Re: Fastest way to zero a slice of memory
On Sunday, 4 March 2018 at 15:23:41 UTC, Nordlöw wrote: When zeroing a slice of memory (either stack or heap) such as enum n = 100; ubyte[n] chunk; should I use `memset` such as memset(chunk.ptr, 0, n/2); // zero first half or an array assignment such as chunk[0 .. n/2] = 0; // zero first half or are they equivalent in release mode? Further, does it depend on whether the slice length is known at compile-time or not? I'd recommend not concerning yourself with such low-level optimizations and let the compiler do that for you, and only jump in yourself if profiling/benchmarking shows that there's a bottleneck, and prefer nice readable code otherwise. E.g., LDC will lower `chunk[0 .. n/2] = 0` to a memset() call if the length is unknown at compile-time, and otherwise replace it with good-looking assembly code (xor vector register and store it consecutively to memory): https://run.dlang.io/is/I6Fq9G (click on ASM and check the assembly for the two functions).
Re: Fastest way to zero a slice of memory
On Sunday, 4 March 2018 at 15:23:41 UTC, Nordlöw wrote: When zeroing a slice of memory (either stack or heap) such as enum n = 100; ubyte[n] chunk; should I use `memset` such as memset(chunk.ptr, 0, n/2); // zero first half or an array assignment such as chunk[0 .. n/2] = 0; // zero first half or are they equivalent in release mode? Further, does it depend on whether the slice length is known at compile-time or not? This is worth reading: https://stackoverflow.com/questions/3654905/faster-way-to-zero-memory-than-with-memset
Fastest way to zero a slice of memory
When zeroing a slice of memory (either stack or heap) such as enum n = 100; ubyte[n] chunk; should I use `memset` such as memset(chunk.ptr, 0, n/2); // zero first half or an array assignment such as chunk[0 .. n/2] = 0; // zero first half or are they equivalent in release mode? Further, does it depend on whether the slice length is known at compile-time or not?
