Re: Caling custom interrupt without using "call interrupt"

2021-01-03T15:19:58-05:00

That's probably more an ASM question than a QB question. Anyway, a while back Hans Lunsing wrote a replacement for Call InterruptX in assembly so QBasic 1.1 could also support interrupts. The code is available right here. I don't know much about assembly but it should be possible to retrieve the instructions he used via the hexadecimal code in DATA and see how he managed to pull it off.

Code:

DATA 55,8B,EC,8B,5E,0C,8B,17,0A,F6DATA 74,07,C7,07,FF,FF,E9,A7,00,8BDATA 5E,06,8B,1F,2E,88,97,77,00,32DATA C0,80,FA,25,74,05,80,FA,26,75DATA 02,0C,02,50,1E,06,56,57,9C,8BDATA 76,0A,80,FA,20,7C,05,80,FA,30DATA 7C,0A,81,7C,08,FF,FF,74,03,8BDATA 6C,08,8B,44,0E,25,D5,0F,50,8BDATA 04,8B,5C,02,8B,4C,04,8B,54,06DATA 8B,7C,0C,FF,74,0A,81,7C,12,FFDATA FF,74,03,8E,44,12,81,7C,10,FFDATA FF,74,03,8E,5C,10,5E,9D,CD,00DATA 55,8B,EC,9C,83,C5,0E,F6,46,FEDATA 02,74,02,45,45,1E,56,8E,5E,FCDATA 8B,76,08,89,04,89,5C,02,89,4CDATA 04,89,54,06,8F,44,0A,89,7C,0CDATA 8F,44,10,8C,44,12,8F,44,0E,8FDATA 44,08,F6,46,FE,02,74,02,44,44DATA 9D,5F,5E,07,1F,58,5D,CA,08,00

Statistics: Posted by MikeHawk — Sun Jan 03, 2021 3:19 pm

Caling custom interrupt without using "call interrupt"

2021-01-02T19:19:41-05:00

I was fiddling around with webserv.bas from http://rubbermallet.org/software/webserv.html and am still doing so especially now that it breaks down after each HTTP request. I could partly blame some web browsers because they like to do prefetching.

So now I want to make the software even faster by replacing his routines to "call interrupt" with my own that will use "call absolute" so it works in all versions of DOS Qbasic. (1.1, 4.0, and 4.5).

The problem I have is the assembly language itself. To call an interrupt one would use:

Code:

Int xx

where xx is a fixed interrupt number, but I want to pass a variable to it instead, so I can make a simpler assembler routine like this for Qbasic:

Code:

PUSH BPMOV BP, SPMOV BX, [BP+06h]Int BLPOP BPRETF

and then execute it in Qbasic like this:

Code:

d$="(above assembly in binary code)"dseg%=varseg(d$)doff%=sadd(d$)def seg=dseg%call absolute(intno%,doff%)def seg=0

But the problem is nasm (the assembler compiler I use) complains about the INT line because it doesn't want to accept a variable as an interrupt number.

How do I go about fixing this?

Statistics: Posted by mikefromca — Sat Jan 02, 2021 7:19 pm

Pete's QBASIC Site

Re: Caling custom interrupt without using "call interrupt"

Caling custom interrupt without using "call interrupt"