Specifications

System Macros Invoked by Drivers

CPUDISP

The destination parameter contains the address to which the code generated

by the invocation of the CPUDISP macro passes control to continue with CPU-

speciﬁc processing.

[environ=VMS]

Identiﬁcation of the run-time environment of the code generated by the CPUDISP

macro. There is no need to change the default value of this argument.

continue=NO

Speciﬁes whether execution should continue at the line immediately after the

CPUDISP macro if the value at EXE$GB_CPUTYPE does not correspond to

any of the values speciﬁed as the CPU-type in the addrlist argument. A fatal

bugcheck of UNSUPRTCPU occurs if the dispatching code does not ﬁnd the

executing processor identiﬁed in the addrlist and the value of continue is NO.

Description

The CPUDISP macro provides a means for transferring control to a speciﬁed

destination depending on the CPU type of the executing processor. For those

processors that do not have a unique CPU type, CPUDISP also provides the

means to dispatch on a particular CPU subtype.

To accomplish this, CPUDISP builds one or two case tables. The ﬁrst CASEB

instruction uses words in the ﬁrst case table to set up a transfer based on each

CPU-type speciﬁed in the addrlist argument. CPUDISP constructs the second

case table in the event it encounters a CPU subtype in the addrlist.

CPUDISP constructs appropriate symbolic constants for each CPU-type listed in

addrlist, and compares them against the contents of EXE$GB_CPUTYPE. These

constants have the form PR$_SID_TYPCPU-type.

For each CPU subtype it encounters in the addrlist argument, CPUDISP also

constructs symbolic constants of the form PR$_XSID_xx_yyy, where xx is the

generic CPU type (for example CV) and yyy is the CPU subtype (420, 520, 650,

9CC, or 60 for CV). It compares the value of PR$_XSID_xx_yyy against the

contents of EXE$GB_CPUDATA+15.

2–11