diff options
| author | jhb <jhb@FreeBSD.org> | 2006-09-28 19:42:10 +0000 |
|---|---|---|
| committer | jhb <jhb@FreeBSD.org> | 2006-09-28 19:42:10 +0000 |
| commit | ba03f04b1432aba8c3c760cce5119eca140b0025 (patch) | |
| tree | f865b1adae388a7939e1799dfbe0b680301e566c /sys/boot | |
| parent | 79660d10e40a475a31576a6b4ffd3ba1ec7ad31f (diff) | |
| download | FreeBSD-src-ba03f04b1432aba8c3c760cce5119eca140b0025.zip FreeBSD-src-ba03f04b1432aba8c3c760cce5119eca140b0025.tar.gz | |
Tweak the code to handle intercepting BIOS calls to int 0x15 to shave
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
Diffstat (limited to 'sys/boot')
| -rw-r--r-- | sys/boot/i386/btx/btx/btx.S | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/sys/boot/i386/btx/btx/btx.S b/sys/boot/i386/btx/btx/btx.S index 52c0e5a..c8955a5 100644 --- a/sys/boot/i386/btx/btx/btx.S +++ b/sys/boot/i386/btx/btx/btx.S @@ -657,23 +657,16 @@ v86intn: lodsb # Get int no cmpb $0x19,%al # is it int 19? je reboot # yes, reboot the machine cmpb $0x15,%al # is it int 15? - jne v86intn.3 # no, skip parse - pushl %eax # stash EAX - movl 0x1c(%ebp),%eax # user's saved EAX - cmpb $0x87,%ah # is it the memcpy subfunction? - jne v86intn.1 # no, keep checking - popl %eax # get the stack straight - jmp int15_87 # it's our cue -v86intn.1: cmpw $0x4f53,%ax # is it the delete key callout? - jne v86intn.2 # no, handle the int normally - movb BDA_KEYFLAGS,%al # get the shift key state - andb $0xc,%al # mask off just Ctrl and Alt - cmpb $0xc,%al # are both Ctrl and Alt down? - jne v86intn.2 # no, handle the int normally - popl %eax # restore EAX - jmp reboot # reboot the machine -v86intn.2: popl %eax # restore EAX -v86intn.3: subl %edi,%esi # From + jne v86intn.1 # no, skip parse + cmpb $0x87,0x1d(%ebp) # is it the memcpy subfunction? + je int15_87 # yes + cmpw $0x4f53,0x1c(%ebp) # is it the delete key callout? + jne v86intn.1 # no, handle the int normally + movb BDA_KEYFLAGS,%ch # get the shift key state + andb $0xc,%ch # mask off just Ctrl and Alt + cmpb $0xc,%ch # are both Ctrl and Alt down? + je reboot # yes, reboot the machine +v86intn.1: subl %edi,%esi # From shrl $0x4,%edi # linear movw %dx,-0x2(%ebx) # Save flags movw %di,-0x4(%ebx) # Save CS |
