Below is an algorithm for Readers$-$Writers problem. Fill in the table of the values of semaphores or variables.

Shared data

semaphore mutex, db;

Initially

mutex $=1,$ db $=1,$ readcount $=0$

Writer process:

wait$($db$)$;

$...$

writing is performed

$...$

signal$($db$)$;

Reader process:

wait$($mutex$)$;

readcount$++$;

if $($readcount $==1)$

wait$($db$)$;

signal$($mutex$)$;

$...$

reading is performed

$...$

wait$($mutex$)$;

readcount$--$;

if $($readcount $==0)$

signal$($db$)$;

signal$($mutex$)$:

event mutex db readcount

a writer comes

a reader comes

a writer has done

a reader comes

a reader comes

a writer comes

a reader has done

a reader has done

a reader has done

a writer comes