DF2912 d_total_size = 512 (512 expected)
DF2912 d_abase      = 0xfffffffffffff200 (underflow shows 0xfffffffffffffe00)
DF2912 d_pbase      = 0x00000000000fe000
DF2912 d_pstop      = 0xffffffffffffe000
# note: d_abase = 512 - 4096 = -3584 = 0xfffffffffffff200 exactly (ressize=4096)