GEMDOS Device I/O and Process Control
*** Program equates
conterm ** $484
scr_dump = $502
*** Program starts here
.text
*** Branch to install code at end of program
start:
bra.w
init
*** The ID here lets us check to see if the resident program was
*** already installed once, so you don't try to do it again if the
*** program is run more than once.
ID:
.dc.b 'TOGGLE'
*** This code is executed only when Alternate-Help is pressed.
*** you're in supervisor mode here.
toggle:
movem.1
move
ori.w
eori.b
keyclr:
clr.w
move.w
trap
addg. 1
move
movem.1
rts
d0-d7/a0-a7,-(a7)
sr,-(a7)
#$700,sr
* save registers
* and status register
* bump the Interrupt Priority Level
* to 7 (so you don't get interrupted)
|l,conterm * bit 0 of conterm controls key click
* clear keyboard so you don't repeat
* clear all keyboard shift bits
* shift bits function
* call BIOS
* clean stack
-(37)
#$B,-(a7)
#$D
#4,a7
(a7)+,sr
(a7)+,d0-d7/a0-a7
* restore status register
* restore rest of registers
* and end toggle routine
**** Initialize and install routine— this is only done once
**** and then this code is thrown away
init:
*** Print sign-on message
pea msgl
move.w #$9,-(a7)
trap #$1
addg.l #6,a7
* push address of sign-on string
* Cconws
* call GEMDOS
* pop args from stack
*** Switch to Supervisor mode to read protected memory
clr.l -(a7)
move.w' #$20,-(a7)
trap #$1
addg.l #6,a7
move.l dO,oldstack
* switch to super mode, same stack
* Super function
* call GEMDOS
* clean up stack
* save old stack address
*** Check to see if this program has been installed once.
*** If it hasn't, install it. If it has, end
movea.1
subg.1
lea
move.w
checkid:
cmpm.b
bne.b
dbf
move.l
move.w
trap
addg.1
scr_dump,aO * get screen dump vector
#6,a0 * move back 6 characters
ID,al * check to see if you're already installed
#$5,do * 6 letters in ID
(a0)+,(al)+ * compare ID to resident program
install * if ID doesn't match, install toggle
do,checkid * if it does match, ...
oldstack,-(a7) * push old stack address
#$20,~(a7) * out of super mode
#$1 * call GEMDOS
#6,a7 * clean stack
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