In the ALTFP_SINCOS core, the sine of 210 degrees gives the wrong value.

Description

You may see this problem when implementing a sine function using the ALTFP_SINCOS Megacore in Quartus® II software versions 11.0 and 11.0SP1. 

Resolution

To workaround this, change the <altfp_sincos_variant_file_name>.vhd file, line 22850 as follows:

Change from:
wire_mantissanorm_add_datab <= ( "0000000000000000000000" & mantissanormnode_w(12));

Change to:
wire_mantissanorm_add_datab <= ( "0000000000000000000000" & mantissanormnode_w(11));