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# [Frama-c-discuss] Frama-C labels/States

*Subject*: [Frama-c-discuss] Frama-C labels/States*From*: barbaraisabelvieira at gmail.com (Bárbara Vieira)*Date*: Fri Nov 21 17:43:10 2008

Hi everyone! I?m using Frama-C new version. I was writing a predicate to a very simple function, and I don?t understand why it doesn?t distinguish the states when the proof obligations are generated. That is, when I apply the axiom, I should have all the variables in two different states to prove the proof obligation generated by the assert clause, and I have the variables in the same state. The code is the following: ******************************************************************** /*@ axiomatic InterInv1 { @ predicate interInv{L1,L2} @ (int i, unsigned char *indata_i, unsigned char *outdata_i,unsigned char x_i, @ unsigned char y_i, unsigned char *d_i, unsigned char tx_i, unsigned char ty_i, @ unsigned char *dkey_i, @ unsigned char *indata_f, unsigned char *outdata_f,unsigned char x_f, @ unsigned char y_f, unsigned char *d_f, unsigned char tx_f, unsigned char ty_f, @ unsigned char *dkey_f,int j, unsigned long len); } @ axiomatic InterInv2 { @ axiom interInv_ind{L1,L2}: @ \forall int i, unsigned char *indata_i, unsigned char *outdata_i, unsigned char x_i, @ unsigned char y_i, unsigned char *d_i,unsigned char tx_i, unsigned char ty_i,unsigned char *dkey_i, @ unsigned char *indata_f, unsigned char *outdata_f, @ unsigned char x_f, unsigned char y_f, unsigned char *d_f, @ unsigned char tx_f, unsigned char ty_f,unsigned char *dkey_f, @ int j, unsigned long len; @ (\at(x_f,L2) == ((\at(x_i,L1)+1)&0xff) && @ \at(tx_f,L2)== \at(d_i[x_f],L1) && @ \at(y_f,L2) == ((\at(tx_f,L2)+ \at(y_i,L1))&0xff) && @ \at(ty_f,L2)== \at(d_i[y_f],L1) && @ \at(d_f[x_f],L2)== \at(ty_f,L2) && @ \at(d_f[y_f],L2) == \at(tx_f,L2) && @ \at(dkey_f[((len>>3L)-j)*i],L2) == \at(d_f[(tx_f+ty_f)&0xff],L2) && @ \at(outdata_f[i],L2) == (\at(d_f[(tx_f+ty_f)&0xff],L2) ^ \at(indata_f[i],L2)) && @ \at(indata_f[i],L2) == \at(indata_i[i],L2)) ==> @ interInv{L1,L2}(i,indata_i,outdata_i,x_i,y_i,d_i,tx_i,ty_i,dkey_i, @ indata_f,outdata_f,x_f,y_f,d_f,tx_f,ty_f,dkey_f,j,len); @ } @*/ /*@ requires \valid_range(indata,0,len) && @ \valid_range(outdata,0,len) && @ 0<=i<=len && @ \valid_range(d,0,255) && @ \valid_range(dkey,0,len); @ ensures @ interInv{Old,Here}(i,indata,outdata,x,y,d,tx,ty,dkey,indata,outdata,x,y,d,tx ,ty,dkey,j,len); @*/ void LOOP(int i, unsigned char x, unsigned char y,unsigned char tx, unsigned char ty, unsigned char *d, unsigned char *outdata, unsigned char *indata, unsigned char *dkey, int j, const unsigned long len) { x=((x+1)&0xff); tx=d[x]; y=((tx+y)&0xff); ty=d[y]; d[x]= ty; d[y]=tx; dkey[((len>>3L)-j)*i] = d[(tx+ty)&0xff]; (outdata[i]) = (d[(tx+ty)&0xff] ^ (indata[i])); /*@ ghost goto L; */ /*@ ghost L:*/ /*@ assert @ interInv{Pre,L}(i,indata,outdata,x,y,d,tx,ty,dkey,indata,outdata,x,y,d,tx,ty ,dkey,j,len); @*/ } ******************************************************************** I made a post some days ago asking if I can specify the axioms for predicates in the way I did in the example above. Does anybody knows the answer? It is equivalent to the definition of an ?axiomatic? with the predicates and axioms, or the generated proof obligations, aren?t the same? Thanks. Best regards, B?rbara -------------- next part -------------- An HTML attachment was scrubbed... URL: http://lists.gforge.inria.fr/pipermail/frama-c-discuss/attachments/20081121/a5a050f7/attachment.html

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