Why am I getting incorrect results out of my DSP48e when I use the SIMD capability?
The SIMD (single input, multiple data) option allows the user to partition the DSP48E's internal ALU. In some cases, System Generator for DSP with an SIMD-enabled DSP48E block will produce incorrect results.
This is a problem with the System Generator for DSP simulation model and how the DSP48E block simulates the SIMD feature. Although this functions improperly in the Simulink environment, the implemented DSP48E will operate as expected.
To work around this issue, select the CARRYOUT port for the DSP48E. It does not have to be used or assigned, but must be present on the block's mask. This will not use any additional resources in hardware.
This known issue will be resolved in a future release of System Generator for DSP.