ARM 7 – Pipelining, Operating
Modes & Interrupts
Pipelining Time Estimation
So similarly is I say 100 cycles is to executed
Normal Processor = 100 x 3 = 300 cycle
Pipeline 3 stage
N instruction size = 100
N-1 = 99
K = 3 for first instruction
Time = K+(N-1) = 3 + 99 = 102
So true pipeline = 1/3 time
So ARM is 3 times faster
ARM 7 pipelining ( cont…)
ARM 7 pipelining ( cont…)
Operating Modes (1)
BIOS OS
Privilege mode:
System has the privilege to access user prog and data
But user will never have the privilege of accessing system program
freely until demanded.
Case example: User decided to install an application(APP).
APP asks privileges to access system data or user data ?
Operating Modes (2)
In user mode: Installation of APPS when user decided requires a privilege so that that APP can
access certain SYSTEM parts to install and leave its footprints.
Operating Modes (3)
System Call is utilised to enter in this low level
Privileged version of user mode which requires
Certain privileges but not the complete privileges
Example: rearranging APPS on the phone.
“You are the installing new but simply rearranging”
Operating Modes (4)
Operating Modes (4)
Operating Modes (4)
Abort : Clash between your program and system.
I.E. when a user program tries to access the
System program on error its called prefetch abort
And when user access System data and error occurs its
Called Data abort.
Operating Modes (5)
When operation code cannot be
Understood by the microcontroller
Then at the debugger mode the
System needs to kill the complete
Program.
INTERRUPTS/EXCEPTION
ISR ON EXCEPTION
INTERRUPTS DETAILS…..
INTERRUPTS DETAILS…..(CONT)
INTERRUPTS DETAILS…..(CONT)
PRIORITY OF INTERRUPTS