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As originally specified, both MTPR and MFPR set N,Z based on the transmitted/received longword data, cleared V, and left C untouched. The simulator hardwired this (except for the standardized TBCHK register) based on the CVAX microcode. In the 8200, accessing the RXCD register sets V for character sent/received. (The VAX vector MxPRs also return non-standard values for the condition codes.) This is one of the reasons that, in 1986, the VAX architecture spec was changed to make the condition codes UNPREDICTABLE following MTPR or MFPR. Accordingly, I've added a "hook" to support the 8200 and other non-standard MxPRs: global variable mxpr_cc_vc. At the start of MTPR or MFPR (only), this variable is set to 000<current C bit>. MTPR will set N and Z based on the transmitted operand and clear V and C. MFPR will set N and Z based on the received data and clear V and C. Then, at the end, mxpr_cc_vc, masked down to V & C, is ORed into the condition codes. Thus, if an IPR write or read does nothing special, MTPR and MFPR will get the canonical results. N,Z set, V cleared, C preserved. However, an IPR routine can now specify a non-standard value for V and/or C by modifying mxpr_cc_vc. This tweak required changes only in vax_cpu.c. None of the model- specific IPR routines need to be changed, except for Matt's 8200 RXCD code. Anyone attempting implementation of further models (or VAX vectors) should be aware of this new capability.