1 files changed, 56 insertions, 0 deletions
diff --git a/kompute-shaders/op_softmax.comp b/kompute-shaders/op_softmax.comp
new file mode 100644
index 00000000..7bc9176c
--- /dev/null
+++ b/kompute-shaders/op_softmax.comp
@@ -0,0 +1,56 @@
+// TODO: implement multi-simd softmax (llama.cpp commit e16b9fa4)
+
+#version 450
+
+#include "common.comp"
+
+layout(local_size_x_id = 0) in;
+
+layout(binding = 0) buffer restrict readonly tensorInA { float inA[]; };
+layout(binding = 1) buffer restrict readonly tensorInB { float inB[]; };
+layout(binding = 2) buffer restrict writeonly tensorOut { float out_[]; };
+
+layout(push_constant) uniform PushConstants {
+    uint inAOff;
+    uint inBOff;
+    uint outOff;
+    int ne00;
+    int ne01;
+    int ne02;
+    float scale;
+    int mask;
+} pcs;
+
+void main() {
+    if (gl_SubgroupInvocationID > 31)
+        return;
+
+    const uint i03 = gl_WorkGroupID.z;
+    const uint i02 = gl_WorkGroupID.y;
+    const uint i01 = gl_WorkGroupID.x;
+
+    const uint extra_off = i03*pcs.ne02*pcs.ne01*pcs.ne00 + i02*pcs.ne01*pcs.ne00 + i01*pcs.ne00;
+    const uint psrc0 = extra_off + pcs.inAOff; // Based from inA
+    const uint pmask = i01*pcs.ne00 + pcs.inBOff; // Based from inB
+    const uint pdst = extra_off + pcs.outOff; // Based from out_
+
+    // parallel max
+    float localMax = uintBitsToFloat(0xFF800000);
+    for (uint i00 = gl_SubgroupInvocationID.x; i00 < pcs.ne00; i00 += 32) {
+        localMax = max(localMax, inA[psrc0 + i00]*pcs.scale + (pcs.mask!=0 ? inB[pmask + i00] : 0.0f));
+    }
+    float max_ = subgroupMax(localMax);
+
+    // parallel sum
+    float localSum = 0.0f;
+    for (uint i00 = gl_SubgroupInvocationID.x; i00 < pcs.ne00; i00 += 32) {
+        const float exp_psrc0 = exp(inA[psrc0 + i00]*pcs.scale + (pcs.mask!=0 ? inB[pmask + i00] : 0.0f) - max_);
+        localSum += exp_psrc0;
+        out_[pdst + i00] = exp_psrc0;
+    }
+
+    const float sum = subgroupAdd(localSum);
+    for (uint i00 = gl_SubgroupInvocationID.x; i00 < pcs.ne00; i00 += 32) {
+        out_[pdst + i00] /= sum;
+    }
+}