Re: [OT] On `ad hominem' - OS X users

Sherm Pendley wrote:
It's a fact that modern compilers *usually* generate faster code than
hand-coded assembler. If this library is an exception to that general
rule, why can't you just say so without being a condescending ass
about it?

While this is true, it applies only to things that the language can express. Most processors have special tricks for multi-word arithmetic (such as the Intel ADC instruction or the new z/Architecture ALC family of instructions) that cannot be expressed at all in, say, C. (That is, C has no way of saying, "Add X to Y, and add an additional 1 if the last addition set the CPU carry flag.")

Similarly, a language that cannot express fixed-point decimal arithmetic cannot generate z/Architecture packed-decimal instructions, and a language that does not incorporate something comparable to COBOL PICTURE clauses cannot generate z/Architecture ED or EDMK instructions. And, while modern architectures have special instructions to test and set lightweight semaphores, C has no way of using them.

(Sometimes, it's the other way around. z/Architecture has a special instruction just to implement C strcpy.)

--
John W. Kennedy
"I want everybody to be smart. As smart as they can be. A world of ignorant people is too dangerous to live in."
-- Garson Kanin. "Born Yesterday"
.

Relevant Pages

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