[LoongArch64] add Intrinsics' API for LoongArch64. by shushanhf · Pull Request #94400 · dotnet/runtime

shushanhf · 2023-11-06T09:41:48Z

We have finished the SIMD on the runtime6.0 and the tests passed.

I will push the SIMD for LoongArch64.

This is the first PR about the API's name.

The [API Proposal]: LoongArch64: add Intrinsics' API for LoongArch64
#94445

@tannergooding
Can you give me some advices ?
Thanks

ghost · 2023-11-06T09:41:55Z

Note regarding the new-api-needs-documentation label:

This serves as a reminder for when your PR is modifying a ref *.cs file and adding/modifying public APIs, please make sure the API implementation in the src *.cs file is documented with triple slash comments, so the PR reviewers can sign off that change.

ghost · 2023-11-06T09:42:00Z

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Issue Details

We have finished the SIMD on the runtime6.0 and the tests passed.

I will push the SIMD for LoongArch64.

This is the first PR about the API's name.

@tannergooding
Can you give me some advices ?
Thanks

Author:	shushanhf
Assignees:	-
Labels:	`area-System.Runtime.Intrinsics`, `new-api-needs-documentation`
Milestone:	-

shushanhf · 2023-11-06T09:44:20Z

@tannergooding
Can you give me some advices ?

This is just the API's name, and first focus on the class name and the API name.

Later I will update this PR to amend some details.

Thanks

huoyaoyuan · 2023-11-06T09:46:52Z

As a new architecture, it's more risky to expose public APIs comparing to mature architectures. I'd suggest keeping them internal, and focusing on cross-platform Vector128/256 intrinsics now.

huoyaoyuan · 2023-11-06T09:50:02Z

For API names, you can open API proposal like #94011. API definition without JIT implementation should be unwanted.

shushanhf · 2023-11-06T09:58:00Z

For API names, you can open API proposal like #94011. API definition without JIT implementation should be unwanted.

If the API is OK for LoongArch64, I will push the JIT implementation.

shushanhf · 2023-11-06T10:03:33Z

As a new architecture, it's more risky to expose public APIs comparing to mature architectures. I'd suggest keeping them internal, and focusing on cross-platform Vector128/256 intrinsics now.

yes, the Vector128/256 is independent of the CPU.

Now the API for architecture is the most important for LoongArch64, I want to confirm them for LoongArch64.
And then I will push all the Hardware-Intrinsics and SIMD.

tannergooding · 2023-11-06T15:04:13Z

+#pragma warning disable IDE0060 // unused parameters
+using System.Runtime.CompilerServices;
+
+namespace System.Runtime.Intrinsics.LoongArch64


I've marked this as NO-MERGE since we cannot take it until after an API review has occurred. See https://github.com/dotnet/runtime/blob/main/docs/project/api-review-process.md

We need an API proposal, following the standard template, created first. We'll have the discussion on relevant name changes and other bits there, then I can then champion that and take it to API review. Once approved, we can then implement the API surface.

Until then, LoongArch would be relegated to only supporting the existing cross platform API surface. For example, Leading/TrailingZeroCount can be supported by accelerating int.Leading/TrailingZeroCount and the same methods on the other primitive types.

Thanks !
Reviewing the API for LoongArch64 based on a PR maybe more clear. So I pushed this PR.
I will create an API proposal for LoongArch64's API.

tannergooding · 2023-11-06T15:19:52Z

+        /// float64x4_t xvfmin_d_f64 (float64x4_t a, float64x4_t b)
+        ///   LASX: XVFMIN.D Xd.4D, Xj.4D, Xk.4D
+        /// </summary>
+        public static Vector256<double> Min(Vector256<double> left, Vector256<double> right) => Min(left, right);


What's the semantics around NaN and -0 handling on LoongArch?

The float operation is implemented within the IEEE-754-2008, here is MinNum(x,y).

tannergooding · 2023-11-06T15:20:37Z

+        /// float32x8_t xvfrecip_s_f32 (float32x8_t a)
+        ///   LASX: XVFRECIP.S Xd.8S Xj.8S
+        /// </summary>
+        public static Vector256<float> Reciprocal(Vector256<float> value) => Reciprocal(value);


Is this exact, or is it an estimate with more than 0.5 ULP error allowed, like on several other platforms?

The Reciprocal is implemented with the IEEE754-2008 division(1.0,x).

Only the FRECIPE and FRSQRTE within the LoongArchBase class are estimate.
But the FRECIP and FRSQRT are exact.

tannergooding · 2023-11-06T15:22:38Z

+        /// bool xvsetnez_v_u8 (uint8x32_t value)
+        ///   LASX: XVSETNEZ.V cd, Xj.32B
+        /// </summary>
+        public static bool HasElementsNotZero(Vector256<byte> value) => HasElementsNotZero(value);


How does this instruction work at the hardware level?

Xj.32B is clearly the input register, but I'm not familiar with cd here. Is it a general purpose register, a flag register, something else?

I will answer these together later.

How does this instruction work at the hardware level?

Xj.32B is clearly the input register, but I'm not familiar with cd here. Is it a general purpose register, a flag register, something else?

The cd is a float flag register which indicating the floats comparing results.
There are 8 cd float flag registers.

Of course here I didn't expose the cd within the API just for simple usage.

Update the API within the LoongArchBase class.

shushanhf · 2023-11-07T03:38:30Z

+    /// </summary>
+    [Intrinsic]
+    [CLSCompliant(false)]
+    public abstract class LoongArchBase


Rename this file as LoongArchBase.cs, is it OK?
Or Just name this file as LABase.cs?

Naming this class as LoongArchBase, is it OK ?

shushanhf · 2023-11-07T03:40:04Z

+            public static int LeadingSignCount(int value) => LeadingSignCount(value);
+
+            /// <summary>
+            ///   LA64: CLO.W rd, rj
+            /// </summary>
+            public static int LeadingSignCount(uint value) => LeadingSignCount(value);


Is it needed to add two types API with int value and uint value ?

shushanhf · 2023-11-07T03:42:28Z

+            public static long ReverseElementBits(int value) => ReverseElementBits(value);
+
+            /// <summary>
+            ///   LA64: BITREV.W rd, rj
+            /// </summary>
+            public static ulong ReverseElementBits(uint value) => ReverseElementBits(value);


Is it needed to add the int value and uint value for the API ReverseElementBits() ?

shushanhf

@tannergooding

shushanhf · 2023-11-07T03:52:20Z

+            public static int ReverseElementBits(int value) => ReverseElementBits(value);
+
+            /// <summary>
+            ///   LA64: REVB.2W rd, rj
+            /// </summary>
+            public static uint ReverseElementBits(uint value) => ReverseElementBits(value);
+
+            /// <summary>
+            ///   LA64: REVB.D rd, rj
+            /// </summary>
+            public static long ReverseElementBits(long value) => ReverseElementBits(value);
+
+            /// <summary>
+            ///   LA64: REVB.D rd, rj
+            /// </summary>
+            public static ulong ReverseElementBits(ulong value) => ReverseElementBits(value);


These are part of instructions liking the Arm64's REV, REV16, REV32, REV64, but the ArmBase class doesn't support these, Why?

Is it needed to add these for LoongArch64.

Sign-Zero-extend and MultiplyWiden

bitwise shift, shuffle, compare and float operations.

add LoadElementReplicateVector, Vector elements' operations and AverageRounded.

shushanhf · 2023-11-29T09:50:45Z

Hi, @tannergooding
I finished the first version of this PR, could you please review this PR?
Thanks

….cs.

tannergooding · 2023-11-30T15:35:04Z

could you please review this PR?

I can potentially give it a pass today or tomorrow, but its still blocked until API review can happen. That probably won't happen until the new year as API review typically doesn't happen in December when most people are on holiday/vacation.

shushanhf · 2023-12-01T00:56:50Z

could you please review this PR?

I can potentially give it a pass today or tomorrow, but its still blocked until API review can happen. That probably won't happen until the new year as API review typically doesn't happen in December when most people are on holiday/vacation.

OK, Thanks
I can wait more reviewers.

I will push other PRs that are independent of these APIs liking the SIMD's instructions within the emitter #95456

Also amend some code-formate.

tannergooding · 2024-01-29T16:12:15Z

I'm still waiting for response to the question asked on the API proposal:

Where is the spec for the LA64 SIMD ISA?

Based on https://loongson.github.io/LoongArch-Documentation/README-EN.html, it looks like it should be Volume 2, but there doesn't appear to be any version published for it yet and the backing GitHub repo looks to be archived now and I do not see a replacement.

shushanhf · 2024-01-30T01:32:44Z

I'm still waiting for response to the question asked on the API proposal:

Where is the spec for the LA64 SIMD ISA?
Based on https://loongson.github.io/LoongArch-Documentation/README-EN.html, it looks like it should be Volume 2, but there doesn't appear to be any version published for it yet and the backing GitHub repo looks to be archived now and I do not see a replacement.

I'm very sorry for late response.
In fact the Loongson does't publish the offical Intrinsic manual of English Version yet.

Although the GCC had merged the LoongArch's SIMD.
https://github.com/gcc-mirror/gcc/blob/master/gcc/config/loongarch/lsxintrin.h
https://github.com/gcc-mirror/gcc/blob/master/gcc/config/loongarch/lasxintrin.h

And the LLVM is same.

There is an unofficial intrinsics manual:
https://github.com/jiegec/unofficial-loongarch-intrinsics-guide?tab=readme-ov-file
https://jia.je/unofficial-loongarch-intrinsics-guide/

tannergooding · 2024-01-30T17:30:57Z

Thanks! This is still on my backlog but is lower priority than some other work due to the API review not having happened yet (and this PR being blocked until that can happen).

I'll try to set some time aside in the next week or two to go through the SIMD ISA guide and compare it to the proposed API surface so that it can get marked ready-for-review

shushanhf · 2024-01-31T00:54:07Z

Thanks! This is still on my backlog but is lower priority than some other work due to the API review not having happened yet (and this PR being blocked until that can happen).

I'll try to set some time aside in the next week or two to go through the SIMD ISA guide and compare it to the proposed API surface so that it can get marked ready-for-review

OK, Thanks very much.
I will do it after the Feb. 17 for the Chinese Spring Festival.

steveisok · 2025-09-29T20:30:40Z

@tannergooding what is the status of this review?

tannergooding · 2025-09-29T20:54:11Z

As per the above, new public API surface cannot be added without it first going through API Review.

Last checked, the LoongArch specs weren't available or were still in draft form, so going to API review wasn't possible.

If that's changed, then it'd be great to have links and references to the official docs so I can help drive this through to completion.

dotnet-policy-service · 2025-10-30T02:54:13Z

Draft Pull Request was automatically closed for 30 days of inactivity. Please let us know if you'd like to reopen it.

[LoongArch64] add Intrinsics' API for LoongArch64.

9e4e754

ghost added area-System.Runtime.Intrinsics new-api-needs-documentation labels Nov 6, 2023

ghost added the community-contribution Indicates that the PR has been added by a community member label Nov 6, 2023

shushanhf commented Nov 6, 2023

View reviewed changes

Comment thread ...m.Private.CoreLib/src/System/Runtime/Intrinsics/LoongArch64/LA64Base.PlatformNotSupported.cs Outdated

shushanhf commented Nov 6, 2023

View reviewed changes

Comment thread src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/LoongArch64/LA_LASX.cs Outdated

tannergooding added the NO-MERGE The PR is not ready for merge yet (see discussion for detailed reasons) label Nov 6, 2023

tannergooding reviewed Nov 6, 2023

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Comment thread src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/LoongArch64/LA64Base.cs Outdated

shushanhf mentioned this pull request Nov 7, 2023

[API Proposal]: LoongArch64: add Intrinsics' API for LoongArch64 #94445

Open

Rename LA64Base -> LoongArchBase, LA_LSX -> Lsx, LA_LASX -> Lasx.

5c601e1

Update the API within the LoongArchBase class.

shushanhf commented Nov 7, 2023

View reviewed changes

Lsx-PartA: add some APIs for Lsx.

6e3a9e7

shushanhf force-pushed the LA_SIMD_API branch from 19f78ff to 6e3a9e7 Compare November 10, 2023 08:36

Lsx-PartB, Lasx-PartA: add some bitwise ops, MultiplyHight, Mod,

1e7203a

Sign-Zero-extend and MultiplyWiden

shushanhf force-pushed the LA_SIMD_API branch from 2a527ef to 1e7203a Compare November 16, 2023 10:50

shushanhf added 3 commits November 24, 2023 18:00

Lsx-PartE, Lasx-PartD: add some add/madd operations, max/min,

fc8d982

bitwise shift, shuffle, compare and float operations.

Lsx-PartF, Lasx-PartE: amend the Load/Store Vector128/256,

9c0c631

add LoadElementReplicateVector, Vector elements' operations and AverageRounded.

LoongArchBase: add CRC-32 and some float operations.

2bbf4d1

shushanhf force-pushed the LA_SIMD_API branch from 008722b to 8739f1b Compare November 29, 2023 09:41

shushanhf force-pushed the LA_SIMD_API branch 6 times, most recently from 424a8a1 to 411b9f5 Compare November 30, 2023 03:20

update the *PlatformNotSupported.cs and ref/System.Runtime.Intrinsics…

6c7b380

….cs.

shushanhf force-pushed the LA_SIMD_API branch from 411b9f5 to 6c7b380 Compare November 30, 2023 03:31

add VectorSaturate and VectorSaturateUnsigned.

952a76b

Also amend some code-formate.

shushanhf force-pushed the LA_SIMD_API branch from b260975 to 952a76b Compare December 7, 2023 13:01

am11 added the arch-loongarch64 label Dec 30, 2023

tannergooding self-assigned this Jan 30, 2024

LuckyXu-HF mentioned this pull request Jun 6, 2024

[LoongArch64] Fix the TestVector256() size alignment within src/tests/Interop/StructPacking/StructPacking.cs. #103112

Merged

jkotas marked this pull request as draft September 29, 2025 21:37

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