Name Strings
SPV_KHR_shader_atomic_counter_ops
Contact
To report problems with this extension, please open a new issue at:
Contributors
-
Daniel Koch, NVIDIA
Notice
Copyright (c) 2017 The Khronos Group Inc. Copyright terms at http://www.khronos.org/registry/speccopyright.html
Status
-
Complete
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Approved by the SPIR Working Group: 2017-05-10
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Approved by the Khronos Board of Promoters: 2017-06-30
Version
Last Modified Date |
2017-07-07 |
Revision |
3 |
Dependencies
This extension is written against the SPIR-V Specification, Version 1.1 Revision 7.
This extension requires SPIR-V 1.0.
Overview
This extension provides new capability to allow additional Atomic Instructions on the AtomicCounter Storage Class in order to support the GL_ARB_shader_atomic_counter_ops extension in SPIR-V.
The new functionality is enabled under the AtomicStorageOps capability.
Extension Name
To use this extension within a SPIR-V module, the following OpExtension must be present in the module:
OpExtension "SPV_KHR_shader_atomic_counter_ops"
New Capabilities
This extension introduces a new capability:
AtomicStorageOps
New Builtins
None.
New Instructions
None.
Token Number Assignments
AtomicStorageOps |
4445 |
Modifications to the SPIR-V Specification, Version 1.1
- (Modify Section 3.31, Capability, adding a row to the Capability table)
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Capability Depends On Enabled by Extension 4445
AtomicStorageOps
Uses atomic instructions: OpAtomicIAdd, OpAtomicISub, OpAtomicUMin, OpAtomicUMax, OpAtomicAnd, OpAtomicOr, OpAtomicXor, OpAtomicExchange, or OpAtomicCompareExchange.AtomicStorage
SPV_KHR_shader_atomic_counter_ops
Validation Rules
An OpExtension must be added to the SPIR-V for validation layers to check legal use of this extension:
OpExtension "SPV_KHR_shader_atomic_counter_ops"
Issues
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What should we call the capability?
RESOLVED: AtomicStorageOps. Possible alternatives included AtomicStorageCounterOps or AtomicCounterOps, but this extends the AtomicStorage capability and adds more operations. There are additional operations that still aren’t enabled, but that is a problem for a future extension.
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Should OpAtomicSMin and OpAtomicSMax be supported as well?
RESOLVED: No. The corresponding GLSL built-ins only take uint parameters, so this capability will aim to expose exactly the same set of operations.
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What happened to the Universal Validation Rule about AtomicCounter operations?
RESOLVED: In early versions of SPIR-V (1.0.x for x < 11, and 1.1.y for y < 7) there was a universal validation rule which stated:
Starting with SPIR-V 1.0 version 11 (1.1 version 7) this was moved from a universal validation rule into the AtomicStorage capability.
Revision History
| Rev | Date | Author | Changes |
|---|---|---|---|
1 |
2017-04-25 |
Daniel Koch |
Initial revision |
2 |
2017-05-12 |
David Neto |
Record approval by SPIR Working Group |
3 |
2017-07-07 |
Daniel Koch |
Record ratification |