Is it this optiboot -> https://code.google.com/p/optiboot
Yep.
If yes, then this is a good example of asm program in c syntax.
I won't disagree. It's a big case statement (except that if/else turns out to be slightly smaller) that implements a bunch of rather simple commands, so it wouldn't benefit a lot from the use of C "features." In fact, one advantage of coding it in real ASM might have been the ability to make the source layout more modularly grouped in spite of having nearly exactly the same structure.
just for fun, take a look inside boot.h
(which contains a bunch of inline assembler for implementing various pieces of "self-programming" functionality.) Yep; exactly the sort of thing you need assembler for. Note that most of this is not used at all by the bootloader, and all of it is a slightly-modified version of a file from avr-libc that is normally provided with the compiler. There are several other strategic bits of inline assembler that I think are reasonable examples of cases where (inline) assembler makes sense.
All of which has little to do with the point I was making that being coded in C did NOT automatically cause 100+ bytes of startup code to get included. Or any other overhead, for that matter.
(BTW, I made a significant effort to see if I could hit the next-smaller bootloader size (256 bytes) by recoding the C in careful assembler. I pretty-much convinced myself that it's not possible. I MIGHT get a 256byte serial bootloader if I simplified the protocol, but that's a different solution.)