National-instruments AutoCode NI MATRIX Manual do Utilizador descarregar pdf (Página 188)

Chapter 6 Vectorized Code Generation

top[-1+i] = R_P[-1+i]*U->gain_1[-1+i];

}

/* ---------------------------- Procedure Super Block */

/* {vecproc.3} */

vecproc(&top[0], &Y->vecproc_3_1[0], &vecproc_3_i);

iinfo[0] = vecproc_3_i.iinfo[0];

if( iinfo[0] != 0 ) {

vecproc_3_i.iinfo[0] = 0; goto EXEC_ERROR;

}

A vectorized procedure interface suffers from a form of the copy-back

problem. When using the vectorized interface, each time the procedure is

called, the inputs and outputs must be an array. Therefore, if an array is not

connected as the input or output, AutoCode must generate code to copy

data into a temporary array and then pass that array. In other words, if the

inputs and/or outputs are not connected to naturally conform to a vector

interface, the copies required might add significant overhead to the

procedure call, eliminating the benefits of the vectorized interface.

Ada Array Aggregates and Slices

All of the examples presented include generated C code. AutoCode will

generate the equivalent Ada code, except that use of array aggregation and

slices are used when possible. Example 6-11 is the equivalent Ada code for

a diagram previously shown in Figure 6-2.

Note Only the relevant subsystem code is listed.

Example 6-11 Ada Generated Code (for Figure 6-2)

procedure subsys_1 is

------ Local Block Outputs. ------

Throttle : RT_FLOAT_AY(0..4);

------ Algorithmic Local Variables. ------

i_1 : RT_INTEGER;

j : RT_INTEGER;

k_1 : RT_INTEGER;

begin

-------- Initialization. --------

if SUBSYS_PREINIT(1) then

iinfo(0..3) := (0,1,1,1);

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National-instruments AutoCode NI MATRIX Manual do Utilizador Página 188