Use this system macro to return the total number of certain storage blocks
allocated by the TPF system. The size of the physical data table and
the equate for the block are used to determine the size. The
allocations of traditional TPF blocks (L0 or 128, L1 or 381, L2 or 1055, L4 or
4 K) can not be queried because these block are not implemented as independent
block types. The block types supported are LIOCB, LECB (L3), LSWB,
LCOMMON, and LFRAME.
Required Authorizations
|
Key0
| Restricted
| System
| Common Storage
|
| X
|
|
|
Format
- TYPE=Rn
- The register that contains the physical storage block type equate.
R0 is not valid for all calls and R8 through R13 are not valid for all E-type
calls.
Valid types, as defined in CLHEQ, are:
- LIOCB
- I/O control block
- LECB
- Entry control block (ECB)
- LSWB
- System work block (SWB)
- LCOMMON
- Shared working storage block
- LFRAME
- ECB unique working storage block
The MAXBC macro does not support logical blocks carved from other
blocks. The block type values for MAXBC that are not valid follow
here.
- L0
- 128 Byte Block
- L1
- 381 Byte Block
- L2
- 1055 Byte Block
- L4
- 4 K Block
Entry Requirements
- The register specified on the TYPE parameter must contain the value for
the block type desired.
- R0 cannot be specified.
- For E-type programs R10 must be available as a scratch register.
Return Conditions
- Control is returned to the next sequential instruction (NSI).
- The register specified on the TYPE parameter contains the number of blocks
allocated for the specified block type. The contents of all other
registers are preserved across this macro call.
- The condition code is not saved across the macro call.
- If the block type requested is determined to be in error at run time, the
00074D system error is issued and the ECB is exited.
Programming Considerations
- This macro can be run on any I-stream.
- This macro may be called by E-type programs or from control program (CP)
code.
- R0 cannot be specified for the TYPE parameter.
- All logical blocks are carved from 4 K blocks. Because of this, it
is impossible to specify the number of available storage blocks, except 4 K
blocks, at any given point.
- The usage of the MAXBC macro requires authorization to issue a restricted
macro (CHECK=RESTR) by the $CKMAC macro.
- A system error dump can occur when servicing a MAXBC request.
See Messages (System Error and Offline) for more
information.
Examples
None.