Texas Instruments MSP50C6xx User Manual

Page 319

C– – Compiler

5-23

Code Development Tools

the MSP50C6xx length of the string. It is included in the

cmm_macr.h

file, and

is called STR_LENGTH(lstr). For example, STR_LENGTH(8) is 8–2 = 6.

Also note that the user has to supply the length of the input string and the length
of the output string in the string multiply operations: the result of multiplying a
string by an integer can be one word longer than the input string. Unpredictable
results may occur if parameter lgr is not at least equal to lgr+1.

5.5.10 Constant Functions

The only two constant functions implemented in C– – are

xfer_const

and

xfer_single

cmm_func xfer_const(int *out,int *constant_in,int lg)

It transfers

+2 integers from program ROM starting at address

constant_in

to RAM, starting at address

out

. Note that

constant_in

not doubled, because it is used in A0 in a MOV A0,*A0 operation. The C– –
compiler takes care of this.

cmm_func xfer_single(int *out,int *constant_in)

transfers a single value.

An example of the use of

xfer_const

is:

int array[8],i;

const int atan[80*8] ={.........640 integers );

/* .... */

for(i=0;i<80;i++){

xfer_const(array,&atan[i*8],STR_LENGTH(8));

/* ... now use array normally

..... */

}