Add more math functions (#128)

2025-05-22 21:32:31 +00:00 · 2021-03-17 20:05:12 -07:00 · 2021-03-17 20:05:12 -07:00 · 8a236433a2
commit 8a236433a2
parent ab64ef7364
13 changed files with 1249 additions and 0 deletions
--- a/libc/tinymath/remquo.c
+++ b/libc/tinymath/remquo.c
@ -0,0 +1,116 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╚──────────────────────────────────────────────────────────────────────────────╝
+│                                                                              │
+│  Musl Libc                                                                   │
+│  Copyright © 2005-2020 Rich Felker, et al.                                   │
+│                                                                              │
+│  Permission is hereby granted, free of charge, to any person obtaining       │
+│  a copy of this software and associated documentation files (the             │
+│  "Software"), to deal in the Software without restriction, including         │
+│  without limitation the rights to use, copy, modify, merge, publish,         │
+│  distribute, sublicense, and/or sell copies of the Software, and to          │
+│  permit persons to whom the Software is furnished to do so, subject to       │
+│  the following conditions:                                                   │
+│                                                                              │
+│  The above copyright notice and this permission notice shall be              │
+│  included in all copies or substantial portions of the Software.             │
+│                                                                              │
+│  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,             │
+│  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF          │
+│  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.      │
+│  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY        │
+│  CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,        │
+│  TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE           │
+│  SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                      │
+│                                                                              │
+╚─────────────────────────────────────────────────────────────────────────────*/
+
+#include "libc/math.h"
+
+asm(".ident\t\"\\n\\n\
+Musl libc (MIT License)\\n\
+Copyright 2005-2020 Rich Felker, et. al.\"");
+asm(".include \"libc/disclaimer.inc\"");
+
+/* clang-format off */
+
+double remquo(double x, double y, int *quo)
+{
+	union {double f; uint64_t i;} ux = {x}, uy = {y};
+	int ex = ux.i>>52 & 0x7ff;
+	int ey = uy.i>>52 & 0x7ff;
+	int sx = ux.i>>63;
+	int sy = uy.i>>63;
+	uint32_t q;
+	uint64_t i;
+	uint64_t uxi = ux.i;
+
+	*quo = 0;
+	if (uy.i<<1 == 0 || isnan(y) || ex == 0x7ff)
+		return (x*y)/(x*y);
+	if (ux.i<<1 == 0)
+		return x;
+
+	/* normalize x and y */
+	if (!ex) {
+		for (i = uxi<<12; i>>63 == 0; ex--, i <<= 1);
+		uxi <<= -ex + 1;
+	} else {
+		uxi &= -1ULL >> 12;
+		uxi |= 1ULL << 52;
+	}
+	if (!ey) {
+		for (i = uy.i<<12; i>>63 == 0; ey--, i <<= 1);
+		uy.i <<= -ey + 1;
+	} else {
+		uy.i &= -1ULL >> 12;
+		uy.i |= 1ULL << 52;
+	}
+
+	q = 0;
+	if (ex < ey) {
+		if (ex+1 == ey)
+			goto end;
+		return x;
+	}
+
+	/* x mod y */
+	for (; ex > ey; ex--) {
+		i = uxi - uy.i;
+		if (i >> 63 == 0) {
+			uxi = i;
+			q++;
+		}
+		uxi <<= 1;
+		q <<= 1;
+	}
+	i = uxi - uy.i;
+	if (i >> 63 == 0) {
+		uxi = i;
+		q++;
+	}
+	if (uxi == 0)
+		ex = -60;
+	else
+		for (; uxi>>52 == 0; uxi <<= 1, ex--);
+end:
+	/* scale result and decide between |x| and |x|-|y| */
+	if (ex > 0) {
+		uxi -= 1ULL << 52;
+		uxi |= (uint64_t)ex << 52;
+	} else {
+		uxi >>= -ex + 1;
+	}
+	ux.i = uxi;
+	x = ux.f;
+	if (sy)
+		y = -y;
+	if (ex == ey || (ex+1 == ey && (2*x > y || (2*x == y && q%2)))) {
+		x -= y;
+		q++;
+	}
+	q &= 0x7fffffff;
+	*quo = sx^sy ? -(int)q : (int)q;
+	return sx ? -x : x;
+}