High-level Languages and Speed

nitsudima writes to tell us Informit's David Chisnall takes a look at the 'myth' of high-level languages versus speed and why it might not be entirely accurate. From the article: "When C was created, it was very fast because it was almost trivial to turn C code into equivalent machine code. But this was only a short-term benefit; in the 30 years since C was created, processors have changed a lot. The task of mapping C code to a modern microprocessor has gradually become increasingly difficult. Since a lot of legacy C code is still around, however, a huge amount of research effort (and money) has been applied to the problem, so we still can get good performance from the language."

Comments

Imaginary history

[dpbsmith]

Whoa! This article seems to be making up history out of whole cloth. I'm not even sure where to begin. It's just totally out to lunch.

C was not a reaction to LISP. I can't even imagine why anyone would say this. LISP's if/then/else was an influence on ALGOL and later languages.

C might have been a reaction to Pascal, which in turn was a reaction to ALGOL.

LISP was not "the archetypal high-level language." The very names CAR and CDR mean "contents of address register" and "contents of decrement register," direct references to hardware registers on the IBM 704. When the names of fundamental languages constructs are those of specific registers in a specific processor, that is not a "high-level language" at all. Later efforts to build machines with machine architectures optimized for implementation of LISP further show that LISP was not considered "a high-level language."

C was not specifically patterned on the PDP-11. Rather, both of them were based on common practice and understanding of what was in the air at the time. C was a direct successor to, and reasonably similar to BCPL, on Honeywell 635 and 645, the IBM 360, the TX-2, the CDC 6400, the Univac 1108, the PDP-9, the KDF 9 and the Atlas 2.

C makes an interesting comparison with Pascal; you can see that C is, in many ways, a computer language rather than a mathematical language. For example, the inclusion of specific constructs for increment and decrement (as opposed to just writing A := A + 1) puts it closer, not to PDP-11 architecture, but to contemporary machine architecture in general.