Update SoftFloat

1 files changed, 136 insertions, 0 deletions

diff --git a/softfloat/f16_sqrt.c b/softfloat/f16_sqrt.c
new file mode 100644
index 0000000..7ff2923
--- /dev/null
+++ b/softfloat/f16_sqrt.c
@@ -0,0 +1,136 @@
+
+/*============================================================================
+
+This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
+Package, Release 3d, by John R. Hauser.
+
+Copyright 2011, 2012, 2013, 2014, 2015, 2016 The Regents of the University of
+California.  All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+ 1. Redistributions of source code must retain the above copyright notice,
+    this list of conditions, and the following disclaimer.
+
+ 2. Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions, and the following disclaimer in the documentation
+    and/or other materials provided with the distribution.
+
+ 3. Neither the name of the University nor the names of its contributors may
+    be used to endorse or promote products derived from this software without
+    specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
+EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
+DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+=============================================================================*/
+
+#include <stdbool.h>
+#include <stdint.h>
+#include "platform.h"
+#include "internals.h"
+#include "specialize.h"
+#include "softfloat.h"
+
+extern const uint16_t softfloat_approxRecipSqrt_1k0s[];
+extern const uint16_t softfloat_approxRecipSqrt_1k1s[];
+
+float16_t f16_sqrt( float16_t a )
+{
+    union ui16_f16 uA;
+    uint_fast16_t uiA;
+    bool signA;
+    int_fast8_t expA;
+    uint_fast16_t sigA, uiZ;
+    struct exp8_sig16 normExpSig;
+    int_fast8_t expZ;
+    int index;
+    uint_fast16_t r0;
+    uint_fast32_t ESqrR0;
+    uint16_t sigma0;
+    uint_fast16_t recipSqrt16, sigZ, shiftedSigZ;
+    uint16_t negRem;
+    union ui16_f16 uZ;
+
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    uA.f = a;
+    uiA = uA.ui;
+    signA = signF16UI( uiA );
+    expA  = expF16UI( uiA );
+    sigA  = fracF16UI( uiA );
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    if ( expA == 0x1F ) {
+        if ( sigA ) {
+            uiZ = softfloat_propagateNaNF16UI( uiA, 0 );
+            goto uiZ;
+        }
+        if ( ! signA ) return a;
+        goto invalid;
+    }
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    if ( signA ) {
+        if ( ! (expA | sigA) ) return a;
+        goto invalid;
+    }
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    if ( ! expA ) {
+        if ( ! sigA ) return a;
+        normExpSig = softfloat_normSubnormalF16Sig( sigA );
+        expA = normExpSig.exp;
+        sigA = normExpSig.sig;
+    }
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    expZ = ((expA - 0xF)>>1) + 0xE;
+    expA &= 1;
+    sigA |= 0x0400;
+    index = (sigA>>6 & 0xE) + expA;
+    r0 = softfloat_approxRecipSqrt_1k0s[index]
+             - (((uint_fast32_t) softfloat_approxRecipSqrt_1k1s[index]
+                     * (sigA & 0x7F))
+                    >>11);
+    ESqrR0 = ((uint_fast32_t) r0 * r0)>>1;
+    if ( expA ) ESqrR0 >>= 1;
+    sigma0 = ~(uint_fast16_t) ((ESqrR0 * sigA)>>16);
+    recipSqrt16 = r0 + (((uint_fast32_t) r0 * sigma0)>>25);
+    if ( ! (recipSqrt16 & 0x8000) ) recipSqrt16 = 0x8000;
+    sigZ = ((uint_fast32_t) (sigA<<5) * recipSqrt16)>>16;
+    if ( expA ) sigZ >>= 1;
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    ++sigZ;
+    if ( ! (sigZ & 7) ) {
+        shiftedSigZ = sigZ>>1;
+        negRem = shiftedSigZ * shiftedSigZ;
+        sigZ &= ~1;
+        if ( negRem & 0x8000 ) {
+            sigZ |= 1;
+        } else {
+            if ( negRem ) --sigZ;
+        }
+    }
+    return softfloat_roundPackToF16( 0, expZ, sigZ );
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+ invalid:
+    softfloat_raiseFlags( softfloat_flag_invalid );
+    uiZ = defaultNaNF16UI;
+ uiZ:
+    uZ.ui = uiZ;
+    return uZ.f;
+
+}
+