openpower/sv/cr_int_predication.mdwn

   1 # New instructions for CR/INT predication
   2
   3 See:
   4
   5 * <https://bugs.libre-soc.org/show_bug.cgi?id=533>
   6
   7 Basic concept:
   8
   9 * CR-based instructions that perform simple AND/OR/XOR from all four bits
  10   of a CR to create a single bit value (0/1) in an integer register
  11 * Inverse of the same, taking a single bit value (0/1) from an integer
  12   register to selectively target all four bits of a given CR
  13 * Vectorisation of the same
  14
  15 Purpose:
  16
  17 * To provide a merged version of what is currently a multi-sequence of
  18   CR operations (crand, cror, crxor) with mfcr and mtcrf
  19 * To provide a vectorised version of the same, suitable for advanced
  20   predication