;
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;
|
; rom02.s -- terminal output, polled
|
; rom02.s -- terminal output, polled
|
;
|
;
|
|
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.set tba,0xF0300000 ; terminal base address
|
.set tba,0xF0300000 ; terminal base address
|
|
|
add $8,$0,tba ; set terminal base address
|
add $8,$0,tba ; set terminal base address
|
L1:
|
L1:
|
add $10,$0,'a' ; set char to ASCII 'a'
|
add $10,$0,'a' ; set char to ASCII 'a'
|
L2:
|
L2:
|
ldw $9,$8,8 ; load transmitter status word into $9
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ldw $9,$8,8 ; load transmitter status word into $9
|
and $9,$9,1 ; extract LSB - 'transmitter ready'
|
and $9,$9,1 ; extract LSB - 'transmitter ready'
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beq $9,$0,L2 ; loop while not ready
|
beq $9,$0,L2 ; loop while not ready
|
stw $10,$8,12 ; load char into transmitter data register
|
stw $10,$8,12 ; load char into transmitter data register
|
add $10,$10,1 ; next char
|
add $10,$10,1 ; next char
|
sub $9,$10,'z'+1 ; check if above 'z'
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sub $9,$10,'z'+1 ; check if above 'z'
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bne $9,$0,L2 ; no - loop
|
bne $9,$0,L2 ; no - loop
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j L1 ; else reset to 'a'
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j L1 ; else reset to 'a'
|
|
|
