You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
30 lines
476 B
30 lines
476 B
.var ticket
|
|
.var turn
|
|
.var count
|
|
|
|
.main
|
|
.top
|
|
|
|
.acquire
|
|
mov $1, %ax
|
|
fetchadd %ax, ticket # grab a ticket (keep it in dx)
|
|
.tryagain
|
|
mov turn, %cx # check if it's your turn
|
|
test %cx, %ax
|
|
jne .tryagain
|
|
|
|
# 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 $1, %ax
|
|
fetchadd %ax, turn
|
|
|
|
# see if we're still looping
|
|
sub $1, %bx
|
|
test $0, %bx
|
|
jgt .top
|
|
|
|
halt
|