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;
+}