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getinput - Specified input argument object from `function` object

Syntax

inputobj = getinput(ff,input_name)

Description

inputobj = getinput(ff,input_name) returns the input object that accesses input_name. Enter input_name in single quotation marks because it is a string.

Note After you execute a function, the information returned by getinput may not be the same as the information returned before you run the method.

This occurs because the compiler uses stack and register locations as temporary storage and may overwrite the contents of either the stack or registers during execution. In particular, when your function stores the function return value in one of the input variables, the compiler overwrites the value of the input with the output value. Refer to "Examples" to see this in use.

Examples

Use getinput to see the properties of an input object in a function object:

sin_t=createobj(cc,'sin_taylor')

FUNCTION Object
  Function name     : sin_taylor
  File found        : hiltut.c
  Start address     : [12328 0]
  All variables     : a1, a2, a3, acc, x, xpow
  Input variables   : x
  Return type       : short

sin_t.inputvars

ans = 

    x: [1x1 ccs.rnumeric]

x_inobj=getinput(sin_t,'x')

NUMERIC Object stored in register(s): 
  Symbol name              : x
  Register                 : A4
  Datatype                 : Unknown
  Wordsize                 : 16 bits
  Register units per value : 1 ru
  Representation           : signed
  Bit padding (post)       : 16
  Size                     : [ 1 ]
  Total register units     : 1 ru
  Array ordering           : row-major

x_inobj

NUMERIC Object stored in register(s): 
  Symbol name              : x
  Register                 : A4
  Datatype                 : Unknown
  Wordsize                 : 16 bits
  Register units per value : 1 ru
  Representation           : signed
  Bit padding (post)       : 16
  Size                     : [ 1 ]
  Total register units     : 1 ru
  Array ordering           : row-major

Demonstrate that the information from getinput may change after executing a function.

In your CCS project:

 void fl2q15(double *x, short *r,int nx); % r is where the output 
                                          % is stored

In the MATLAB^® command window, here is the code that demonstrates getinput changing.

% Create function class

cc = ccdsp;
ff = createobj(cc,'fl2q15')

% Create objects that will be used as inputs to fl2q15

input_x = createobj(cc,'input_x')  % Global variable--an array of 
                                   % doubles
write(input_x,[0.1 2.5 8.0]) % Write data into input_x

input_r = createobj(cc,'input_r')  % Global variable--an array of 
                                   % shorts

% Get input objects and assign values

xobj = getinput(ff,'x')
write(xobj,input_x.address)

robj = getinput(ff,'r')
write(robj,input_r.address) % Also means 'set the result to point 
                            % to the location of input_r'

nxobj = getinput(ff,'nx')
write(nxobj,3)

% Run the function

run(ff)

% Read the result

output_err = read( deref( robj ) )  % Returns the wrong result 
                                    % because robj now holds a 
                                    % different value

output_correct = read( input_r ) )

Gives the correct result because the address of input_r did not change.

getinput - Specified input argument object from function object

Syntax

Description

Examples

See Also

getinput - Specified input argument object from `function` object