Atari XL - Page 211

Advanced Techniques
199
32110 DATA LINE NO TOO LARGE, INPUT
TYPE ERROR,DIMENSIONING
ERROR,STACK
OVERFLOW,
OVER/UNDER FLOW
32120 DATALINE NOT FOUND,NEXT
WITHOUT FOR,LINE TOO LONG,
GOSUB/FOR DELETED,RETURN
WITHOUT GOSUB
32130 DATA GARBAGE, INVALID STRING,
LOAD PROG TOO LONG, DEVICE
NUMBER, LOAD FILE ERROR
32500 LINE=PEEK(186)+PEEK(187)*256
32510 CODE=PEEK(195)
32520 PRINT" {BELL}ERROR "iCODE;" IN
LINE
"iLINE
32530 P=(CODE-2)*20+1
32540 PRINT ERROR$(P,P+19)
32550 END
If you save this program on tape using the LIST
command it can be reloaded to form a temporary
part of the program you are developing without
disturbance.
MACHINE CODE SUBROUTINES
The XL's microprocessor does not understand
BASIC programs without some assistance; it
understands a much cruder set of instructions
called machine code or machine language. BASIC
programs can be run only because the XL has some
machine code programs permanently stored in .
read-only memory (ROM) which interpret the
BASIC. Writing programs in machine code is more
difficult than using BASIC, but can be very
worthwhile as machine code programs run very
much faster. Machine code is beyond the scope of
this book, but there are several books available