opencl: support bf16 by converting to f16 (#23839)

2026-05-30 10:17:47 -07:00
parent d38d50e7ff
commit d6588daa80
2 changed files with 121 additions and 2 deletions
@@ -117,6 +117,48 @@ struct block_iq4_nl
    uint8_t qs[QK4_NL / 2];
 };

+//------------------------------------------------------------------------------
+// bf16 to f16
+//------------------------------------------------------------------------------
+kernel void kernel_convert_bf16_to_f16(
+    global const ushort * src,
+    global half * dst,
+    ulong off_dst,
+    ulong n
+) {
+    uint i = get_global_id(0);
+    if (i >= n) {
+        return;
+    }
+
+    dst[i + off_dst] = (half) as_float((uint) src[i] << 16);
+}
+
+//------------------------------------------------------------------------------
+// f16 to bf16
+//------------------------------------------------------------------------------
+kernel void kernel_convert_f16_to_bf16(
+    global const half * src,
+    ulong off_src,
+    global ushort * dst,
+    ulong n
+) {
+    uint i = get_global_id(0);
+    if (i >= n) {
+        return;
+    }
+
+    float f = (float) src[i + off_src];
+    uint bits = as_uint(f);
+    if ((bits & 0x7fffffffu) > 0x7f800000u) {
+        // nan to quiet nan
+        dst[i] = (ushort)((bits >> 16) | 0x40u);
+    } else {
+        uint rounded = bits + 0x7fffu + ((bits >> 16) & 1u);
+        dst[i] = (ushort)(rounded >> 16);
+    }
+}
+
 //------------------------------------------------------------------------------
 // kernel_convert_block_q4_0
 // Convert the block_q4_0 format to 2 separate arrays (AOS -> SOA).