Chapter 6 Vectorized Code Generation© National Instruments Corporation 6-5 AutoCode Referenceaddition to issues with the standard block library, all general BlockScriptBlocks within the diagram are implemented as 1-based arrays. If thesubscript can be evaluated at generation-time, the 0-based subscript will beused.Note The extra computation of the subscripts represents a compatibility issue.Elimination of the 1-based array representation in BlockScript will be addressed in a futurerelease.Signal ConnectivityOne of the greatest modeling capabilities provided in the SystemBuildmodel is the ability to connect any output signal to many input pins. Thatrequirement, coupled with increased traceability, necessitated the use ofscalars in the generated code. Vectorized code generation requires a moredisciplined design if vectorization is to improve the generated code.Although it is not necessary to redesign your model, you should be awarethat the flexibility of the SystemBuild Editor lets you design models thatvectorize poorly, which means they require the code to be unrolled. In otherwords, generating arrays is not enough for vectorized code; theconnectivity of the model is vital in enabling loops in the generated code.Block OutputsThe outputs of a block always can be generated as one or more arrays. Theoutputs of one block cannot be part of the same array used for outputs ofanother block. The creation of the arrays are controlled by the vectorizationmode and labels of the individual output pins.Block InputsThe inputs of a block are either SuperBlock (subsystem) external inputsand/or outputs from other basic blocks. Those inputs might or might not bean array and/or might not be connected in a way that allows for the code tobe rolled into a loop. The diagram in Figure 6-1 represents poor inputconnectivity that prevents a rolled loop. Refer to Example 6-3.
