21 Jun
2001
21 Jun
'01
3:05 p.m.
On Thu, 21 Jun 2001, George Currie wrote:
Two different concepts. The DOS tech refs are
refering to the values
to place in ah (I think, or was it al?) before making a DOS or BIOS
int call. This is all pre-DLL days. Richard is referring to the
ordinal number within a DLL to reference a specific function located
in the DLL.
He is referring to the number reported by his disassembler that is
disassembling the Windoze program (into DOS compatible assembly language).
The value placed in AH IS for the purpose of referencing a specific
dunction located in the MS-DOS DOS function handler (INT 21h).
Not all functions in a dll have their names exported
and
sometimes the only way to get to them is by ordinal number. This is
one way that M$ creates 'value added' to their software by utilizing
these undocumented calls.
And there were/are a few undocumented functions in MS-DOS, such as #34h,
and INT 28. And don't forget the "network redirector" (since 3.10) that
is needed even to use MS's CDROM drivers.
--
Fred Cisin cisin(a)xenosoft.com
XenoSoft http://www.xenosoft.com
PO Box 1236 (510) 558-9366
Berkeley, CA 94701-1236