《操作系统》的实验代码。
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27 lines
480 B

.var flag
.var count
.main
.top
.acquire
mov flag, %ax # get flag
test $0, %ax # if we get 0 back: lock is free!
jne .acquire # if not, try again
mov $1, flag # store 1 into flag
# critical section
mov count, %ax # get the value at the address
add $1, %ax # increment it
mov %ax, count # store it back
# release lock
mov $0, flag # clear the flag now
# see if we're still looping
sub $1, %bx
test $0, %bx
jgt .top
halt