Update SoftFloat

[riscv-isa-sim.git] / softfloat / f128_to_f64.c

diff --git a/softfloat/f128_to_f64.c b/softfloat/f128_to_f64.c
new file mode 100644 (file)
index 0000000..e7aec20
--- /dev/null
+++ b/softfloat/f128_to_f64.c
@@ -0,0 +1,100 @@
+
+/*============================================================================
+
+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 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"
+
+float64_t f128_to_f64( float128_t a )
+{
+    union ui128_f128 uA;
+    uint_fast64_t uiA64, uiA0;
+    bool sign;
+    int_fast32_t exp;
+    uint_fast64_t frac64, frac0;
+    struct commonNaN commonNaN;
+    uint_fast64_t uiZ;
+    struct uint128 frac128;
+    union ui64_f64 uZ;
+
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    uA.f = a;
+    uiA64 = uA.ui.v64;
+    uiA0  = uA.ui.v0;
+    sign  = signF128UI64( uiA64 );
+    exp   = expF128UI64( uiA64 );
+    frac64 = fracF128UI64( uiA64 );
+    frac0  = uiA0;
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    if ( exp == 0x7FFF ) {
+        if ( frac64 | frac0 ) {
+            softfloat_f128UIToCommonNaN( uiA64, uiA0, &commonNaN );
+            uiZ = softfloat_commonNaNToF64UI( &commonNaN );
+        } else {
+            uiZ = packToF64UI( sign, 0x7FF, 0 );
+        }
+        goto uiZ;
+    }
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    frac128 = softfloat_shortShiftLeft128( frac64, frac0, 14 );
+    frac64 = frac128.v64 | (frac128.v0 != 0);
+    if ( ! (exp | frac64) ) {
+        uiZ = packToF64UI( sign, 0, 0 );
+        goto uiZ;
+    }
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+    exp -= 0x3C01;
+    if ( sizeof (int_fast16_t) < sizeof (int_fast32_t) ) {
+        if ( exp < -0x1000 ) exp = -0x1000;
+    }
+    return
+        softfloat_roundPackToF64(
+            sign, exp, frac64 | UINT64_C( 0x4000000000000000 ) );
+    /*------------------------------------------------------------------------
+    *------------------------------------------------------------------------*/
+ uiZ:
+    uZ.ui = uiZ;
+    return uZ.f;
+
+}
+