The Zmab extension allows to use C = A x B mode for matrix multiplication, where the setting of mcsr.mmode = 00 is legal.
The Zmabt extension allows to use C = A x BT mode for matrix multiplication, where the setting of mcsr.mmode = 01 is legal.
The Zmatb extension allows to use C = AT x B mode for matrix multiplication, where the setting of mcsr.mmode = 10 is legal.