?OV ERROR
Dragon Data Dragon 32/64
Severity: MinorWhat it means
?OV ERROR means a calculation produced a number too large for BASIC to handle.
Dragon BASIC can handle numbers up to approximately 1.7 x 10^38.
Break large calculations into smaller steps or use logarithms.
Affected Models
- Dragon 32
- Dragon 64
- Dragon 200E
- XRoar emulator
Common Causes
- Multiplication producing a result larger than 1.7E+38
- Exponentiation with large values
- Loop that keeps multiplying without bounds
- Division by a very small number
How to Fix It
-
Identify which calculation is causing the overflow.
Add PRINT statements before the failing line to see the values.
Find which variable is growing beyond the limit. -
Break the calculation into smaller steps.
Instead of A = B * C * D, compute X = B * C first, then A = X * D.
This can sometimes avoid intermediate overflow. -
Check loop bounds to prevent runaway growth.
If a loop multiplies a variable repeatedly, it can overflow quickly.
Add a check: IF A > 1E30 THEN PRINT "TOO LARGE" : STOP
Frequently Asked Questions
Is the numeric range the same as the TRS-80 CoCo?
Yes.
Both use the same Microsoft Extended Color BASIC with identical floating-point routines.
The maximum value is approximately 1.7 x 10^38 on both machines.
What happens with very small numbers (underflow)?
Numbers smaller than approximately 2.94 x 10^-39 are silently rounded to zero.
Unlike overflow, underflow does not produce an error.