;   »»»»»»»»»»»»»»»»»»»»»»»»»» Virus Detection Program ««««««««««««««««««««««««««««««
;
; This is a little detection program that I wrote.  All it does is 
; scan through the programs on the calc and looks for one called 'VIRUS'
; If it is there it tells you, if not then it also tells you.
; I tried to explain as much stuff as possible, if you don't understand anything
; just email me and I'll try to help you out.  Please understand that I am still
; learning also.  ;-]
;
; ______________________________________________________________________________
;
; »» You are free to use this but a little thanks to me would be appreciated. «« 
; ______________________________________________________________________________
;
;
; Please send all questions to Jimmy Conner at »»TIMagic@yahoo.com««
; http://www.angelfire.com/tx/timagic/       TI-82/83 Page

.NOLIST				; Required
#define equ .equ			; Include these so the program will compile right
#define EQU .equ			;  ''       ''  ''  ''    ''    ''     ''    ''
#define END .end			;  ''       ''  ''  ''    ''    ''     ''    ''
#define length 8265h		; My var for the length of the program name
#define prog 8266h		; My var for if it found the program or not
#include "ti83asm.inc"		; Include these so the program will compile right
#include "tokens.inc"		;  ''       ''  ''  ''    ''    ''     ''    ''
.LIST					; Required
.org 9327h				; ALL TI-83 Programs start here in memory


	call	_clrLCDFull 			; Clear Screen	
	call	_runIndicOff			; Turns off Runindicator
	set 	textinverse, (iy+textflags)	; Toggle text inverse on
	call	_homeup				; Goto 0,0 of screen
	ld	hl,timagic				; Load String Jimmy's AntiVirus 
	call	_puts					; Output it to screen
	res 	textinverse, (iy+textflags)	; Reset text inverse (off)
	call 	_newline				; New Line
	call 	_newline				; New Line
detect:
	ld	hl, (progptr)	; Start here to look for programs`
	ld	a, 0		; You have to load it into 'a' before into an address
	ld	(prog), a	; Do this so later we'll know if it found it
startdetect:
	ld	a,(hl)	; Get the type
	and	%00011111	; need to mask out bits 0-4
	cp	$06		; Is it a protected program?
	jp	z, program	; If so jump to the program
	cp	$05		; Is it a program, but not protected?
	jp	z, program	; If so jump to the program
	cp	$01		; Is it a list?
	jp	z,list	; If so jump to the list loop	
	cp	$0D		; Is it a complex list?
	jp	z,list	; If so jump to the list loop
	ld	a, (prog)	; Reload the 'found it' variable
	cp	1		; Did it find it?
	jr 	z, pf		; Yes
	jr	nz, pnf	; No
	ret			; Nothing left so quit
program:
	dec	hl		; move to ptr (skip var type)
	dec	hl		; move past fisrt ptr
	dec	hl		; move past second ptr to the name length
	push	hl		; Store it for later
	ld	a, (hl)	; Put the length in 'a'
	ld	(length), a	; Store the length for later
	cp 	5		; Five letters in name?
	jp	nz, nextprog	; If not then it isn't it so goto the next program
				; OK we know that it has five letters so now will
				; the letters be the same?
	dec	hl		; First letter
	ld	a, (hl)	; Load the first letter
	cp	56h		; V?
	jp	nz, nextprog	; Nope isn't right letter
	dec	hl		; Second letter
	ld	a,(hl)	; Load the second letter
	cp	49h		; I?
	jp	nz, nextprog	; Nope isn't right letter
	dec	hl		; Third letter
	ld	a,(hl)	; Load the third letter
	cp	52h		; R?
	jp	nz, nextprog	; Nope isn't right letter
	dec	hl		; Forth letter
	ld	a,(hl)	; Load the forth letter
	cp	55h		; U?
	jp	nz, nextprog	; Nope isn't right letter
	dec	hl		; Fifth letter
	ld	a,(hl)	; Load the fifth letter
	cp	53h		; S?
	jp	nz, nextprog	; Nope isn't right letter
	ld	a, 1
	ld	(prog), a	; It found it if it got this far so store 1 to 'prog'
	jp	nextprog	; let it finish searching
pf:				; This place is were it outputs that it found it.
	ld	hl, progfound	; Load the text
	call	_puts			; Output it
	call	_newline		; Go to the next line
	ld	hl, inprogram	; Load the text
	call	_puts			; Output it
	call	_newline		; Go to the next line
	set 	textinverse, (iy+textflags)	; Toggle text inverse on
	ld	hl, VIRUS		; Load the text
	call	_puts			; Output it
	res 	textinverse, (iy+textflags)	; Toggle text inverse on
	ret
pnf:				; This place is were it outputs that it didn't find it.
	set 	textinverse, (iy+textflags)	; Toggle text inverse on
	ld	hl, prognotfound	; Load the text
	call	_puts			; Output it
	res 	textinverse, (iy+textflags)	; Toggle text inverse on
	call	_newline		; Go to the next line so when it displays 'DONE'
	ret
nextprog:
	pop	hl 		; Go back to the length
list:
	dec	hl		; lists enter here to be skipped
	dec	hl		; Skip the last part of the pointer
	dec	hl		; should be at the length
	ld	b, (hl)	; load that so we can loop past it
list2:
	dec	hl		; dec hl to goto next letter in name
	djnz	list2		; loop until the end of the name
	dec	hl		; should be at the next item
	jp	startdetect ; go find next item
timagic:
		.db	"Jimmys AntiVirus", 0	; 0 terminated string for display
Progfound:
		.db	" Virus detected", 0	; 0 terminated string for finding the program
inprogram:
		.db	" In the Program", 0	; 0 terminated string for finding the program
virus:
		.db	"     VIRUS      ", 0	; 0 terminated string for finding the program
prognotfound:
		.db	" No Virus found ", 0	; 0 terminated string for not finding the program
.end
END

;
; You have to remember that when you search for a list that the last bit in 
; the name is the formula number, if there isn't one then it is 0.  So if you  
; calculate the length of the name in your head, add 1 and check for a zero
; at the end of the name.
;
; »»»»»»» TIMagic@yahoo.com  «««««««