Hi all,
I'm using a Motorola 68HC11 microcontroller. My board is made by Axiom --
model #CME11E9-EVBU. I'm having a problem with a code of mine.
It's suppose to output a string of characters to the screen. My problem is
that whenever I push and pull data from the stack it will only display parts
of the string. However, if I take out the PSH and PUL mnemonics it works.
Why is that?
Thanks in advance!
Here's my code:
PUTCHAR EQU $E466 Built-in subroutine for printing char on screen
GETCHAR EQU $E459 Built-in subroutine for getting keystrokes
ORG $0100 Staring memory location
PSHA Storing the contents of ACCA into the stack
PSHY Storing the contents of REG Y into the stack
LDY #STRTXT Load the starting address of STRTXT into REG Y
JSR LOOPX Call subroutine LOOPX
LDY #TESTXT Load the starting address of TESTXT into REG Y
JSR LOOPX Call subroutine LOOPX
LOOPX LDAA 0,Y Load ACCA with data in REG Y's location
CMPA #$04 Compare ACCA with EOF char
BEQ DONE If equal branch to DONE
JSR PUTCHAR Call built-in subroutine PUTCHAR
INY Increment REG Y
BRA LOOPX Branch to LOOPX
DONE RTS End of subroutine
PULY Pull contents of REG Y from the stack
PULA Pull contents of ACCA from the stack
END
STRTXT FCC 'THISMCU ' Assign STRTXT with specified string
FCB $04 Add EOF character
TESTXT FCC 'TEST123 ' Assign STRTXT with specified string
FCB $04 Add EOF character
RMB 2 Reserve Memory Byte?
I'm using a Motorola 68HC11 microcontroller. My board is made by Axiom --
model #CME11E9-EVBU. I'm having a problem with a code of mine.
It's suppose to output a string of characters to the screen. My problem is
that whenever I push and pull data from the stack it will only display parts
of the string. However, if I take out the PSH and PUL mnemonics it works.
Why is that?
Thanks in advance!
Here's my code:
PUTCHAR EQU $E466 Built-in subroutine for printing char on screen
GETCHAR EQU $E459 Built-in subroutine for getting keystrokes
ORG $0100 Staring memory location
PSHA Storing the contents of ACCA into the stack
PSHY Storing the contents of REG Y into the stack
LDY #STRTXT Load the starting address of STRTXT into REG Y
JSR LOOPX Call subroutine LOOPX
LDY #TESTXT Load the starting address of TESTXT into REG Y
JSR LOOPX Call subroutine LOOPX
LOOPX LDAA 0,Y Load ACCA with data in REG Y's location
CMPA #$04 Compare ACCA with EOF char
BEQ DONE If equal branch to DONE
JSR PUTCHAR Call built-in subroutine PUTCHAR
INY Increment REG Y
BRA LOOPX Branch to LOOPX
DONE RTS End of subroutine
PULY Pull contents of REG Y from the stack
PULA Pull contents of ACCA from the stack
END
STRTXT FCC 'THISMCU ' Assign STRTXT with specified string
FCB $04 Add EOF character
TESTXT FCC 'TEST123 ' Assign STRTXT with specified string
FCB $04 Add EOF character
RMB 2 Reserve Memory Byte?
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