sjc@mips.UUCP (03/28/87)
Even if a language had null-terminated strings built in, I don't think a compiler would necessarily have trouble finding opportunities to emit the AMD string-processing instruction. In C, it's even easier, because you just hand-code the str* subroutines. But most languages don't have null-terminated strings. Pascal provides fixed-length strings, which imply heavy use of memcpy and memcmp (or bcopy and bcmp, or equivalent in-line code) rather than the str* family. Similarly, F77 provides fixed-length (or parameterized-length) strings with blank-padding, which implies heavy use of memset as well as memcpy and memcmp. PL/I is similar. I happen to have a profile of a PL/I compiler written in PL/I showing 3.9% of its cycles spent in memcpy, 2.7% in memset, 1.4% in memcmp, and virtually none in the str* family. Ironically, these languages probably need help with string manipulation more than C does, because they encourage or hide inefficient practices. Pascal programmers, for example, often copy or blank-pad strings solely to circumvent type-compatibility problems, and PL/I programs frequently require the compiler to make temporary copies of strings unnecessarily, just because it can't determine statically what the user is going to do with them. -- ...decwrl!mips!sjc Steve Correll
robison@uiucdcsb.UUCP (03/30/87)
Re: "cortic", "quartic" Its CORDIC. I forget what it stands for, but its a uniform way of computing algebraic and transcendental functions. If I remember correctly, the only special support required is a multiple-bit shifter (e.g. a barrel shifter) big enough to handle the mantissa. - Arch