From bd5969fc876a10b18613302db7087ef3c40f18e1 Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@osmora.org>
Date: Thu, 7 Mar 2024 17:28:00 -0500
Subject: lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>
---
 lib/mlibc/options/ansi/musl-generic-math/remquol.c | 124 +++++++++++++++++++++
 1 file changed, 124 insertions(+)
 create mode 100644 lib/mlibc/options/ansi/musl-generic-math/remquol.c

(limited to 'lib/mlibc/options/ansi/musl-generic-math/remquol.c')

diff --git a/lib/mlibc/options/ansi/musl-generic-math/remquol.c b/lib/mlibc/options/ansi/musl-generic-math/remquol.c
new file mode 100644
index 0000000..9b065c0
--- /dev/null
+++ b/lib/mlibc/options/ansi/musl-generic-math/remquol.c
@@ -0,0 +1,124 @@
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double remquol(long double x, long double y, int *quo)
+{
+	return remquo(x, y, quo);
+}
+#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
+long double remquol(long double x, long double y, int *quo)
+{
+	union ldshape ux = {x}, uy = {y};
+	int ex = ux.i.se & 0x7fff;
+	int ey = uy.i.se & 0x7fff;
+	int sx = ux.i.se >> 15;
+	int sy = uy.i.se >> 15;
+	uint32_t q;
+
+	*quo = 0;
+	if (y == 0 || isnan(y) || ex == 0x7fff)
+		return (x*y)/(x*y);
+	if (x == 0)
+		return x;
+
+	/* normalize x and y */
+	if (!ex) {
+		ux.i.se = ex;
+		ux.f *= 0x1p120f;
+		ex = ux.i.se - 120;
+	}
+	if (!ey) {
+		uy.i.se = ey;
+		uy.f *= 0x1p120f;
+		ey = uy.i.se - 120;
+	}
+
+	q = 0;
+	if (ex >= ey) {
+		/* x mod y */
+#if LDBL_MANT_DIG == 64
+		uint64_t i, mx, my;
+		mx = ux.i.m;
+		my = uy.i.m;
+		for (; ex > ey; ex--) {
+			i = mx - my;
+			if (mx >= my) {
+				mx = 2*i;
+				q++;
+				q <<= 1;
+			} else if (2*mx < mx) {
+				mx = 2*mx - my;
+				q <<= 1;
+				q++;
+			} else {
+				mx = 2*mx;
+				q <<= 1;
+			}
+		}
+		i = mx - my;
+		if (mx >= my) {
+			mx = i;
+			q++;
+		}
+		if (mx == 0)
+			ex = -120;
+		else
+			for (; mx >> 63 == 0; mx *= 2, ex--);
+		ux.i.m = mx;
+#elif LDBL_MANT_DIG == 113
+		uint64_t hi, lo, xhi, xlo, yhi, ylo;
+		xhi = (ux.i2.hi & -1ULL>>16) | 1ULL<<48;
+		yhi = (uy.i2.hi & -1ULL>>16) | 1ULL<<48;
+		xlo = ux.i2.lo;
+		ylo = ux.i2.lo;
+		for (; ex > ey; ex--) {
+			hi = xhi - yhi;
+			lo = xlo - ylo;
+			if (xlo < ylo)
+				hi -= 1;
+			if (hi >> 63 == 0) {
+				xhi = 2*hi + (lo>>63);
+				xlo = 2*lo;
+				q++;
+			} else {
+				xhi = 2*xhi + (xlo>>63);
+				xlo = 2*xlo;
+			}
+			q <<= 1;
+		}
+		hi = xhi - yhi;
+		lo = xlo - ylo;
+		if (xlo < ylo)
+			hi -= 1;
+		if (hi >> 63 == 0) {
+			xhi = hi;
+			xlo = lo;
+			q++;
+		}
+		if ((xhi|xlo) == 0)
+			ex = -120;
+		else
+			for (; xhi >> 48 == 0; xhi = 2*xhi + (xlo>>63), xlo = 2*xlo, ex--);
+		ux.i2.hi = xhi;
+		ux.i2.lo = xlo;
+#endif
+	}
+
+	/* scale result and decide between |x| and |x|-|y| */
+	if (ex <= 0) {
+		ux.i.se = ex + 120;
+		ux.f *= 0x1p-120f;
+	} else
+		ux.i.se = ex;
+	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;
+}
+#endif
-- 
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