Commit 1f92162875a3f05942dad6696b206cb9a1394f80 | zig

author	mihael <hi@mihaelm.com> 2026-03-09 23:17:46+01:00
committer	mihael <hi@mihaelm.com> 2026-03-10 00:42:14+01:00
log	1f92162875a3f05942dad6696b206cb9a1394f80
tree	331e363f84c6a6146587f478cf6e2e5b29512da7
parent	3b515fbede945a2927d5aba59212553a8b26b944
signature	Signed by SSH key SHA256:aoFoShdYLdrqMichqKXSSieTKUfACUIDJHsKc4V2tQg

Reimplement `cosh` in `libzigc`

The function basically calls the Zig std's implementation.
The changes were tested by running:

```
$ ./build/stage3/bin/zig build -p stage4 -Denable-llvm -Dno-lib

$ stage4/bin/zig build test-libc -Dlibc-test-path=<LIBC-TEST-PATH> -Dtest-filter=cosh -fqemu -fwasmtime --summary line
Build Summary: 921/921 steps succeeded
```

5 files changed, 5 insertions(+), 86 deletions(-)

lib
- c
  - math.zig
- libc
  - musl
    src
    math
    cosh.c
  - wasi
    libc-top-half
    musl
    src
    math
    cosh.c
src
- libs
  - musl.zig
  - wasi_libc.zig

lib/c/math.zig+5

...	...	@@ -45,6 +45,7 @@ comptime {
45	45	symbol(&atanl, "atanl");
46	46	symbol(&cbrt, "cbrt");
47	47	symbol(&cbrtf, "cbrtf");
	48	symbol(&cosh, "cosh");
48	49	symbol(&exp10, "exp10");
49	50	symbol(&exp10f, "exp10f");
50	51	symbol(&hypot, "hypot");
...	...	@@ -125,6 +126,10 @@ fn copysignl(x: c_longdouble, y: c_longdouble) callconv(.c) c_longdouble {
125	126	return math.copysign(x, y);
126	127	}
127	128
	129	fn cosh(x: f64) callconv(.c) f64 {
	130	return math.cosh(x);
	131	}
	132
128	133	fn cbrt(x: f64) callconv(.c) f64 {
129	134	return math.cbrt(x);
130	135	}

lib/libc/musl/src/math/cosh.c deleted-40

...	...	@@ -1,40 +0,0 @@
1		#include "libm.h"
2
3		/* cosh(x) = (exp(x) + 1/exp(x))/2
4		* = 1 + 0.5(exp(x)-1)(exp(x)-1)/exp(x)
5		* = 1 + x*x/2 + o(x^4)
6		*/
7		double cosh(double x)
8		{
9		union {double f; uint64_t i;} u = {.f = x};
10		uint32_t w;
11		double t;
12
13		/* \|x\| */
14		u.i &= (uint64_t)-1/2;
15		x = u.f;
16		w = u.i >> 32;
17
18		/* \|x\| < log(2) */
19		if (w < 0x3fe62e42) {
20		if (w < 0x3ff00000 - (26<<20)) {
21		/* raise inexact if x!=0 */
22		FORCE_EVAL(x + 0x1p120f);
23		return 1;
24		}
25		t = expm1(x);
26		return 1 + tt/(2(1+t));
27		}
28
29		/* \|x\| < log(DBL_MAX) */
30		if (w < 0x40862e42) {
31		t = exp(x);
32		/* note: if x>log(0x1p26) then the 1/t is not needed */
33		return 0.5*(t + 1/t);
34		}
35
36		/* \|x\| > log(DBL_MAX) or nan */
37		/* note: the result is stored to handle overflow */
38		t = __expo2(x, 1.0);
39		return t;
40		}

lib/libc/wasi/libc-top-half/musl/src/math/cosh.c deleted-44

...	...	@@ -1,44 +0,0 @@
1		#include "libm.h"
2
3		/* cosh(x) = (exp(x) + 1/exp(x))/2
4		* = 1 + 0.5(exp(x)-1)(exp(x)-1)/exp(x)
5		* = 1 + x*x/2 + o(x^4)
6		*/
7		double cosh(double x)
8		{
9		union {double f; uint64_t i;} u = {.f = x};
10		uint32_t w;
11		double t;
12
13		/* \|x\| */
14		u.i &= (uint64_t)-1/2;
15		x = u.f;
16		w = u.i >> 32;
17
18		/* \|x\| < log(2) */
19		if (w < 0x3fe62e42) {
20		if (w < 0x3ff00000 - (26<<20)) {
21		/* raise inexact if x!=0 */
22		FORCE_EVAL(x + 0x1p120f);
23		return 1;
24		}
25		t = expm1(x);
26		return 1 + tt/(2(1+t));
27		}
28
29		/* \|x\| < log(DBL_MAX) */
30		if (w < 0x40862e42) {
31		t = exp(x);
32		/* note: if x>log(0x1p26) then the 1/t is not needed */
33		return 0.5*(t + 1/t);
34		}
35
36		/* \|x\| > log(DBL_MAX) or nan */
37		/* note: the result is stored to handle overflow */
38		#ifdef __wasilibc_unmodified_upstream // Wasm doesn't have alternate rounding modes
39		t = __expo2(x, 1.0);
40		#else
41		t = __expo2(x);
42		#endif
43		return t;
44		}

src/libs/musl.zig-1

...	...	@@ -819,7 +819,6 @@ const src_files = [_][]const u8{
819	819	"musl/src/math/cbrtl.c",
820	820	"musl/src/math/__cos.c",
821	821	"musl/src/math/__cosdf.c",
822		"musl/src/math/cosh.c",
823	822	"musl/src/math/coshf.c",
824	823	"musl/src/math/coshl.c",
825	824	"musl/src/math/__cosl.c",

src/libs/wasi_libc.zig-1

...	...	@@ -1003,7 +1003,6 @@ const libc_top_half_src_files = [_][]const u8{
1003	1003	"wasi/libc-top-half/musl/src/locale/locale_map.c",
1004	1004	"wasi/libc-top-half/musl/src/locale/newlocale.c",
1005	1005	"wasi/libc-top-half/musl/src/locale/uselocale.c",
1006		"wasi/libc-top-half/musl/src/math/cosh.c",
1007	1006	"wasi/libc-top-half/musl/src/math/coshf.c",
1008	1007	"wasi/libc-top-half/musl/src/math/__expo2.c",
1009	1008	"wasi/libc-top-half/musl/src/math/__expo2f.c",