X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=libsrc%2Fcommon%2Fisalnum.s;h=8c29964edd673781214ccfe280b079b21360af1c;hb=bb4f3c447547c496dc3861e0a114ef8abc9d64b5;hp=e8654ad9fbd0c26e4722d2de8360359ff4a28c32;hpb=53dd513176425872128ef26031d00952ef7a0628;p=cc65

diff --git a/libsrc/common/isalnum.s b/libsrc/common/isalnum.s
index e8654ad9f..8c29964ed 100644
--- a/libsrc/common/isalnum.s
+++ b/libsrc/common/isalnum.s
@@ -8,8 +8,14 @@
 	.import		__ctype
 
 _isalnum:
+	cpx	#$00		; Char range ok?
+	bne	@L1		; Jump if no
 	tay
 	lda	__ctype,y	; Get character classification
 	and    	#$07		; Mask character/digit bits
 	rts
 
+@L1:	lda	#$00		; Return false
+	tax
+	rts
+