lib: expose Arm features

examples/llama.android/llama/src/main/java/android/llama/cpp/ArmFeatures.kt

@@ -0,0 +1,90 @@
+package android.llama.cpp
+
+/**
+ * Represents an ARM CPU feature with its metadata.
+ */
+data class ArmFeature(
+    val name: String,
+    val displayName: String,
+    val description: String,
+    val armDocUrl: String
+)
+
+/**
+ * Helper class to map LLamaTier to supported ARM features.
+ */
+object ArmFeaturesMapper {
+
+    /**
+     * UI display item combining feature info with support status.
+     */
+    data class DisplayItem(
+        val feature: ArmFeature,
+        val isSupported: Boolean
+    )
+
+    /**
+     * All ARM features supported by the library, in order of introduction.
+     *
+     * TODO-han.yin: fix the broken hyperlinks above!
+     */
+    val allFeatures = listOf(
+        ArmFeature(
+            name = "ASIMD",
+            displayName = "ASIMD",
+            description = "Advanced SIMD (NEON) - baseline vectorization",
+            armDocUrl = "https://developer.arm.com/architectures/instruction-sets/simd-isas/neon"
+        ),
+        ArmFeature(
+            name = "DOTPROD",
+            displayName = "DOTPROD",
+            description = "Dot Product instructions for neural networks",
+            armDocUrl = "https://developer.arm.com/architectures/instruction-sets/intrinsics/dotprod"
+        ),
+        ArmFeature(
+            name = "I8MM",
+            displayName = "I8MM",
+            description = "Integer 8-bit Matrix Multiplication",
+            armDocUrl = "https://developer.arm.com/documentation/102107/latest/Matrix-multiplication-instructions"
+        ),
+        ArmFeature(
+            name = "SVE",
+            displayName = "SVE",
+            description = "Scalable Vector Extension",
+            armDocUrl = "https://developer.arm.com/architectures/instruction-sets/simd-isas/sve"
+        ),
+        ArmFeature(
+            name = "SME",
+            displayName = "SME",
+            description = "Scalable Matrix Extension",
+            armDocUrl = "https://developer.arm.com/architectures/instruction-sets/simd-isas/sme"
+        )
+    )
+
+    /**
+     * Maps a LLamaTier to its supported ARM features.
+     * Returns a list of booleans where each index corresponds to allFeatures.
+     */
+    fun getSupportedFeatures(tier: LLamaTier?): List<Boolean> =
+        when (tier) {
+            LLamaTier.T0 -> listOf(true, false, false, false, false)  // ASIMD only
+            LLamaTier.T1 -> listOf(true, true, false, false, false)   // ASIMD + DOTPROD
+            LLamaTier.T2 -> listOf(true, true, true, false, false)    // ASIMD + DOTPROD + I8MM
+            LLamaTier.T3 -> listOf(true, true, true, true, false)     // ASIMD + DOTPROD + I8MM + SVE
+            // TODO-han.yin: implement T4 once obtaining an Android device with SME!
+            null -> listOf(false, false, false, false, false)         // No tier detected
+        }
+
+    /**
+     * Gets the feature support data for UI display.
+     */
+    fun getFeatureDisplayData(tier: LLamaTier?): List<DisplayItem> =
+        getSupportedFeatures(tier).let { flags ->
+            allFeatures.mapIndexed { index, feature ->
+                DisplayItem(
+                    feature = feature,
+                    isSupported = flags.getOrElse(index) { false }
+                )
+            }
+        }
+}