Commit f36d0573cd0f80b271b9f07a7215fa237d14ae9a | zig

author	kineye <27766253+JanikkinaJ@users.noreply.github.com.> 2026-02-07 16:09:29+01:00
committer	Andrew Kelley <andrew@ziglang.org> 2026-02-12 21:42:38-08:00
log	f36d0573cd0f80b271b9f07a7215fa237d14ae9a
tree	2075d0d2e778248953a853c5a6dd352724e78a6e
parent	5132d78e8385cbadc888275761258a1fca27b6f0

zig libc: add rint

4 files changed, 57 insertions(+), 47 deletions(-)

lib
- c
  - math.zig
- libc
  - musl
    src
    math
    rint.c
    s390x
    rint.c
src
- libs
  - musl.zig

lib/c/math.zig+57

...	...	@@ -56,6 +56,7 @@ comptime {
56	56	if (builtin.target.isMuslLibC()) {
57	57	symbol(&copysignf, "copysignf");
58	58	symbol(&copysign, "copysign");
	59	symbol(&rint, "rint");
59	60	}
60	61	symbol(&copysignl, "copysignl");
61	62	}
...	...	@@ -158,3 +159,59 @@ fn pow10(x: f64) callconv(.c) f64 {
158	159	fn pow10f(x: f32) callconv(.c) f32 {
159	160	return exp10f(x);
160	161	}
	162
	163	fn rint(x: f64) callconv(.c) f64 {
	164	const toint: f64 = 1.0 / @as(f64, std.math.floatEps(f64));
	165	const a: u64 = @bitCast(x);
	166	const e = a >> 52 & 0x7ff;
	167	const s = a >> 63;
	168	var y: f64 = undefined;
	169
	170	if (e >= 0x3ff + 52) {
	171	return x;
	172	}
	173	if (s == 1) {
	174	y = x - toint + toint;
	175	} else {
	176	y = x + toint - toint;
	177	}
	178	if (y == 0) {
	179	return if (s == 1) -0.0 else 0;
	180	}
	181	return y;
	182	}
	183
	184	test "rint" {
	185	// Positive numbers round correctly
	186	try std.testing.expectEqual(@as(f64, 42.0), rint(42.2));
	187	try std.testing.expectEqual(@as(f64, 42.0), rint(41.8));
	188
	189	// Negative numbers round correctly
	190	try std.testing.expectEqual(@as(f64, -6.0), rint(-5.9));
	191	try std.testing.expectEqual(@as(f64, -6.0), rint(-6.1));
	192
	193	// No rounding needed test
	194	try std.testing.expectEqual(@as(f64, 5.0), rint(5.0));
	195	try std.testing.expectEqual(@as(f64, -10.0), rint(-10.0));
	196	try std.testing.expectEqual(@as(f64, 0.0), rint(0.0));
	197
	198	// Very large numbers return unchanged
	199	const large: f64 = 9007199254740992.0; // 2^53
	200	try std.testing.expectEqual(large, rint(large));
	201	try std.testing.expectEqual(-large, rint(-large));
	202
	203	// Small positive numbers round to zero
	204	const pos_result = rint(0.3);
	205	try std.testing.expectEqual(@as(f64, 0.0), pos_result);
	206	try std.testing.expect(@as(u64, @bitCast(pos_result)) == 0);
	207
	208	// Small negative numbers round to negative zero
	209	const neg_result = rint(-0.3);
	210	try std.testing.expectEqual(@as(f64, 0.0), neg_result);
	211	const bits: u64 = @bitCast(neg_result);
	212	try std.testing.expect((bits >> 63) == 1);
	213
	214	// Exact half rounds to nearest even (banker's rounding)
	215	try std.testing.expectEqual(@as(f64, 2.0), rint(2.5));
	216	try std.testing.expectEqual(@as(f64, 4.0), rint(3.5));
	217	}

lib/libc/musl/src/math/rint.c deleted-28

...	...	@@ -1,28 +0,0 @@
1		#include <float.h>
2		#include <math.h>
3		#include <stdint.h>
4
5		#if FLT_EVAL_METHOD==0 \|\| FLT_EVAL_METHOD==1
6		#define EPS DBL_EPSILON
7		#elif FLT_EVAL_METHOD==2
8		#define EPS LDBL_EPSILON
9		#endif
10		static const double_t toint = 1/EPS;
11
12		double rint(double x)
13		{
14		union {double f; uint64_t i;} u = {x};
15		int e = u.i>>52 & 0x7ff;
16		int s = u.i>>63;
17		double_t y;
18
19		if (e >= 0x3ff+52)
20		return x;
21		if (s)
22		y = x - toint + toint;
23		else
24		y = x + toint - toint;
25		if (y == 0)
26		return s ? -0.0 : 0;
27		return y;
28		}

lib/libc/musl/src/math/s390x/rint.c deleted-15

...	...	@@ -1,15 +0,0 @@
1		#include <math.h>
2
3		#if defined(__HTM__) \|\| __ARCH__ >= 9
4
5		double rint(double x)
6		{
7		__asm__ ("fidbr %0, 0, %1" : "=f"(x) : "f"(x));
8		return x;
9		}
10
11		#else
12
13		#include "../rint.c"
14
15		#endif

src/libs/musl.zig-4

...	...	@@ -797,7 +797,6 @@ const src_files = [_][]const u8{
797	797	"musl/src/math/aarch64/lroundf.c",
798	798	"musl/src/math/aarch64/nearbyint.c",
799	799	"musl/src/math/aarch64/nearbyintf.c",
800		"musl/src/math/aarch64/rint.c",
801	800	"musl/src/math/aarch64/rintf.c",
802	801	"musl/src/math/acosf.c",
803	802	"musl/src/math/acosh.c",
...	...	@@ -887,7 +886,6 @@ const src_files = [_][]const u8{
887	886	"musl/src/math/i386/remquof.s",
888	887	"musl/src/math/i386/remquol.s",
889	888	"musl/src/math/i386/remquo.s",
890		"musl/src/math/i386/rint.c",
891	889	"musl/src/math/i386/rintf.c",
892	890	"musl/src/math/i386/rintl.c",
893	891	"musl/src/math/i386/scalblnf.s",
...	...	@@ -981,7 +979,6 @@ const src_files = [_][]const u8{
981	979	"musl/src/math/remquo.c",
982	980	"musl/src/math/remquof.c",
983	981	"musl/src/math/remquol.c",
984		"musl/src/math/rint.c",
985	982	"musl/src/math/rintf.c",
986	983	"musl/src/math/rintl.c",
987	984	"musl/src/math/riscv32/fma.c",
...	...	@@ -993,7 +990,6 @@ const src_files = [_][]const u8{
993	990	"musl/src/math/s390x/nearbyint.c",
994	991	"musl/src/math/s390x/nearbyintf.c",
995	992	"musl/src/math/s390x/nearbyintl.c",
996		"musl/src/math/s390x/rint.c",
997	993	"musl/src/math/s390x/rintf.c",
998	994	"musl/src/math/s390x/rintl.c",
999	995	"musl/src/math/scalb.c",