| C9E7
to CA23 |
BASIC error handler. This is a BASIC
statement executed whenever a BRK command is executed,
normally meaning an error of some type. It says:
| @=1;P.$6$7'"ERROR
"?0; |
| @=8;IF ?1 |
\ |
?2 P.LINE"! 1
& #FFFF;P.';E. |
It uses ?0 as the error number and ! 1 & #FFFF as the line
number. If the line number is zero then this is inferred
as a direct mode error, and no line number is displayed.
Usable by pointing 5,Y at C9E7, then jump C55B.
|
| CACD
to CB56 |
Execute NEXT.
CAD0 checks the value of the FOR/NEXT stack pointer (?15)
and causes BRK if 0, since this must mean no FOR/NEXT has
been set.
CAE5 - adds the STEP size to the variable.
CB16 - checks if the control variable has reached the
final value.
CB45 - moves the text pointer back to the statement after
the corresponding FOR statement. |
| CB57
to CB80 |
Execute FOR.
CB5F sets the control variable equal to its first value.
CB65 - checks that the FOR/NEXT stack pointer has not
exceeded the allowable range.
CB86 - saves a default STEP value of 1. |
| CB81
to CBA1 |
Execute TO.
CB89 saves the terminal value of the FOR control
variable. |
| CBA2
to CBD1 |
Execute STEP.
CBAA saves the STEP size.
CBC3 - saves the FOR/NEXT stack pointer at 15. |
| CBD2
to CBEB |
Execute GOSUB.
CBD8 tests the GOSUB stack pointer (14), and yields an
error if too many.
CBDE saves the return address, and increments the GOSUB
stack pointer. |
| CBEC
to CBC04 |
Executes RETURN.
CBEF tests the GOSUB stack pointer (14), and if 0 gives
the RETURN WITHOUT GOSUB ERROR.
CBF5 - pulls the return address from the data stack into
the text pointer at 5. |
