl %eax, foo is a 1-byte opcode whereas the
mov is a 2-byte opcode.
- Use movzwl rather than xorl + movw.
MFC after: 1 week
rather than just emulating mov cr0, eax. This fixes some Compaq/HP BIOS
with DMA (as the BIOS tried to read cr3 so it could translate addresses
if paging was enabled).
MFC after: 1 week
sync() and sync_fsync() without losing MNT_ASYNC. Add MNTK_ASYNC flag
which is set only when MNT_ASYNC is set and mnt_noasync is zero, and
check that flag instead of MNT_ASYNC before initiating async io.
- Make the PROBE_KEYBOARD option better resemble the -P option in
boot2, i.e., if keyboard isn't present then boot with both
RB_SERIAL and RB_MULTIPLE set.
Reviewed by: jhb
8k boundary with this program still.
text data bss dec hex filename
7925 4 4476 12405 3075 bootiic.out
so we have like 293 bytes left before we have to play games. There
may be ways to reduce that somewhat, but they start to be very board
specific.
changes in the future. This helps with getting started and to
overcome the really sucky level of granuality this timeout has in
getc. A timeout of 1 means 'wait until top of next second' rather
than 'wait for at least a second'.
fixes filesystem corruption when nextboot.conf is located after
cylinder 1023. The bug appears to have been introduced at the time
bd_read was copied to create bd_write.
PR: bin/98005
Reported by: yar
MFC after: 1 week
