LIST 1 7.TXT
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******************************************************************
* *
* 68000 ASSEMBLER COURSE ON ATARI ST *
* *
* by The Fierce Rabbit (from 44E) *
* *
* Listing number 1 / Course number 7 *
* *
******************************************************************
START MOVE.L #MENU,-(SP) pass address of sentence
MOVE.W #9,-(SP) function number
TRAP #1 Gemdos call
ADDQ.L #6,SP stack correction
* wait for key press
MOVE.W #7,-(SP) function number 7
TRAP #1 Gemdos call
ADDQ.L #2,SP stack correction
* test the result
CMP.W #"Q",D0 capital Q?
BEQ QUIT yes, bye bye
CMP.W #"q",D0 lowercase q?
BEQ QUIT yes, bye bye
CMP.W #"V",D0 capital V?
BEQ DISPLAY yes -> display the message
CMP.W #"v",D0 lowercase v?
BNE START no. So we have another letter
* as a response. It's not valid, so we start again from the beginning
DISPLAY MOVE.L #MESSAGE,-(SP) address of 'hello'
MOVE.W #9,-(SP) function number
TRAP #1 Gemdos call
ADDQ.L #6,SP stack correction
* We wait for a key press to contemplate
MOVE.W #7,-(SP)
TRAP #1
ADDQ.L #2,SP
BRA START return to the beginning
QUIT MOVE.W #0,-(SP)
TRAP #1
SECTION DATA
MENU DC.B 27,"E",27,"p"
DC.B "QUIT (Q) OR SEE THE MESSAGE (V)?"
DC.B 27,"q",13,10,0
EVEN
MESSAGE DC.B "HELLO",0
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