SVC 4 (0A04)

GETMAIN macro - is type 1, gets LOCAL lock.

Calls module IGVVSM24, entry point IGC004.

Note: The GETMAIN/FREEMAIN interface provided by SVC 4 can be called in either 24- or 31-bit addressing mode. Storage area addresses and lengths are treated as 24-bit addresses and values. If the caller's addressing mode is 31-bit, the parameter list address and the pointers to the length and address lists in the parameter list, if present, are treated as 31-bit addresses. Otherwise, they are treated as 24-bit addresses with the high byte of the address ignored.

GTF data is:

R15 and R0

No applicable data.

R1

Address of the parameter list passed when the SVC was called.

PLIST

10 bytes in length; bytes are as follows:

Bytes
0-3	a.	Single area request - length requested.
	b.	Variable request - address of a doubleword containing the minimum maximum length requested. Format is: Bytes 0 Zero. 1-3 Minimum length. 4 Zero. 5-7 Maximum length.
	c.	List request - address of a list of lengths requested (one word per request); last word contains X'80' in byte 0.
4	Zero
5-7	a.	Single area request - address of a word GETMAIN initializes with the address of the area acquired.
	b.	Variable area request - address of a doubleword GETMAIN initializes with the address of the area acquired and the actual length allocated.
	c.	List request - address of a list of areas that GETMAIN initializes with the addresses of the areas allocated for each requested length in the length list.
8	Flag byte, format is:
	10	Request is for storage aligned on a page boundary.
	00	Unconditional single area request.
	20	Conditional single area request.
	80	Unconditional list request.
	A0	Conditional list request.
	C0	Unconditional variable request.
	E0	Conditional variable request.
9	Subpool identification.

R1

unchanged.

R15

00, if storage is available.
04, if storage is not available.