Apparatus and method for propagating conditionally evaluated values in simd/vector execution using an input mask register

Abstract

An apparatus and method for propagating conditionally evaluated values are disclosed. For example, a method according to one embodiment comprises: reading each value contained in an input mask register, each value being a true value or a false value and having a bit position associated therewith; for each true value read from the input mask register, generating a first result containing the bit position of the true value; for each false value read from the input mask register following the first true value, adding the vector length of the input mask register to a bit position of the last true value read from the input mask register to generate a second result; and storing each of the first results and second results in bit positions of an output register corresponding to the bit positions read from the input mask register.

We claim: 
     
         1 . A method for propagating conditionally evaluated values comprising the operations of:
 reading each value contained in an input mask register, each value being a true value or a false value and having a bit position associated therewith;   storing in an output vector register a first value related to the size of the vector register for all values in the input mask register corresponding to a true value until the first false value is encountered;   storing in the output vector register for the first false value and each subsequent false value, a second value equal to the bit positions of the false values; and   once the first false value is encountered, storing in the vector output register for each true value the second value associated with the last encountered false value.