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avcaballero



Joined: 02 Feb 2004
Posts: 192
Location: Madrid - Spain
avcaballero
I'm trying to do an interrupt handler and i need make a far procedure, something like this:

NuevaInt21h:
STI
PUSHF
DB 9Ah
OldInt21h DD 0
CLI
INC BYTE [NumTeclas]
IRET

But "LDS DX, OldInt21h" fails me. How can do it?

Thank you
Post 23 Jun 2005, 13:55
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Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 7724
Location: Kraków, Poland
Tomasz Grysztar
It should be:
Code:
LDS DX,[OldInt21h]    


Also I'd prefer to not use DB to define opcodes:
Code:
STI
PUSHF
CALL FAR DWORD 0:0
LABEL OldInt21h DWORD AT $-4
CLI    


Last edited by Tomasz Grysztar on 23 Jun 2005, 14:05; edited 2 times in total
Post 23 Jun 2005, 13:58
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
privalov: now i'm confused. why "dword" ?
Post 23 Jun 2005, 14:00
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Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 7724
Location: Kraków, Poland
Tomasz Grysztar
16-bit far pointer is DWORD, 32-bit far pointer is PWORD.

Also definitions like this are correct:
Code:
ptr16 dd 0:0
ptr32 dp 0:0    

where first 0 is 16-bit segment/selector and second 0 is 16/32-bit offset.
Post 23 Jun 2005, 14:01
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