Compaq 21264 - Manual (Page 322)

D–24 PALcode Restrictions and Guidelines Alpha 21264/EV67 Hardware Reference Manual
Restriction 48: MB Bracketing of Dcache Writes to Force Bad Data ECC and Force
D.44 Restriction 48: MB Bracketing of Dcache Writes to Force Bad
Data ECC and Force Bad Tag Parity
Writes to DC_CTL[F_BAD_DECC] and DC_CTL[DCDAT_ERR_EN] must be brack-
eted by MB instructions to quiesce the memory system. The Istream must also be qui-
esced before and during the sequence, as described in Section D.26.