Commit db1e649575a741527ca0fd7815515c2f97924410 | zig

author	mihael <hi@mihaelm.com> 2026-03-18 23:20:46+01:00
committer	mihael <hi@mihaelm.com> 2026-04-02 23:54:19+02:00
log	db1e649575a741527ca0fd7815515c2f97924410
tree	c72f39e4b7cb178fc80bf1b67d6eb7f4f4c90787
parent	521a093334eb92b4fd2430b9018ed94b912857a8
signature	Signed by SSH key SHA256:aoFoShdYLdrqMichqKXSSieTKUfACUIDJHsKc4V2tQg

`libzigc/math`: Implement `frexpl`

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=frexpl -fqemu -fwasmtime --summary line
Build Summary: 369/369 steps succeeded
```

6 files changed, 5 insertions(+), 103 deletions(-)

lib
- c
  - math.zig
- libc
  - mingw
    math
    frexpl.c
  - musl
    src
    math
    frexpl.c
src
- libs

lib/c/math.zig+5

...	...	@@ -37,6 +37,7 @@ comptime {
37	37	if (builtin.target.isMinGW() or builtin.target.isMuslLibC() or builtin.target.isWasiLibC()) {
38	38	symbol(&coshf, "coshf");
39	39	symbol(&frexpf, "frexpf");
	40	symbol(&frexpl, "frexpl");
40	41	symbol(&hypotf, "hypotf");
41	42	symbol(&hypotl, "hypotl");
42	43	symbol(&modff, "modff");
...	...	@@ -190,6 +191,10 @@ fn frexpf(x: f32, e: *c_int) callconv(.c) f32 {
190	191	return frexpGeneric(f32, x, e);
191	192	}
192	193
	194	fn frexpl(x: c_longdouble, e: *c_int) callconv(.c) c_longdouble {
	195	return frexpGeneric(c_longdouble, x, e);
	196	}
	197
193	198	fn hypot(x: f64, y: f64) callconv(.c) f64 {
194	199	return math.hypot(x, y);
195	200	}

lib/libc/mingw/math/frexpl.c deleted-71

...	...	@@ -1,71 +0,0 @@
1		/**
2		* This file has no copyright assigned and is placed in the Public Domain.
3		* This file is part of the mingw-w64 runtime package.
4		* No warranty is given; refer to the file DISCLAIMER.PD within this package.
5		*/
6		long double frexpl(long double value, int* exp);
7
8		#if __SIZEOF_LONG_DOUBLE__ == __SIZEOF_DOUBLE__
9
10		double frexp(double value, int* exp);
11
12		/* On ARM `long double` is 64 bits. */
13		long double frexpl(long double value, int* exp)
14		{
15		return frexp(value, exp);
16		}
17
18		#elif defined(_AMD64_) \|\| defined(__x86_64__) \|\| defined(_X86_) \|\| defined(__i386__)
19
20		#include <stdint.h>
21
22		/* https://en.wikipedia.org/wiki/Extended_precision#x86_extended_precision_format */
23		typedef union x87reg_ {
24		struct __attribute__((__packed__)) {
25		uint64_t f64;
26		uint16_t exp : 15;
27		uint16_t sgn : 1;
28		};
29		long double f;
30		} x87reg;
31
32		long double frexpl(long double value, int* exp)
33		{
34		int n;
35		x87reg reg;
36		reg.f = value;
37		if(reg.exp == 0x7FFF) {
38		/* The value is an infinity or NaN.
39		* Store zero in `exp`. Return the value as is. /
40		*exp = 0;
41		return reg.f;
42		}
43		if(reg.exp != 0) {
44		/* The value is normalized.
45		* Extract and zero out the exponent. */
46		*exp = reg.exp - 0x3FFE;
47		reg.exp = 0x3FFE;
48		return reg.f;
49		}
50		if(reg.f64 == 0) {
51		/* The value is zero.
52		* Store zero in `*exp`. Return the value as is.
53		* Note the signness. */
54		*exp = 0;
55		return reg.f;
56		}
57		/* The value is denormalized.
58		* Extract the exponent, normalize the value, then zero out
59		* the exponent. Note that x87 uses an explicit leading bit. */
60		n = __builtin_clzll(reg.f64);
61		reg.f64 <<= n;
62		*exp = 1 - 0x3FFE - n;
63		reg.exp = 0x3FFE;
64		return reg.f;
65		}
66
67		#else
68
69		#error Please add `frexpl()` implementation for this platform.
70
71		#endif

lib/libc/musl/src/math/frexpl.c deleted-29

...	...	@@ -1,29 +0,0 @@
1		#include "libm.h"
2
3		#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
4		long double frexpl(long double x, int *e)
5		{
6		return frexp(x, e);
7		}
8		#elif (LDBL_MANT_DIG == 64 \|\| LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
9		long double frexpl(long double x, int *e)
10		{
11		union ldshape u = {x};
12		int ee = u.i.se & 0x7fff;
13
14		if (!ee) {
15		if (x) {
16		x = frexpl(x*0x1p120, e);
17		*e -= 120;
18		} else *e = 0;
19		return x;
20		} else if (ee == 0x7fff) {
21		return x;
22		}
23
24		*e = ee - 0x3ffe;
25		u.i.se &= 0x8000;
26		u.i.se \|= 0x3ffe;
27		return u.f;
28		}
29		#endif

src/libs/mingw.zig-1

...	...	@@ -613,7 +613,6 @@ const mingw32_generic_src = [_][]const u8{
613	613	"math" ++ path.sep_str ++ "fpclassify.c",
614	614	"math" ++ path.sep_str ++ "fpclassifyf.c",
615	615	"math" ++ path.sep_str ++ "fpclassifyl.c",
616		"math" ++ path.sep_str ++ "frexpl.c",
617	616	"math" ++ path.sep_str ++ "ldexpf.c",
618	617	"math" ++ path.sep_str ++ "lgamma.c",
619	618	"math" ++ path.sep_str ++ "lgammaf.c",

src/libs/musl.zig-1

...	...	@@ -839,7 +839,6 @@ const src_files = [_][]const u8{
839	839	"musl/src/math/__fpclassify.c",
840	840	"musl/src/math/__fpclassifyf.c",
841	841	"musl/src/math/__fpclassifyl.c",
842		"musl/src/math/frexpl.c",
843	842	"musl/src/math/i386/acosl.s",
844	843	"musl/src/math/i386/asinf.s",
845	844	"musl/src/math/i386/asinl.s",

src/libs/wasi_libc.zig-1

...	...	@@ -701,7 +701,6 @@ const libc_top_half_src_files = [_][]const u8{
701	701	"musl/src/math/finitef.c",
702	702	"musl/src/math/fma.c",
703	703	"musl/src/math/fmaf.c",
704		"musl/src/math/frexpl.c",
705	704	"musl/src/math/ilogb.c",
706	705	"musl/src/math/ilogbf.c",
707	706	"musl/src/math/ilogbl.c",