Use macpack for debugging, cosmetic changes

[cc65] / libsrc / common / isalnum.s

diff --git a/libsrc/common/isalnum.s b/libsrc/common/isalnum.s
index e8654ad9fbd0c26e4722d2de8360359ff4a28c32..8c29964edd673781214ccfe280b079b21360af1c 100644 (file)
--- 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
+