; L6NEW.asm - new Reslt Subr, better

; management of data locations

; Code for Lab 6 on the EVB

; Must be modified to test on THRSim11

; Program prints a message to screen,

; accepts a keypress, and calculates

; reaction time in SWI ISR.

;

PutC = bfd3 ;assign labels to the custom

GetC = bfd0 ; instruction address locations

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IRQ = ef

SWI = f5 ; You may use these

RTI = ec ; or make your own

TCNT = 100e

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org c00a

db 0a,0d

db 72,65,61,64 ; Message data

db 79,28,79,20

db 6f,72,20,6e

db 29,3f,00

org c200

Main: lds #dfff ; initialize the stack at bottom of

; memory

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; Set jump table for

; Interrupt Svc. Routines

; here

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clr c000 ; initialize test data locations

clr c001

clr c002

clr c003

First: ldy #c000 ; initialize data pointer

Load: sty c006

cli ; enable interrupts

ldx #c00a

Send: ldaa 0,x ; load A with ASCII for Message

beq Wait

psha ; push the contents of A onto the stack

inx

jsr PutC ; Send message to screen

bra Send

Wait: jsr GetC ; use GetC to detect a key press

bcc Wait

pula ; when a key is pressed load the ASCII vale into A

psha ; put it back on the stack

jsr PutC ; dump the ASCII character for the key to the Monitor

cmpa #79 ; check to see if the key press was "yes"

beq Next

cmpa #6e

beq End

bra Load

Next: clr 0,y

clr 1004

com 1004 ; blank the LEDs

jsr DelVar ; Wait for a variable time

ldx #1000

bset 24,x,40 ; Enable RTI interrupt

Port: com 1004 ; Shine LEDs

Spc: jsr GetC ; Wait for spacebar press

bcc Spc

pula

cmpa #20

bne Spc

psha

ldx #0a0d

pshx

jsr PutC

jsr PutC

swi ; If Spacebar press, Interrupt

ldy c006

iny

cpy #c004

bne Load

jmp First

End: ldaa #65

psha

ldx #6279

pshx

ldx #0a0d

pshx

jsr PutC

jsr PutC

jsr PutC

jsr PutC

jsr PutC

jsr DelVar

swi

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DelVar:

; make your delay subroutine here

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IRQSvc:

; make your IRQ ISR here

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RTISvc:

; make your RTI ISR here

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SWISvc:

;make your SWI ISR here

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HtoA:

; Convert 8-bit ASCII to 4-bit Hex

; input registers: none - 8-bit

; local variable

; passed to stack

; output registers: none - 8-bit

; local variable

; passed to stack

; 4-bits of leading

; zeros, 4-bits data

;

pshx ; store old values of X and A

psha

tsx ; transfer SP contents to X

ldaa 5,x ; load ASCII char from stack

adda #30 ; stubtract 30 from ASCII

cmpa #3a ; check if number was less than A (10)

blt Done ; if so, done, restore registers

adda #27 ; if not, convert to "a" thru "f" value

Done: staa 5,x ; put HEX number on stack

pula ; restore contents of A and X

pulx

rts

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Reslt:

; Input: 16 bit variable passed to stack

; Output: Puts 2 ASCII Char to Montr

; !!Data NOT removed from stack!!

; Does not corrupt registers

; Calls Subroutine Parse

pshy

pshx

psha

tsx

ldaa 7,x

psha

psha

jsr Parse

jsr HtoA

jsr PutC

jsr HtoA

jsr PutC

ldaa 8,x

psha

psha

jsr Parse

jsr HtoA

jsr PutC

jsr HtoA

jsr PutC

ldx #6d53

pshx

jsr PutC

jsr PutC

pula

pulx

puly

rts

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Parse:

; Subr to turn 8-bit Hex into

; 2 4-bit Hex

; INPUT: 2 pushes of one 8-bit Hex

; passed to the stack

; OUTPUT: 2 nibbles of 4-bit Hex

; passed to the stack,

; 4-bits of leading zeros

pshx

psha

pshb

tsx

ldaa 6,x

tab

anda #0f

lsrb

lsrb

lsrb

lsrb

staa 7,x

stab 6,x

pulb

pula

pulx

rts

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