ldrh temp, [ psx_gpu, #psx_gpu_num_spans_offset ]
add temp, temp, height_minor_b
+
+ cmp temp, #MAX_SPANS
+ beq 5f
+
strh temp, [ psx_gpu, #psx_gpu_num_spans_offset ]
2:
setup_spans_prologue_b()
bal 4b
+ 5:
+ // FIXME: overflow corner case
+ sub temp, temp, height_minor_b
+ bics height_minor_b, #3
+ add temp, temp, height_minor_b
+ strh temp, [ psx_gpu, #psx_gpu_num_spans_offset ]
+ bne 2b
+ bal 1b
+
.pool
#undef span_uvrg_offset