`nextAfter()` returns the next representable value after `x` in the direction of `y` and is a standard math library function ([C++](https://en.cppreference.com/w/cpp/numeric/math/nextafter), [Java](https://docs.oracle.com/javase/8/docs/api/java/lang/Math.html#nextAfter-double-double-)). It is primarily useful for bitwise incrementing/decrementing floats.
This implementation supports runtime integers, runtime floats and `comptime_int`. `comptime_float` is not supported because NaNs/infinities are intentionally difficult to obtain and because I'm not sure if the fact that it's backed by `f128` is supposed to be an implementation detail. Either way, the user could just call the function with the floating-point type whose behavior they want at comptime and then cast the result to `comptime_float`.
The float implementation was ported from mingw-w64 with some slight changes made possible because the Zig standard library doesn't care about raising FP exceptions.
The number of test cases may seem excessive but they should cover every normal and edge case for every float type and are especially important for verifying that `f80` works.
* Generalise NaN handling and make std.math.nan() give quiet NaNs
* Address uses of std.math.qnan_* and std.math.nan_* consts
* Comment out failing test due to issues with signalling NaN
* Fix issue in c_builtins.zig where we need qnan_u32
All of the std except these few functions call it "eql" instead of "eq".
This has previously tripped me up when I expected the equality check function to be called "eql"
(just like all the rest of the std) instead of "eq".
The motivation is consistency.
If search "eq" on Autodoc, these functions stick out and it looks inconsistent.
I just noticed there are also a few functions spelling it out as "equal" (such as std.mem.allEqual).
Maybe those functions should also spell it "eql" but that can be done in a future PR.
Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
- `bytes` -> `buffer`
- Correct naming consistency between
1. fn argument and doc comment of `(read|write)PackedTwosComplement`
2. fn arguments of `(read|write)PackedTwosComplement` and `(read|write)TwosComplement`
The majority of these are in comments, some in doc comments which might
affect the generated documentation, and a few in parameter names -
nothing that should be breaking, however.
Now they use slices or array pointers with any element type instead of
requiring byte pointers.
This is a breaking enhancement to the language.
The safety check for overlapping pointers will be implemented in a
future commit.
closes#14040
Tests that only reference decls for the purpose of analyzing more tests
should be unnamed, otherwise trying to filter for just a referenced test
can become impossible depending on the names.
When a big.Int.Mutable had more than two limbs, it was possible for
this function to change the `len` field without zeroing limbs in the
active range. These uninitialized limbs would then be used in
`truncate()` and could cause invalid results.
Closes#13571
This pull request removes the optional allocator argument from functions
`divFloor` and `divTrunc`. As a result, the comments related to accepting an
optional `allocator` are no longer applicable. The support for accepting
an optional allocator was removed in #10017.
Underlying fix should have been d7b029995c.
u128 limb sizes are still not fully tested as we are missing compiler-rt
support (__divei4, __modei4 on x86_64). Should be no zig blockers so the
assertion has been removed.
- Fix zig_clz_u128 not respecting the bits argument. This was crashing the compile-rt addxf3 tests with the cbe
- Instead of redering a negation for negative 128 bit int literals, render the literal as twos complement. This allows
rendering int representations of floats correctly (specifically f80).
* Export invalidFmtErr
To allow consistent use of "invalid format string" compile error
response for badly formatted format strings.
See https://github.com/ziglang/zig/pull/13489#issuecomment-1311759340.
* Replace format compile errors with invalidFmtErr
- Provides more consistent compile errors.
- Gives user info about the type of the badly formated value.
* Rename invalidFmtErr as invalidFmtError
For consistency. Zig seems to use “Error” more often than “Err”.
* std: add invalid format string checks to remaining custom formatters
* pass reference-trace to comp when building build file; fix checkobjectstep
Packed memory has a well-defined layout that doesn't require
conversion from an integer to read from. Let's use it :-)
This change means that for bitcasting to/from a packed value that
is N layers deep, we no longer have to create N temporary big-ints
and perform N copies.
Other miscellaneous improvements:
- Adds support for casting to packed enums and vectors
- Fixes bitcasting to/from vectors outside of a packed struct
- Adds a fast path for bitcasting <= u/i64
- Fixes bug when bitcasting f80 which would clear following fields
This also changes the bitcast memory layout of exotic integers on
big-endian systems to match what's empirically observed on our targets.
Technically, this layout is not guaranteed by LLVM so we should probably
ban bitcasts that reveal these padding bits, but for now this is an
improvement.
