X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;ds=sidebyside;f=libsrc%2Fcommon%2Ftoupper.s;h=adc3d4a337687baa8f70bd30e60392f414e76bf5;hb=4f6110604326357d378f373b917b92c7ad92997e;hp=43ff0812d5cb54bb7c01f8452052a9c1f067e7b9;hpb=53dd513176425872128ef26031d00952ef7a0628;p=cc65

diff --git a/libsrc/common/toupper.s b/libsrc/common/toupper.s
index 43ff0812d..adc3d4a33 100644
--- a/libsrc/common/toupper.s
+++ b/libsrc/common/toupper.s
@@ -5,18 +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
-	and	#$01		; Mask lower char bit
-	beq	L1		; Jump if not lower char
+	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
-	rts			; CC are set
-
-L1:	tya	     		; Get C back
-	rts			; CC are set
+       	adc    	#<('A'-'a')     ; make upper case char
+L9:	rts	  		; CC are set