Esempio n. 1
0
    virtual void visit(AstRepeat* nodep, AstNUser*) {
	// So later optimizations don't need to deal with them,
	//    REPEAT(count,body) -> loop=count,WHILE(loop>0) { body, loop-- }
	// Note var can be signed or unsigned based on original number.
	AstNode* countp = nodep->countp()->unlinkFrBackWithNext();
   	string name = string("__Vrepeat")+cvtToStr(m_repeatNum++);
	// Spec says value is integral, if negative is ignored
	AstVar* varp = new AstVar(nodep->fileline(), AstVarType::BLOCKTEMP, name,
				  nodep->findSigned32DType());
	varp->usedLoopIdx(true);
	m_modp->addStmtp(varp);
	AstNode* initsp = new AstAssign(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, true),
					countp);
	AstNode* decp = new AstAssign(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, true),
				      new AstSub(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, false),
						 new AstConst(nodep->fileline(), 1)));
	V3Number zero (nodep->fileline(), 32, 0);  zero.isSigned(true);
	AstNode* zerosp = new AstConst(nodep->fileline(), zero);
	AstNode* condp = new AstGtS(nodep->fileline(), new AstVarRef(nodep->fileline(), varp, false),
				    zerosp);
	AstNode* bodysp = nodep->bodysp(); if (bodysp) bodysp->unlinkFrBackWithNext();
	AstNode* newp = new AstWhile(nodep->fileline(),
				     condp,
				     bodysp,
				     decp);
	initsp = initsp->addNext(newp);
	newp = initsp;
	nodep->replaceWith(newp);
	nodep->deleteTree(); VL_DANGLING(nodep);
    }
Esempio n. 2
0
    AstNode* newSubNeg(AstNode* lhsp, vlsint32_t rhs) {
	// Return lhs-rhs, but if rhs is negative use an add, so we won't
	// have to deal with signed math and related 32bit sign extension problems
	if (rhs == 0) {
	    return lhsp;
	} else if (lhsp->castConst()) {
	    // Optional vs just making add/sub below, but saves constification some work
	    V3Number num (lhsp->fileline(), lhsp->width());
	    num.opSub(lhsp->castConst()->num(), V3Number(lhsp->fileline(), 32, rhs));
	    num.isSigned(lhsp->isSigned());
	    AstNode* newp = new AstConst(lhsp->fileline(), num);
	    return newp;
	} else if (rhs > 0) {
	    AstNode* newp = new AstSub(lhsp->fileline(), lhsp,
				       new AstConst(lhsp->fileline(), AstConst::Unsized32(), rhs));
	    // We must make sure sub gets sign of original value, not from the constant
	    newp->dtypeFrom(lhsp);
	    return newp;
	} else {  // rhs < 0;
	    AstNode* newp = new AstAdd(lhsp->fileline(), lhsp,
				       new AstConst(lhsp->fileline(), AstConst::Unsized32(), -rhs));
	    // We must make sure sub gets sign of original value, not from the constant
	    newp->dtypeFrom(lhsp);
	    return newp;
	}
    }