gtps1m0jSystem Macros

$GCOMC-Obtain Common Storage Block

Use this system macro to obtain a storage block from the pool of working storage that is accessed at the same address in any address space.

Format




label
A symbolic name can be assigned to the macro statement.

BLOCK=Ri
This parameter is used to return the block address. The register specified is loaded with the storage block address on return from the service routine. The block is allocated below 16 MB. The block address is correct in 24-or 31-bit mode and in any address space. Any general purpose register, with the exception of stack register R13, can be used for this parameter.

FORMAT=Rj
This parameter is used to specify the format flag to be placed in the block. The register specified contains the block format flag in the rightmost (low-order) byte. Any general purpose register, with the exception of stack register R13, can be used for this parameter.

TYPE=Rk
This parameter specifies the storage block type requested. The register specified in this input parameter contains the logical storage block type equate value in the low-order (rightmost) byte. The block equate is restricted to blocks that can be placed on an ECB core block reference word (L0, L1, L2, or L4). Any general purpose register, with the exception of stack register R13, can be used for this parameter.

ECB
This parameter indicates which address will be saved in the common block control table.

YES
Indicates the SVA of the ECB (CE2SVA) is to be saved in the CCTECB field of the common control tree table (IDSCCT)

NO
Indicates that the address of the caller (in R14) should be saved in the CCTECB field.

SAVREG
The specified volatile registers will be saved by the macro in the stack area or in the registers specified by the WKREG parameter. Up to 3 registers can be specified. Those registers are R0, R1, R2. If this keyword is omitted, none of the 3 registers will be saved. You should not save a volatile register if you expect it to contain an output parameter. The register will be overwritten with its original contents, since the reload is the last thing performed by the macro.

WKREG
The specified symbolic register names are free to be used by the macro to save the volatile registers coded on the SAVREG parameter. Up to 3 registers can be specified, but the standard linkage registers R13 through R2 cannot be used here. This parameter is used in conjunction with the SAVREG parameter to generate efficient code and enhance the performance of the macro. The number of registers specified by WKREG should be less than or equal to the number of registers specified by SAVREG. If this parameter is omitted or not used to its maximum capacity, code optimization is sacrificed.

Entry Requirements

Return Conditions

Programming Considerations

The most efficient use of this macro can be accomplished by using the WKREG parameter with the SAVREG parameter.

Examples

None.