`zhbmv:`procedure`xHBMV`performs the matrix-vector multiply-add operation of the form`y := alpha*op( A )*x + beta*y`, where`op( X )`is one of`op( A ) = A`or`op( A ) = A'`.`ALPHA`and`BETA`are scalars, and`A`is an`N x N`Hermitian banded matrix, with`K`super-diagonals.`X`and`Y`are`N`element vectors.