Skip to content

[FMV] Add support-level table and remove __ARM_ACLE_VERSION #441

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
CarolineConcatto wants to merge 1 commit into
base: main
Choose a base branch
from
Open

[FMV] Add support-level table and remove __ARM_ACLE_VERSION #441

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
109 changes: 74 additions & 35 deletions main/acle.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1499,32 +1499,8 @@ enclose them in parentheses if they are not simple constants.

## Testing for Arm C Language Extensions

`__ARM_ACLE` is defined as the version of this specification that is
implemented, formatted as `{YEAR}{QUARTER}{PATCH}`. The `YEAR` segment is
composed of 4 digits, the `QUARTER` segment is composed of 1 digit, and
the `PATCH` segment is also composed of 1 digit.

For example:

- An implementation based on the version 2023 Q2 of the ACLE with no
further patch releases will define `__ARM_ACLE` as `202320`.
- An implementation based on a hypothetical version 2024 Q3 of the ACLE
with two patch releases will define `__ARM_ACLE` as `202432`.

NOTE: Previously, the macro followed the previous versioning scheme and
was defined as `100 * major_version + minor_version`, which was the
version of this specification implemented. For instance, an implementation
implementing version 2.1 of the ACLE specification defined `__ARM_ACLE`
as `201`.

`__ARM_ACLE_VERSION(year, quarter, patch)` is defined to express a given
ACLE version. Returns with the version number in the same format as the
`__ARM_ACLE` does. Checking the minimum required ACLE version could be
written as:

``` c
#if __ARM_ACLE >= __ARM_ACLE_VERSION(2024, 1, 0)
```
`__ARM_ACLE` is defined to `1` to indicate that the implementation
supports the Arm C Language Extensions.
Comment on lines +1502 to +1503

@paulwalker-arm paulwalker-arm Jul 9, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

For all macros that we are keeping we need to maintain their original value. From the new specification's point of view we just want to say __ARM_ACLE is defined when an implementation supports the ACLE, we just no longer say what it is defined to.

Existing implementation will maintain their current value in order to not break existing code. New implementation can choose whether they care about legacy code or not.


## Endianness

Expand Down Expand Up @@ -2711,7 +2687,7 @@ be found in [[BA]](#BA).
|---------------------------------------------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------|-------------|
| [`__ARM_32BIT_STATE`](#instruction-set-architecture-a32t32a64) | Code is for AArch32 state | 1 |
| [`__ARM_64BIT_STATE`](#instruction-set-architecture-a32t32a64) | Code is for AArch64 state | 1 |
| [`__ARM_ACLE`](#testing-for-arm-c-language-extensions) | Indicates ACLE implemented | 101 |
| [`__ARM_ACLE`](#testing-for-arm-c-language-extensions) | Indicates ACLE implemented | 1 |
| [`__ARM_ALIGN_MAX_PWR`](#alignment-of-static-objects) | Log of maximum alignment of static object | 20 |
| [`__ARM_ALIGN_MAX_STACK_PWR`](#alignment-of-stack-objects) | Log of maximum alignment of stack object | 3 |
| [`__ARM_ARCH`](#arm-architecture-level) | Arm architecture level | 7 |
Expand Down Expand Up @@ -2998,14 +2974,10 @@ following:
versioning mechanism described in this section is supported by the
compiler and it is enabled.

`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is defined to the currently supported
version of the ACLE. The value and the format are the same as the `__ARM_ACLE`.

For example, it can be implemented as:

``` c
#define __FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL __ARM_ACLE_VERSION(2024, 3, 0)
```
`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is defined to the Function
Multi Versioning support level implemented by the compiler. The value
corresponds to the support levels listed in
[Function Multi Versioning feature availability](#function-multi-versioning-feature-availability).

### Target version strings

Expand Down Expand Up @@ -3130,6 +3102,73 @@ The following table lists the architectures feature mapping for AArch64.

The tables are sorted by priority, starting from features of lowest priority ending with features of highest priority.

### Function Multi Versioning feature availability

The following table lists the Function Multi Versioning support level at
which each target version name became available.

A Function Multi Versioning target version name is supported when
`__HAVE_FUNCTION_MULTI_VERSIONING` is defined to `1` and
`__FUNCTION_MULTI_VERSIONING_SUPPORT_LEVEL` is greater than or equal to
the support level listed for that name.

Each new set of Function Multi Versioning target version names added
is assigned a new support level. The new support level is one greater
than the greatest support level already listed. All target version names
added in the same set use the same support level.
Comment on lines +3115 to +3118

@paulwalker-arm paulwalker-arm Jul 9, 2026

Copy link
Copy Markdown

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Perhaps worth being explicit and stating a support level includes all the features of earlier support levels unless specifically documented otherwise.


| **Name** | **Available from support level** |
| ------------- | -------------------------------- |
| default | 202210 |
| sha1 | 202210 |
| aes | 202210 |
| vmull | 202210 |
| rng | 202210 |
| flagm | 202210 |
| flagm2 | 202210 |
| lse | 202210 |
| dotprod | 202210 |
| rdm | 202210 |
| fp16 | 202210 |
| dit | 202210 |
| dpb | 202210 |
| dpb2 | 202210 |
| jscvt | 202210 |
| fcma | 202210 |
| frintts | 202210 |
| sve | 202210 |
| sve2 | 202210 |
| sme | 202210 |
| sb | 202210 |
| ssbs | 202210 |
| bti | 202210 |
| crc | 202240 |
| sha2 | 202240 |
| fp | 202240 |
| simd | 202240 |
| sm4 | 202240 |
| sha3 | 202240 |
| fp16fml | 202240 |
| rcpc | 202240 |
| rcpc2 | 202240 |
| i8mm | 202240 |
| bf16 | 202240 |
| f32mm | 202240 |
| f64mm | 202240 |
| sve2-aes | 202240 |
| sve2-bitperm | 202240 |
| sve2-sha3 | 202240 |
| sve2-sm4 | 202240 |
| memtag | 202240 |
| wfxt | 202240 |
| sme2 | 202240 |
| rcpc3 | 202320 |
| sme-f64f64 | 202320 |
| sme-i16i64 | 202320 |
| rdma | 202410 |
| mops | 202410 |
| cssc | 202520 |

### Dependencies

If a feature depends on another feature as defined by the following table then:
Expand Down
Loading