db> show registers
at          ffffffffffffffc0
v0          7
v1          7
a0          0
a1          ff00
a2          0
a3          ffffffff80680000    ostype+0x35450
a4          f4240
a5          ffffffff80640000    CSWTCH.41+0x80
a6          33
a7          fffffffffffffffe
t0          ffffffffffffffff
t1          1
t2          ffffffff80746b80    cpu_info_store
t3          0
s0          9800000410a03b80
s1          ffffffff807531f0    th0
s2          980000041feeae00
s3          980000041feeae00
s4          9800000410a03b20
s5          980000041f9b4500
s6          3
s7          9800000410a03c00
t8          980000041f9b4080
t9          ffffffff804a04e8    devnullop
k0          20
k1          ffffffff80746b80    cpu_info_store
gp          ffffffff8081d170    si_lock
sp          9800000410a03ac0
fp          2
ra          0
sr          80ff83
mdlo        1d0c804102ff9442
mdhi        83b
bad         980000041feeae00
cs          8
pc          0
0:      address 0x0 is invalid
nop