[fpc-pascal] subtract longwords with rollover
hartnegg at gmx.de
Thu Nov 28 17:37:39 CET 2013
How can I subtract two longwords such that when the result becomes
negative, it rolls over?
A := A - B triggers runtime error 201 when the result is negative.
dec (A,B) rolls over, but triggers runtime error 201 when A is higher
than the highest possible value of longint.
Is dec only declared for longint, but not for longword?
dec(longint(A),B) fails when the result is larger than 2 billion.
I cannot use longint instead of longword, this causes problems in other
parts of the code.
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