; isascii.s ; ; This file is part of ; cc65 - a freeware C compiler for 6502 based systems ; ; https://cc65.github.io ; ; See "LICENSE" file for legal information. ; ; int isascii (int c); ; .export _isascii .import return0 _isascii: asl a ; high-bit to carry txa ; check range of input param bne @L1 ; out-of bounds? adc #$FF ; calculate return value based on carry rts @L1: jmp return0 ; return false