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22 lines
508 B
ArmAsm
22 lines
508 B
ArmAsm
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; Ullrich von Bassewitz, 02.06.1998
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; int toupper (int c);
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;
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.export _toupper
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.import __ctype, __cdiff
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_toupper:
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cpx #$00 ; Outside valid range?
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bne L9 ; If so, return the argument unchanged
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tay ; Get c into Y
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lda __ctype,y ; Get character classification
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lsr a ; Get bit 0 (lower char) into carry
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tya ; Get C back into A
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bcc L9 ; Jump if not lower char
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clc
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adc __cdiff ; make upper case char
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L9: rts ; CC are set
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