Scicos Block
fr - eng


Left shift circulate integer modulo function block

\epsfig{file=LCMODULO_f.eps,height=90pt}

Contents

Palette

Description

This block realizes a left shift circulate integer modulo function. The output is the left shift circulate N bit of the input word, define by a length of Nbit bits using the 2 complement arithmetic notation. Then, the values of the output are comprise between $ \left[-2^{Nbit-1};2^{Nbit-1}-1\right]$.
This function is described by a nonconstant amplitude. Following the number of shift, this nonlinearity takes different slope. Fig.1 shows an example for a given length (Nbit=5), for one shift and two shift.

\begin{figure}\centering \subfigure[]{\scalebox{0.4}{% \input{lcmodulo_fnl_fig1.... ...} \subfigure[]{\scalebox{0.4}{% \input{lcmodulo_fnl_fig2.pstex_t}}} \end{figure}
Figure 1: Nonlinear function lcmodulo for Nbit=5. (a) One shift; (b) Two shifts

This function is modelled with binary operators of C language. First block begins to convert input value, in an unsigned integer value. After it realizes N times the left shift. Table.1 shows necessary stages to realize this operation for an integer value defined by a length of 8 bits.

Table 1: Computation stages of the left binary shift circulate operation
Stages Operations Decimal Binary
1 Read unsigned integer value 150 1001 0110
2 Left shift binary 300 1 0010 1100
3 Tronquate to 8 bits 44 0010 1100
4 Addition of the tronquate bits 45 0010 1101

Computational function finally converts unsigned integer value in signed integer value and puts results in output register y.

Dialog box

\begin{figure}\begin{center} \epsfig{file=LCMODULO_f_gui.eps,width=270pt} \end{center}\end{figure}

Default properties

Interfacing function

Computational function

See also

Authors

A. Layec