XL Fortran for AIX 8.1

Language Reference



The CACHE_ZERO directive invokes the machine instruction, data cache block set to zero (dcbz). This instruction sets the data cache block corresponding to the variables you specified to zero. Use this directive with discretion.



is a variable associated with the cache block that is set to zero. The variable cannot be a procedure name, subroutine name, module name, function name, constant, label, zero-sized string, or an array with vector subscripts.


In the following example, assume that array ARRA has already been loaded into a cache block of 64 bytes. The data in the cache block is then set to zero.

   real(4) :: arrA(2**5)
 ! ....
 !IBM* CACHE_ZERO(arrA(1))             ! set data in cache block to zero

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