* add `@bswap` builtin function. See #767
* comptime evaluation facilities are improved to be able to
handle a `@ptrCast` with a backing array.
* `@truncate` allows "truncating" a u0 value to any integer
type, and the result is always comptime known to be `0`.
* when specifying pointer alignment in a type expression,
the alignment value of pointers which do not have addresses
at runtime is ignored, and always has the default/ABI alignment
* threw in a fix to freebsd/x86_64.zig to update syntax from
language changes
* some improvements are pending #863closes#638closes#1733
std lib API changes
* io.InStream().readIntNe renamed to readIntNative
* io.InStream().readIntLe renamed to readIntLittle
* io.InStream().readIntBe renamed to readIntBig
* introduced io.InStream().readIntForeign
* io.InStream().readInt has parameter order changed
* io.InStream().readVarInt has parameter order changed
* io.InStream().writeIntNe renamed to writeIntNative
* introduced io.InStream().writeIntForeign
* io.InStream().writeIntLe renamed to writeIntLittle
* io.InStream().writeIntBe renamed to writeIntBig
* io.InStream().writeInt has parameter order changed
* mem.readInt has different parameters and semantics
* introduced mem.readIntNative
* introduced mem.readIntForeign
* mem.readIntBE renamed to mem.readIntBig and different API
* mem.readIntLE renamed to mem.readIntLittle and different API
* introduced mem.readIntSliceNative
* introduced mem.readIntSliceForeign
* introduced mem.readIntSliceLittle
* introduced mem.readIntSliceBig
* introduced mem.readIntSlice
* mem.writeInt has different parameters and semantics
* introduced mem.writeIntNative
* introduced mem.writeIntForeign
* mem.writeIntBE renamed to mem.readIntBig and different semantics
* mem.writeIntLE renamed to mem.readIntLittle and different semantics
* introduced mem.writeIntSliceForeign
* introduced mem.writeIntSliceNative
* introduced mem.writeIntSliceBig
* introduced mem.writeIntSliceLittle
* introduced mem.writeIntSlice
* removed mem.endianSwapIfLe
* removed mem.endianSwapIfBe
* removed mem.endianSwapIf
* added mem.littleToNative
* added mem.bigToNative
* added mem.toNative
* added mem.nativeTo
* added mem.nativeToLittle
* added mem.nativeToBig
The main changes are:
Unrolling the inner rounds of salsa20_wordtobyte which doubles the speed.
Passing the slice explicitly instead of returning the array saves a copy (can optimize out in future with copy elision) and gives ~10% improvement.
Inlining the outer loop gives ~15-20% improvement but it costs an extra 4Kb of code space. I think the tradeoff is worthwhile here.
The other inline loops are small and can be done by the compiler if it is worthwhile.
The rotate function replacement doesn't alter the performance from the former.
The modified throughput test I've used to benchmark is as follows. Interestingly we need to allocate memory instead of using a fixed buffer else Zig optimizes the whole thing out.
https://github.com/ziglang/zig/pull/1369#issuecomment-416456628