Generate Universal Unique Identifier (GENUUID)

Op Code (Hex)	Operand 1
011D	UUID return template

Operand 1: Space pointer.

Bound program access
Built-in number for GENUUID is 461. GENUUID ( UUID_return_template : address )

Description

This instruction generates a universal unique identifier and returns it in the template provided. The UUID is unique as an identifier across all time and space and is consistent with the Open Systems Foundation (OSF) Distributed Computing Environments (DCE) version 1 UUID specification described in the DCE's "Architecture Environment Specification/Distributed Computing: for Remote Procedure Calls", Appendix A. The template identified by operand 1 must be 16 byte aligned. The 16 byte Universal Unique Identifier (UUID) is returned in the UUID return template.

The UUID return template (operand 1) has the following format:

Offset
Dec	Hex	Field Name		Data Type and Length
0	0	Return template size specification		Char(8)
0	0		Number of bytes provided		UBin(4)
4	4		Number of bytes available		UBin(4)
8	8	Reserved (binary 0)		Char(8)
16	10	Returned UUID		Char(16)
32	20	--- End ---

The first 4 bytes of the template identify the total number of bytes provided for use by the instruction. The value is supplied as input to the instruction and is not modified by the instruction. A value of less than 32 causes a template size invalid (hex 3802) exception to be signaled.

The second 4 bytes of the template identify the total number of bytes available to be returned. This value is output. The value is the size of the template.

The reserved field must be set to zeros or a template value invalid (hex 3801) exception will be signaled.

The returned UUID field contains the generated UUID. The UUID is a DCE version 1 UUID.

Note: There are certain restrictions on the UUID that should be remembered:

Operations on the UUID should be limited to:
- Equality comparison (equal or not equal)
- Lexical ordering - UUIDs can be ordered based on the most significant byte that differs between the compared UUIDs.
- String conversion - based on the DCE architecture string representation of a UUID.

Authorization Required

None

Lock Enforcement

None

Exceptions

06 Addressing

0601 Space Addressing Violation
0602 Boundary Alignment

08 Argument/Parameter

0801 Parameter Reference Violation

20 Machine Support

2002 Machine Check
2003 Function Check

24 Pointer Specification

2401 Pointer Does Not Exist
2402 Pointer Type Invalid

32 Scalar Specification

3201 Scalar Type Invalid

38 Template Specification

3801 Template Value Invalid
3802 Template Size Invalid

44 Protection Violation

4401 Object Domain or Hardware Storage Protection Violation
4402 Literal Values Cannot Be Changed