1 files changed, 98 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/c_convertPosit8ToDec.c b/source/luametatex/source/libraries/softposit/source/c_convertPosit8ToDec.c
new file mode 100644
index 000000000..f8af0b97f
--- /dev/null
+++ b/source/luametatex/source/libraries/softposit/source/c_convertPosit8ToDec.c
@@ -0,0 +1,98 @@
+
+/*============================================================================
+
+This C source file is part of the SoftPosit Posit Arithmetic Package
+by S. H. Leong (Cerlane).
+
+Copyright 2017, 2018 A*STAR.  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 <math.h>
+
+#include "platform.h"
+#include "internals.h"
+
+
+double convertP8ToDouble(posit8_t a){
+	union ui8_p8 uZ;
+	double d8;
+	uZ.p = a;
+
+	if (uZ.ui==0){
+		return 0;
+	}
+	else if(uZ.ui==0x7F){ //maxpos
+		return 64;
+	}
+	else if (uZ.ui==0x81){ //-maxpos
+		return -64;
+	}
+	else if (uZ.ui == 0x80){ //NaR
+		return NAN;
+	}
+
+	bool regS, sign;
+	uint_fast8_t reg, shift=2, frac;
+	int_fast8_t k=0;
+	double fraction_max;
+
+	sign = signP8UI( uZ.ui );
+	if (sign) uZ.ui = -uZ.ui & 0xFF;
+	regS = signregP8UI( uZ.ui );
+
+	uint_fast8_t tmp = (uZ.ui<<2) & 0xFF;
+	if (regS){
+		while (tmp>>7){
+			k++;
+			shift++;
+			tmp= (tmp<<1) & 0xFF;
+		}
+		reg = k+1;
+	}
+	else{
+		k=-1;
+		while (!(tmp>>7)){
+			k--;
+			shift++;
+			tmp= (tmp<<1) & 0xFF;
+		}
+		tmp&=0x7F;
+		reg =-k;
+	}
+	frac = (tmp & 0x7F) >> shift;
+
+
+	fraction_max = pow(2, 6-reg) ;
+	d8 = (double)( pow(2, k) * (1+((double)frac/fraction_max)) );
+
+	if (sign)
+		d8 = -d8;
+
+	return d8;
+}