Aah, thank you. That clears things up. Hooray for documentation! It's the same as suspected and listed below.
(and I noticed a mistake. I meant to say only if the numerator (left-hand side operand) is negative, not positive) Gareth aka. Kit On Fri 01/06/18 12:42 , "Christo Crause" christo.cra...@gmail.com sent: > On Fri, Jun 1, 2018 at 11:13 AM, J. Gareth Moreton wrote: > Hi everyone, > > I'm starting to make some modifications to the optimizer so it optimises > div and mod operations on signed integers (I've done unsigned integers > already). One question that I've stumbled across... what are the rules > regarding the sign of the result? Experimenting with IDIV suggests it > returns a negative modulus only if the numerator is positive (so -28 / 3 = > -9 remainder -1, and -28 / -3 = 9 remainder -1, but 28 / -3 = -9 remainder > +1), which follows the Euclidean division rule of n = dq + r, where n is > the numerator, d is the divisor, q is the resultant quotient and r is the > resultant remainder. > > While I'm planning on being consistent with IDIV, what are the rules of > signed division in Free Pascal? There are hints that some dialects of > Pascal only return a positive modulus no matter what. > > Gareth aka. Kit > > " The sign of the result of a Mod operator is the same as the sign > of the left side operand of the Mod operator " > - https://freepascal.org/docs- html/current/ref/refsu45.html [1] > > Links: > ------ > [1] https://freepascal.org/docs- html/current/ref/refsu45.html > > _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-devel
