+ /**
+ * We can't set the VDECL offset to something negative, so we
+ * must calculate a common negative additional index bias, and modify
+ * the VDECL offsets accordingly so they *all* end up positive.
+ *
+ * Note that the exact value of the negative index bias is not that
+ * important, since we compensate for it when we calculate the vertex
+ * buffer offset below. The important thing is that all vertex buffer
+ * offsets remain positive.
+ *
+ * Note that we use a negative bias variable in order to make the
+ * rounding maths more easy to follow, and to avoid int / unsigned
+ * confusion.
+ */
+
+ for (i = 0; i < svga->curr.velems->count; i++) {
+ const struct pipe_vertex_buffer *vb =
+ &svga->curr.vb[ve[i].vertex_buffer_index];
+ struct svga_buffer *buffer;
+ unsigned int offset = vb->buffer_offset + ve[i].src_offset;
+ unsigned tmp_neg_bias = 0;
+
+ if (!vb->buffer.resource)
+ continue;
+
+ buffer = svga_buffer(vb->buffer.resource);
+ if (buffer->uploaded.start > offset) {
+ tmp_neg_bias = buffer->uploaded.start - offset;
+ if (vb->stride)
+ tmp_neg_bias = (tmp_neg_bias + vb->stride - 1) / vb->stride;
+ neg_bias = MAX2(neg_bias, tmp_neg_bias);
+ }
+ }