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.INDEX
;**********************************************************
; Check if the command entered is command A, command B,
; or invalid command.
;**********************************************************
CLP
Process_Cmd:
CMP
BEQ
CMP
BEQ
BRA
;**********************************************************
; Command A is entered.
; message A.
X = location of the message.
; routine which writes the message.
;**********************************************************
Cmd_A:
LDA
LDX
BRA
;**********************************************************
; Command B is entered.
;**********************************************************
Cmd_B:
LDA
LDX
BRA
;**********************************************************
; An invalid command is entered.
;**********************************************************
Cmd_I:
LDA
LDX
;**********************************************************
; Message is written to the destination.
; the destination area.
;**********************************************************
Output:
LDY
MVN
;**********************************************************
; Go back and scan for next command.
;**********************************************************
BRA
.END
16
X
A,#41H
Cmd_A
A,#42H
Cmd_B
Cmd_I
A = the number of bytes in
A,#11H
#Msg_A
Output
A,#11H
#Msg_B
Output
A,#0FH
#Msg_I
Y = location of
#Msg_Dest
0,0
Clear_Input
Figure 2-2. Sample Program Listing (Cont'd)
Reading Input
The instruction at the Clear_Input label clears any random data or
previous commands from the Cmd_Input byte. The Scan loop
continually reads the Cmd_Input byte to see if a command is entered
(a value other than 0 hex).
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Getting Started 2-5
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