Applesoft: Internals--Error Processor Routines



ERROR           D412

Checks ERRFLG and jumps to HNDLERR if ONERR is active. Otherwise it prints

<cr> "?"  <error message pointed to by X> "ERROR".  If this is during program

execution then it also prints" IN " and the CURLIN.



HANDLERR        F2E9

Saves CURLIN in ERRLIN, TXTPTR in ERRPOS, X in ERRNUM, and REMSTK in ERRSTK.

X contains the error code.  See the Applesoft Reference Manual page 136 for

the value of X for a given error.



RESUME          F317

Restores CURLIN from ERRLIN and TXTPTR from ERRPOS and transfers ERRSTK into

the 6502 stack pointer.



ISCNTC          D858

Checks the Apple keyboard for a CTRL-C ($83).  Executes the BREAK routine

if there is a CTRL-C.



CHKNUM          DD6A

Make sure FAC is numeric.  See CHKVAL.



CHKSTR          DD6C

Make sure FAC is a string.  See CHKVAL.



CHKVAL          DD6D

Takes the result of the most recent FAC operation and check this result for a

string or numeric variable.  A TYPE MISMATCH ERROR results if FAC and C don't

agree.

On entry:

C set checks for strings

C clear checks for numerics.



ERRDIR          E306

Causes ILLEGAL DIRECT ERROR if the program isn't running.  X is modified.



ISLETC          E07D

Checks A for an ASCII letter ("A" to "Z").  On exit C set if A is a letter.



PARCHK          DEB2

Checks for "(", evaluates a formula, and checks for ")".  Uses CHKOPN and

FRMEVL then falls into CHKCLS.



CHKCLS          DEB8

Checks at TXTPTR for ")".  Uses SYNCHR.



CHKOPN          DEBB

Checks at TXTPTR for "(".  Uses SYNCHR.



CHKCOM          DEBE

Checks at TXTPTR for ",".  Uses SYNCHR.



SYNCHR          DECO

Checks at TXTPTR for the character in A.  TXTPTR is not modified.  Normally

exits through CHRGET.  Exits with SYNTAX ERROR if they don't match.





Apple Tech Notes





Keywords:  <None>



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This information is from the Apple Technical Information Library.



ArticleID: TECHINFO-0000082



19960724 15:55:27.00

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