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22 lines
436 B
ArmAsm
22 lines
436 B
ArmAsm
*
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* read one char from console
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*
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CRTS=$3ff01
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CRTD=$3ff03
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.globl _getchar
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.globl _putchar
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_getchar:
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move.b CRTS,R0
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and #1,R0 //receive register full
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beq _getchar //not yet
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move.b CRTD,R0 //read the char
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and.l #$7f,R0 //leave only 7 bits
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cmp.b #$0d,R0 //carriage return?
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bne l0
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move.b #$0a,R0 //turn into line feed
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l0:
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move R0,-(sp)
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jsr _putchar //echo it
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move (sp)+,R0 //pop arg
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rts
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