The following sections of the section provide details of the individual
XPI function calls. The description of each function defines only the options
that are specific to that call. Options that are applicable to all function
calls are described in Making an XPI call. The following argument types
are used:
- name1, name2,....
- Each of these refers to the name of a field of the given size in bytes. "name1"
means that the name you specify should be that of a 1-byte field.
- literalconst
- A number in the form of a literal, for example B'00000000', X'FF', X'FCF4', "0", or an equate symbol with a similar
value.
- expression
- A valid assembler-language expression: a decimal integer, or any arithmetic
expression (including symbolic values) valid in assembler language; for example:
20; L'AREA; L'AREA+10; L'AREA+X'22'; SYMB/3+20 .
- (Rn)
- A register reference. The parentheses shown here are required in addition
to those that surround the argument. For example: OPTION((R5)).
- block-descriptor
- Represents a source of both the data address and the data length fields.
A block-descriptor can be either a single value or a double value. The following
is the single-value form:
OPTION(blkdname)
- blkdname
- The name of a block-descriptor. A pair of contiguous fullwords, in which
the first word contains the address of the data, and the second word contains
the length in bytes of the data, as a fullword binary value. Register notation
is not accepted for this single-value form.
The following is the double-value form:
OPTION(addr,len)
- addr
- The data address as {namea | (Ra) | aliteral}:
- namea
- The name of a location containing the data address
- (Ra)
- A register containing the data address
- aliteral
- An address constant literal; for example: A(data).
- len
- The data length as {namel | (Rn) | expression}:
- namel
- The name of a location containing a binary fullword giving the data
length in bytes
- (Rn)
- A register, the contents of which specify in fullword binary the number
of bytes of data
- expression
- A decimal integer, or any arithmetic expression, including symbolic
values, valid in assembler language; for example:
L'AREA ; L'AREA+10 ; L'AREA+X'22' ; SYMB/3+20 .
- buffer-descriptor
- Represents a source of both the data address and the maximum data length
fields. Parts of the buffer-descriptor are also reserved to act as receiving
fields for output information. A buffer-descriptor can be either a single
value or a multiple value. The following is the single-value form:
OPTION(bufdname)
- bufdname
- The name of a buffer-descriptor. A group of four contiguous fullwords,
in which:
- The first word contains the address of the data (input).
- The second word is reserved to receive the current length in bytes of
the data, as a fullword binary value (output).
- The third word contains the maximum length in bytes of the data, as a
fullword binary value (input).
- The fourth word is reserved for use by the XPI.
Register notation is not accepted for this single-value form.
The following is the multiple-value form:
OPTION(addr,maxlen,*)
- addr
- The data address as {namea | (Ra) | aliteral}:
- namea
- The name of a location containing the data address
- (Ra)
- A register containing the data address
- aliteral
- An address constant literal, for example, A(data).
- maxlen
- The maximum data length as {namel | (Rn) | expression}:
- namel
- The name of a location containing a binary fullword giving the maximum
data length in bytes
- (Rn)
- A register, the contents of which specify in fullword binary the maximum
number of bytes of data
- expression
- A decimal integer, or any arithmetic expression, including symbolic
values, valid in assembler language; for example:
L'AREA ; L'AREA+10 ; L'AREA+X'22' ; SYMB/3+20 .
- *
- A required parameter to indicate that the parameter list is to be used
for the reserved fields.

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