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OPERATION AND APPLICATION
The third macro type is "send Primitive" which is functionally equivalent to
using the SEND NETWORK DATA command, but is far more flexible. This
macro begins with the same bytes as the two other types with the addition of a
macro options byte, a minimum reissue delay time word, and the Primitive
data. The macro options byte uses its five most significant bits to enable or
disable the following options.
D
The auto enable option which specifies whether to automatically enable
the macro for execution after definition is complete or not. If you do not
choose this option, you can explicitly enable the macro with the
ENABLE/DISABLE MACRO EXECUTION command.
D
The repetitive/non-repetitive option which defines how the macro will
be executed.
D
The freeze option which selects whether to freeze the macro and
response when an exception occurs.
D
The set first exception option which selects whether to set the exception
flag on the first response.
Unlike the two other macro types, the "send Primitive" macro type is not
implicitly enabled for execution. You must set Bit 0 to a value of 1 or use the
ENABLE/DISABLE MACRO EXECUTION command before the macro will be
scheduled for execution. The last option, Bit 4, causes the HIU to not check the
first macro response received for an exception. When the macro response buffer
is first allocated, its contents are undefined which will cause the first response
received to set the exception flag. Setting Bit 4 will prevent this exception, or
you can initialize the contents of the macro response buffer with the
INITIALIZE MACRO RESPONSE BUFFER command. Example 2–3 shows
examples of the bit coding for various combinations.
2–39
UNILINK HOST ADAPTER
USER MANUAL
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