This intrinsic inserts a UXTAB16 instruction into the instruction stream generated by the compiler. It enables you to extract two 8-bit values from one operand, zero-extend them to 16 bits each, and add the results to two 16-bit values from another operand.

unsigned int __uxtab16(unsigned int val1, unsigned int val2)

Where val2[7:0] and val2[23:16] hold the two 8-bit values to be zero-extended.

The __uxtab16 intrinsic returns the 8-bit values in val2, zero-extended to 16-bit values and added to val1.

Example:

unsigned int extend_add(unsigned int val1, unsigned int val2)
{
  unsigned int res;

    res = __uxtab16(val1,val2); /* res[15:0] = ZeroExt(val2[7:0] to 16 bits) 
                                     + val1[15:0]
                                   res[31:16] = ZeroExt(val2[31:16] to 16 bits)
                                     + val1[31:16]
                                 */
    return res;
}