Motorola MVME5100 Manual De Usuario

B-14

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MVME5100 VPD Reference Information

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * 

*

* cssect - checksum section

* description:

*      This component's purpose is to checksum the buffer pointed to

*      by the buffer pointer.

* notes:

* call:

*      argument #1 = buffer (section) to checksum

*      argument #2 = number of bytes in buffer

* return:

*

0xXX = checksum

*/

UCHAR

cssect(nvram_ptr, count)

register UCHAR *nvram_ptr; /* NVRAM buffer pointer */

register UINT count; /* count, number of bytes */

{

register UCHAR y, isum, sum;

for (sum = 0; count; count--) {

y = *nvram_ptr++;

isum = sum + y;

if ((isum < y) || (isum < sum)) isum += 1;

sum = isum;

}

return (sum);  /* return calculated checksum */

}