The standard specifies that the size of a vecval should be calculated as
(size - 1)/32 + 1. When size is a PLI_INT32 this is needed to prevent an
overflow, but when the size is unsigned this can be simplified to
(size + 31)/32 since the size must fit into an integer, but we have an
extra significant bit in an unsigned so no overflow can happen.
This patch changes the code to use the correct version of the equation
depending on the context.
The previous patch does this in vvp/vpi_priv.cc