X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=libsrc%2Fcommon%2Ftoupper.s;h=adc3d4a337687baa8f70bd30e60392f414e76bf5;hb=96b5da41f15db5d9d8a550eb98c47a416753ad15;hp=ab7711cb214ed252803342d814c741c972243296;hpb=dccc89edaebdf39d8a3f16a96f2816dee472a5fb;p=cc65

diff --git a/libsrc/common/toupper.s b/libsrc/common/toupper.s
index ab7711cb2..adc3d4a33 100644
--- a/libsrc/common/toupper.s
+++ b/libsrc/common/toupper.s
@@ -5,15 +5,17 @@
 ;
 
 	.export		_toupper
-	.import		__ctype, __cdiff
+	.import		__ctype
 
 _toupper:
+        cpx     #$00            ; Outside valid range?
+        bne     L9              ; If so, return the argument unchanged
 	tay			; Get c into Y
 	lda	__ctype,y	; Get character classification
 	lsr	a		; Get bit 0 (lower char) into carry
 	tya			; Get C back into A
        	bcc    	L9		; Jump if not lower char
        	clc
-	adc	__cdiff		; make upper case char
+       	adc    	#<('A'-'a')     ; make upper case char
 L9:	rts	  		; CC are set