This general macro returns a conversation control block (CCB) entry address
in a specified register when given a CCB identifier.
Format
- label
- A symbolic label may be assigned to this statement.
- REG=Rn
- The variable Rn specifies the register that is to contain the CCB
entry address upon return. The valid range is R1-R7.
- CCBID=ccbid
- The variable ccbid specifies the address of the 4-byte field
containing the CCB ID.
- R|W
- A positional parameter to indicate what type of operation is to be done on
the CCB entry. This parameter corresponds to the read/write parameter
on the CINFC Macro.
- R
- Indicates read only capability is needed. This is the
default.
- W
- Indicates write/update capability is needed.
Entry Requirements
The calling segment must set up addressability of the CCB.
Return Conditions
- Control is returned to the next sequential instruction (NSI).
- The contents of R14 and R15 are unknown. The contents of R0 - R7
are preserved across this macro call.
- The address of the CCB entry is returned in the specified register.
When an error is encountered, the hexadecimal return value in the specified
register is either zeros, indicating a bad CCB ID, or ones, indicating a bad
TCB ID.
Programming Considerations
- This macro can be executed on any I-stream.
- Since the CCBs can be allocated above the 16 megabyte line, the calling
program must be in 31 bit addressing mode.
Examples
- The first invocation identifies R1 as containing the CCB address for
EBW000 upon return. Since the default operation is read access only,
these two examples are the same.
IGTCCB REG=R1,CCBID=EBW000
IGTCCB REG=R1,CCBID=EBW000,R
- This invocation also identifies R1 as containing the CCB address for
EBW000 upon return. In this case EBW000 is to be written or
updated.
IGTCCB REG=R1,CCBID=EBW000,W