From b333b06772c89d96aacb5490d6a219fba7c09cc6 Mon Sep 17 00:00:00 2001
From: Mitja Felicijan <mitja.felicijan@gmail.com>
Date: Thu, 12 Feb 2026 20:57:17 +0100
Subject: Engage!

---
 .../ggml/src/ggml-webgpu/wgsl-shaders/argmax.wgsl  | 72 ++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 llama.cpp/ggml/src/ggml-webgpu/wgsl-shaders/argmax.wgsl

(limited to 'llama.cpp/ggml/src/ggml-webgpu/wgsl-shaders/argmax.wgsl')

diff --git a/llama.cpp/ggml/src/ggml-webgpu/wgsl-shaders/argmax.wgsl b/llama.cpp/ggml/src/ggml-webgpu/wgsl-shaders/argmax.wgsl
new file mode 100644
index 0000000..ca5bfcc
--- /dev/null
+++ b/llama.cpp/ggml/src/ggml-webgpu/wgsl-shaders/argmax.wgsl
@@ -0,0 +1,72 @@
+@group(0) @binding(0)
+#ifdef VEC4
+var<storage, read_write> src: array<vec4<f32>>;
+#define VEC_SIZE 4
+#else
+var<storage, read_write> src: array<f32>;
+#define VEC_SIZE 1
+#endif
+
+@group(0) @binding(1)
+var<storage, read_write> dst: array<i32>;
+
+struct Params {
+    offset_src: u32, // in elements
+    offset_dst: u32, // in elements
+    ne0: u32,
+};
+
+@group(0) @binding(2)
+var<uniform> params: Params;
+
+const FLOAT_MIN: f32 = -1.0e9;
+
+struct Pair {
+    value: f32,
+    index: i32
+};
+
+var<workgroup> shared_max: array<Pair, WG_SIZE>;
+
+@compute @workgroup_size(WG_SIZE)
+fn main(@builtin(workgroup_id) wid: vec3<u32>,
+        @builtin(local_invocation_id) lid: vec3<u32>) {
+    let row_idx = params.offset_src + wid.x * params.ne0;
+    var local_pair = Pair(FLOAT_MIN, -1);
+#ifdef VEC4
+    for (var col = lid.x; col < params.ne0/VEC_SIZE; col += WG_SIZE) {
+        let vec_val = src[row_idx / VEC_SIZE + col];
+        for (var v = 0u; v < VEC_SIZE; v++) {
+            let val = vec_val[v];
+            if (val >= local_pair.value) {
+                local_pair = Pair(val, i32(col * VEC_SIZE + v));
+            }
+        }
+    }
+#else
+    for (var col = lid.x; col < params.ne0; col += WG_SIZE) {
+        if (src[row_idx + col] >= local_pair.value) {
+            local_pair = Pair(src[row_idx + col], i32(col));
+        }
+    }
+#endif
+    shared_max[lid.x] = local_pair;
+    workgroupBarrier();
+    var offset: u32 = WG_SIZE >> 1;
+    while (offset > 0) {
+        if (lid.x < offset) {
+            let a = shared_max[lid.x];
+            let b = shared_max[lid.x + offset];
+            if (b.value > a.value) {
+                shared_max[lid.x] = b;
+            } else if (b.value == a.value && b.index > a.index) {
+                shared_max[lid.x] = b;
+            }
+        }
+        workgroupBarrier();
+        offset >>= 1;
+    }
+    if (lid.x == 0u) {
+        dst[params.offset_dst + wid.x] = shared_max[0].index;
+    }
+}
-- 
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