Thread: Turbo C

I think alot of C developers like to speed up their code by using ASM

I'd have to disagree with this. It's been a seriously long time since I had to do this. Mind you, I still look at the ASM the compiler generates, just to make sure it's generating the code I expect.

Writing ASM is very much the last resort when it comes to speeding up your code - there are so many other things you can do before you have to do this.

It is also very hard to do - especially on modern processors with multiple stage pipelines, and in some cases multiple execution units. Being able to program for such processors to their best advantage will take a lot of effort (non-portable learning effort I might add).

http://www.ontek.com/mikey/optimization.html

The only real reason for using ASM is as Witch_King says, writing operating systems, where the compiler cannot generate the instructions you require. These typically being the supervisor level instructions for managing cache, memory management units and so on.

you can use asm to optomize speed critical parts of teh program. Doesn't it also allow (restricted) access to the hardware?

You should learn how to work with your operating system, not against it. There are so many details to win32 API without getting into assembly programming, that you can use to speed up your programs critical paths. Try working with individual processes, look up threading. But getting any more specific limits the compatibility of the program and can be a danger to the complex and efficiently designed professional operating system. If anything, next gerneration operating systems are even more complex and powerful, they allow the programmer to write more secure programs, to have more control over libraries and to protect programs from each other, especially programs that share assemblies.

I love learning about ASM. It gives you sort of an intimate knowledge of the processor. althought Salem is right when he says that modern processors with the added segments/pipelines/etc. are hard to work with. Although, the only use I've ever found for it is using it to speed up character output. Other than that...I dunno. Maybe speeding up renering time in a program or something.