1 files changed, 103 insertions, 0 deletions
diff --git a/arch/mips/math-emu/sp_sqrt.c b/arch/mips/math-emu/sp_sqrt.c
new file mode 100644
index 000000000..e9bb60121
--- /dev/null
+++ b/arch/mips/math-emu/sp_sqrt.c
@@ -0,0 +1,103 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* IEEE754 floating point arithmetic
+ * single precision square root
+ */
+/*
+ * MIPS floating point support
+ * Copyright (C) 1994-2000 Algorithmics Ltd.
+ */
+
+#include "ieee754sp.h"
+
+union ieee754sp ieee754sp_sqrt(union ieee754sp x)
+{
+	int ix, s, q, m, t, i;
+	unsigned int r;
+	COMPXSP;
+
+	/* take care of Inf and NaN */
+
+	EXPLODEXSP;
+	ieee754_clearcx();
+	FLUSHXSP;
+
+	/* x == INF or NAN? */
+	switch (xc) {
+	case IEEE754_CLASS_SNAN:
+		return ieee754sp_nanxcpt(x);
+
+	case IEEE754_CLASS_QNAN:
+		/* sqrt(Nan) = Nan */
+		return x;
+
+	case IEEE754_CLASS_ZERO:
+		/* sqrt(0) = 0 */
+		return x;
+
+	case IEEE754_CLASS_INF:
+		if (xs) {
+			/* sqrt(-Inf) = Nan */
+			ieee754_setcx(IEEE754_INVALID_OPERATION);
+			return ieee754sp_indef();
+		}
+		/* sqrt(+Inf) = Inf */
+		return x;
+
+	case IEEE754_CLASS_DNORM:
+	case IEEE754_CLASS_NORM:
+		if (xs) {
+			/* sqrt(-x) = Nan */
+			ieee754_setcx(IEEE754_INVALID_OPERATION);
+			return ieee754sp_indef();
+		}
+		break;
+	}
+
+	ix = x.bits;
+
+	/* normalize x */
+	m = (ix >> 23);
+	if (m == 0) {		/* subnormal x */
+		for (i = 0; (ix & 0x00800000) == 0; i++)
+			ix <<= 1;
+		m -= i - 1;
+	}
+	m -= 127;		/* unbias exponent */
+	ix = (ix & 0x007fffff) | 0x00800000;
+	if (m & 1)		/* odd m, double x to make it even */
+		ix += ix;
+	m >>= 1;		/* m = [m/2] */
+
+	/* generate sqrt(x) bit by bit */
+	ix += ix;
+	s = 0;
+	q = 0;			/* q = sqrt(x) */
+	r = 0x01000000;		/* r = moving bit from right to left */
+
+	while (r != 0) {
+		t = s + r;
+		if (t <= ix) {
+			s = t + r;
+			ix -= t;
+			q += r;
+		}
+		ix += ix;
+		r >>= 1;
+	}
+
+	if (ix != 0) {
+		ieee754_setcx(IEEE754_INEXACT);
+		switch (ieee754_csr.rm) {
+		case FPU_CSR_RU:
+			q += 2;
+			break;
+		case FPU_CSR_RN:
+			q += (q & 1);
+			break;
+		}
+	}
+	ix = (q >> 1) + 0x3f000000;
+	ix += (m << 23);
+	x.bits = ix;
+	return x;
+}