User guide

68 www.xilinx.com System Generator for DSP User Guide
UG640 (v 12.2) July 23, 2010
Chapter 1: Hardware Design Using System Generator
In order to verify that the functionality of two blocks are equal, we also use another MCode
block to compare the outputs of two blocks. If the two outputs are not equal at any given
time, the error checking block will report the error. The following function does the error
checking:
function eq = error_ne(a, b, report, mod)
persistent cnt, cnt = xl_state(0, {xlUnsigned, 16, 0});
switch mod
case 1
eq = a==b;
case 2
eq = isnan(a) || isnan(b) || a == b;
case 3
eq = ~isnan(a) && ~isnan(b) && a == b;
otherwise
eq = false;
error(['wrong value of mode ', num2str(mod)]);
end
if report
if ~eq
error(['two inputs are not equal at time ', num2str(cnt)]);
end
end
cnt = cnt + 1;
The block is configured as following: