As per some document reference that I found on net the expected vector table generated by assembler is give below
__Vectors DCD __initial_sp ; Top of Stack DCD Reset_Handler ; Reset Handler DCD NMI_Handler ; NMI Handler [...more vectors...]
00000000 LDR PC, =__initial_sp 00000004 LDR PC, =Reset_Handler 00000008 LDR PC, =NMI_Handler
but if we see actual code, it will be like
0x00000000 0268 LSLS r0,r5,#9 0x00000002 1000 ASRS r0,r0,#0 0x00000004 0169 LSLS r1,r5,#5 0x00000006 0000 MOVS r0,r0 0x00000008 0171 LSLS r1,r6,#5 0x0000000A 0000 MOVS r0,r0 0x0000000C 0173 LSLS r3,r6,#5 0x0000000E 0000 MOVS r0,r0
Any idea where will be the vector table?
Thanks
It's really quite simple:
On an 8051, the so-called "vector table" contains the (start of) the actual service routine; When an interrupt occurs, the 8051 executes the instruction that it finds in the appropriate vector table entry.
On an ARM (and many other architectures; including x86), the vector table contains the start address of the service routine; When an interrupt occurs, the ARM fetches the address that it finds in the appropriate vector table entry, and then executes the instruction located at that address.
"where can we see the vector table in actual code"
Again, the ARM Vector table is not "actual code"; it is just a list of addresses - and (apart from the 1st entry) each of those addresses is the start address of the handler.
"How can we register some function in Vector table"
In 'C', the name of a function gives its address.
"Appreciate some more document if you can suggest for reference"
It is such a fundamental part of operation of any embedded system that any examples will have to have a Vector Table!
Have you looked at the examples that Keil provide?
Have you looked at the examples that the chip manufacturer provides?
Book list available here: http://www.keil.com/books/
Some training providers, seminars, etc, listed here: http://www.keil.com/events/ http://www.keil.com/events/links.asp http://www.keil.com/events/classlist.asp http://www.keil.com/events/seminarlist.asp