--- layout: fc_discuss_archives title: Message 50 from Frama-C-discuss on July 2012 ---
Dear all, We stumbled upon the following issue today: We have a little toy program (see code below) that uses the modulo operator in an assertion. By looking at the state dumps generated by Frama_C_dump_each(), value analysis should be able to assign the value "valid" to our assertion. Instead, the value unknown is assigned. The question is: To what extent can Value Analysis reason about the modulo operator? What should one be aware of when using it in ACSL annotations? Thank you very much in advance, Sergio A. Feo-Arenis The program: ------------------------------------------------------------------------------ #include "builtin.h" int x; void f(int b, int a) { if (b) x = 2*a; else x = 2*a+1; } int main() { int y; int b = 0; y = Frama_C_interval(0,100); if (y == 27) b = 1; else b = 0; f(b, y); Frama_C_dump_each(); //@ assert (y == 27) ==> ((x % 2 == 0)); return 0; } ------------------------------------------------------------------------------ We called frama-c with the following parameters: frama-c-gui test.c /usr/share/frama-c/builtin.c -val -slevel 10 -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.gforge.inria.fr/pipermail/frama-c-discuss/attachments/20120726/7a712fcf/attachment.html>