Remove the following files to restore the state of the filesystem,
so subsequent tests don't fail unexpectedly by creating same filename.

q0             2 21 0
q?             2 22 0
q;             2 23 0
qC             2 24 0
q=             2 25 0
qA             2 26 0
q:             2 27 0
q<             2 28 0
q>             2 29 0
q@             2 30 0
qB             2 31 0
r0             2 32 0
r?             2 33 0
r;             2 34 0
rC             2 35 0
r=             2 36 0
rA             2 37 0
r:             2 38 0
r<             2 39 0
r>             2 40 0
r@             2 41 0
rB             2 42 0
s0             2 43 0
s?             2 44 0
s;             2 45 0
sC             2 46 0
s=             2 47 0
sA             2 48 0
s:             2 49 0
s<             2 50 0
s>             2 51 0
p?             2 52 0
p;             2 53 0
pC             2 54 0
p=             2 55 0
pA             2 56 0
p:             2 57 0
p<             2 58 0
p>             2 59 0
p@             2 60 0
pB             2 61 0
s@             2 62 0
sB             2 63 0

The variable `n` represents the number of blocks that have been read.

added read of register ISR to clear interrupt source of UART16550.

It might be too paranoid but makes it safe to deal with operators
with lower priorities than '+', '<<' for example.

this requires qemu version >= 7.2.

add %ld %lld %u %lu %llu %lx %llx to kernel and user printf

interrupts are always off (i.e. a lock is held) any time the
current process is not in RUNNING state.

most recent process to run, so it must explicitly
turn them on again. It would be better if cpu->intena
were really thread->intena.

the locking scheme from long ago.

61810

memory, out of disk space, or test big directories.

Support -q option to run only the quick tests, which saves about
7mins.

Clean up driver by removing duplicated code.