# VK_EXT_shader_float8(3) Manual Page

## Name

VK_EXT_shader_float8 - device extension

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## Registered Extension Number

568

## Revision

1

## Ratification Status

Not ratified

## Extension and Version Dependencies

None

## API Interactions

- Interacts with VK_KHR_cooperative_matrix

## SPIR-V Dependencies

- SPV_EXT_float8

## Contact

- Kevin Petit [GitHub]kpet

## Extension Proposal

VK_EXT_shader_float8

## Other Extension Metadata

Last Modified Date

  2025-04-16

IP Status

  No known IP claims.

Contributors

  - Kévin Petit, Arm Ltd.

  - Stu Smith, AMD

  - Jeff Bolz, NVIDIA

  - Craig Graham, Samsung

## Description

This extension enables support for 8-bit floating-point data types as defined in SPV_EXT_float8.

## New Structures

- Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:

  - VkPhysicalDeviceShaderFloat8FeaturesEXT

## New Enum Constants

- `VK_EXT_SHADER_FLOAT8_EXTENSION_NAME`

- `VK_EXT_SHADER_FLOAT8_SPEC_VERSION`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_SHADER_FLOAT8_FEATURES_EXT`

If VK_KHR_cooperative_matrix is supported:

- Extending VkComponentTypeKHR:

  - `VK_COMPONENT_TYPE_FLOAT8_E4M3_EXT`

  - `VK_COMPONENT_TYPE_FLOAT8_E5M2_EXT`

## New SPIR-V Capabilities

- Float8EXT

- Float8CooperativeMatrixEXT

## Issues

1) Resolve interactions with the changes VK_KHR_shader_float16 makes to rules for denorm flushing (always allowed by default for all FP formats). How to describe the requirement to preserve subnormals?

+ RESOLVED: Subnormals are always preserved when converting FP8 values to IEEE 754 binary 16. In all other cases, subnormals may be flushed to zero.

+

## Version History

- Revision 1, 2025-04-16 (Kévin Petit)

  - Initial draft

## See Also

No cross-references are available

## Document Notes

For more information, see the Vulkan Specification

This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.

## Copyright

Copyright 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0