External interface

LILO \ is able to receive its command line from a program that is booted before it. This externally provided command line is only used if the user does not use the normal mechanism to invoke the boot prompt. The following register contents are expected:
DL
contains the value 0xFE.
ES:SI
points to the string ``LILO''. The string must be in upper case and no terminating character is needed. The string must not cross segment boundaries, i.e. <#513#> SI<#513#> must be below 0xFFFD.
ES:BX
points to a NUL-terminated string that is used as the command line. This string has a maximum length of 78 characters (not including the terminating NUL) and must not cross segment boundaries.
There are two values of the externally provided command line that have a special meaning:
  • an empty string (<#516#> ES:BX<#516#> points to a NUL byte) is interpreted as a request to enter the boot prompt and to accept keyboard input.
  • a string that consists only of blanks is interpreted as a request to boot the default boot image.
LILO \ can also obtain the default command line from the map file. It is only used if no externally provided command line is available.