This intrinsic inserts a USAX instruction into the instruction stream generated by the compiler. It enables you to exchange the halfwords of the second operand, subtract the high halfwords and add the low halfwords.

The GE bits in the APSR are set according to the results.

unsigned int __usax(unsigned int val1, unsigned int val2)

where:

The __usax intrinsic returns:

Each bit in APSR.GE is set or cleared for each byte in the return value, depending on the results of the operation. If res is the return value, then:

Example:

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

    res = __usax(val1,val2); /* res[15:0] = val1[15:0] + val2[31:16]
                                res[31:16] = val1[31:16] - val2[15:0]
                              */
    return res;
}