diff --git a/src/panfrost/encoder/pan_invocation.c b/src/panfrost/encoder/pan_invocation.c
new file mode 100644
index 0000000..810fed3
--- /dev/null
+++ b/src/panfrost/encoder/pan_invocation.c
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2019 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ * Authors (Collabora):
+ *   Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
+ *
+ */
+
+#include <assert.h>
+#include "util/u_math.h"
+#include "pan_encoder.h"
+
+/* Compute shaders are invoked with a gl_NumWorkGroups X/Y/Z triplet. Vertex
+ * shaders, it turns out, are invoked with the same mechanism, with the triplet
+ * (1, vertex_count, instance_count).
+ *
+ * Alongside this triplet is the gl_WorkGroupSize X/Y/Z triplet.
+ *
+ * Unfortunately, the packing for these triplet into the
+ * mali_vertex_tiler_prefix is a little funky, using a dynamic bitfield. The
+ * routines here exist to pack this */
+
+void
+panfrost_pack_work_groups_compute(
+        struct mali_vertex_tiler_prefix *out,
+        unsigned num_x,
+        unsigned num_y,
+        unsigned num_z,
+        unsigned size_x,
+        unsigned size_y,
+        unsigned size_z)
+{
+        /* First of all, all 6 values are off-by-one (strictly positive).
+         * Account for that, first by ensuring all values are strictly positive
+         * and then by offsetting */
+
+        assert(num_x > 0);
+        assert(num_y > 0);
+        assert(num_z > 0);
+
+        assert(size_x > 0);
+        assert(size_y > 0);
+        assert(size_z > 0);
+
+        num_x = MALI_POSITIVE(num_x);
+        num_y = MALI_POSITIVE(num_y);
+        num_z = MALI_POSITIVE(num_z);
+
+        size_x = MALI_POSITIVE(size_x);
+        size_y = MALI_POSITIVE(size_y);
+        size_z = MALI_POSITIVE(size_z);
+
+        /* Next up is to pack in order */
+
+        uint32_t packed = 0;
+
+        /* The values needing packing, in order, and the corresponding shifts.
+         * Indicies into shift are off-by-one to make the logic easier */
+
+        unsigned shifts[7] = { 0 };
+        unsigned values[6] = { size_x, size_y, size_z, num_x, num_y, num_z };
+
+        for (unsigned i = 0; i < 6; ++i) {
+                /* OR it in, shifting as required */
+                packed |= (values[i] << shifts[i]);
+
+                /* How many bits did we use? */
+                unsigned bit_count = util_logbase2_ceil(values[i] + 1);
+
+                /* Set the next shift accordingly */
+                shifts[i + 1] = shifts[i] + bit_count;
+        }
+
+        /* We're packed, so upload everything */
+        out->invocation_count = packed;
+        out->size_y_shift = shifts[1];
+        out->size_z_shift = shifts[2];
+        out->workgroups_x_shift = shifts[3];
+        out->workgroups_y_shift = shifts[4];
+        out->workgroups_z_shift = shifts[5];
+
+        /* Special fields */
+        out->workgroups_x_shift_2 = MAX2(out->workgroups_x_shift, 2);
+        out->workgroups_x_shift_3 = out->workgroups_x_shift_2;
+}
+
+/* Packs vertex/tiler descriptors simultaneously */
+void
+panfrost_pack_work_groups_fused(
+        struct mali_vertex_tiler_prefix *vertex,
+        struct mali_vertex_tiler_prefix *tiler,
+        unsigned num_x,
+        unsigned num_y,
+        unsigned num_z,
+        unsigned size_x,
+        unsigned size_y,
+        unsigned size_z)
+{
+        panfrost_pack_work_groups_compute(vertex, num_x, num_y, num_z, size_x, size_y, size_z);
+
+        /* Copy results over */
+        tiler->invocation_count = vertex->invocation_count;
+        tiler->size_y_shift = vertex->size_y_shift;
+        tiler->size_z_shift = vertex->size_z_shift;
+        tiler->workgroups_x_shift = vertex->workgroups_x_shift;
+        tiler->workgroups_x_shift_2 = vertex->workgroups_x_shift_2;
+        tiler->workgroups_y_shift = vertex->workgroups_y_shift;
+        tiler->workgroups_z_shift = vertex->workgroups_z_shift;
+
+        /* Set special fields for each */
+        vertex->workgroups_x_shift_3 = 5;
+        tiler->workgroups_x_shift_3 = 6;
+}
+