Date: Tue, 7 Nov 2000 13:15:25 +0200 (IST) From: Eli Zaretskii X-Sender: eliz AT is To: djgpp AT delorie DOT com Subject: Re: int 21h and assembler In-Reply-To: <8u7ft0$6r3$1@nnrp1.deja.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: djgpp AT delorie DOT com Errors-To: nobody AT delorie DOT com X-Mailing-List: djgpp AT delorie DOT com X-Unsubscribes-To: listserv AT delorie DOT com Precedence: bulk On Mon, 6 Nov 2000 danspam2000 AT my-deja DOT com wrote: > I am quite new to assembler, but i need to service a hardware interrupt > very quickly, so have had to code using inline assembler code. > > The problem i have is that i can't seem to get a definitive answer > about how to protect the service routine in memory. I think that i > should use int 21H, but some books and lists say to use service 48 and > some say 49, and one said 27! Also, i am not sure exactly what i need > to pass, and using which registers (some say dx and some say bx), do i > need to pass a segment or an offset, or both? This is all explained in section 18.9 of the DJGPP FAQ list, which I suggest to read. Section 18.11 is also a recommended reading.