Dec 072017
 
Permits joystick use in some games.
File JOYFORCE.ZIP from The Programmer’s Corner in
Category Games and Entertainment
Permits joystick use in some games.
File Name File Size Zip Size Zip Type
JOYFORCE.COM 11 11 stored
JOYFORCE.DOC 1920 908 deflated

Download File JOYFORCE.ZIP Here

Contents of the JOYFORCE.DOC file



Terry Bohning
11851 NW 37 Place
Sunrise, FL 33323

Compuserve [71036,1066]
original: 11/4/88


Rev. 1: 11/8/88
Corrected an error in the DEBUG source
was:
or byte ptr [0411],16 ;game port indicator is bit 4 of high byte
changed to
or byte ptr [0411],10 ;game port indicator is bit 4 of high byte
since DEBUG uses hex, not decimal.

Note that JOYFORCE.COM was OK, just the doc was wrong.



Force System Recognition of Joystick

Recently I fired up my AT clone's game port for the first time since
I purchased it and discovered that Striker, one of my favorite
public domain games, would not work with a joystick.

After quite a few hours of work, I found that the DOS
Equipment Check Call (INT 11H) was saying that there was
no game port! I examined my old XT BIOS source code and
found that the equipment flag is a word stored at 00:0410.
Bit 12 of the word signifies whether there is a game port
or not.

The BIOS sets this at power up based upon whether there is a
stick attached to the port or not. So if you boot up without
your stick attached, you don't have a game port.

Well, in my case, it didn't seem to matter whether the stick
was there at power-up or not, it just didn't work.

I keyed the program shown below in under DEBUG (minus
the comments of course) , saved it as JOYFORCE.COM
and now Striker works fine.

C>DEBUG
-a100
xor ax,ax ;equipment flag is in segment 0
mov ds,ax ;set Data Segreg to 0
;high byte of equipment flag is at 0x411
or byte ptr [0411],10 ;game port indicator is bit 4 of high byte
int 20 ;terminate program

-rcx
CX 0000
:0b
-njoyforce.com
-w
Writing 000B bytes
-q
C>
/********************* EOF *************************/


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