1 files changed, 123 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p32_to_p8.c b/source/luametatex/source/libraries/softposit/source/p32_to_p8.c
new file mode 100644
index 000000000..270545cf2
--- /dev/null
+++ b/source/luametatex/source/libraries/softposit/source/p32_to_p8.c
@@ -0,0 +1,123 @@
+
+/*============================================================================
+
+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.
+
+This C source file was based on SoftFloat IEEE Floating-Point Arithmetic
+Package, Release 3d, by John R. Hauser.
+
+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 "platform.h"
+#include "internals.h"
+
+posit8_t pX2_to_p8( posit_2_t pA ){
+	posit32_t p32 = {.v = pA.v};
+	return p32_to_p8(p32);
+}
+
+posit8_t p32_to_p8( posit32_t pA ){
+
+	union ui32_p32 uA;
+	union ui8_p8 uZ;
+	uint_fast32_t uiA, tmp=0, regime;
+	uint_fast32_t exp_frac32A=0;
+	bool sign, regSA, bitsMore=0, bitNPlusOne=0;
+	int_fast8_t kA=0, regA;
+
+	uA.p = pA;
+	uiA = uA.ui;
+
+	if (uiA==0x80000000 || uiA==0 ){
+		uZ.ui = (uint8_t)(uiA>>24) &0xFF;
+		return uZ.p;
+	}
+
+
+	sign = signP32UI( uiA );
+	if (sign) uiA = -uiA & 0xFFFFFFFF;
+
+	if (uiA>0x66000000) uZ.ui = 0x7F;
+	else if (uiA<0x1A000000) uZ.ui = 0x1;
+	else{
+		regSA = signregP32UI(uiA);
+		//regime
+		tmp = (uiA<<2)&0xFFFFFFFF;
+		if (regSA){
+			while (tmp>>31){
+				kA++;
+				tmp= (tmp<<1) & 0xFFFFFFFF;
+			}
+		}
+		else{
+			kA=-1;
+			while (!(tmp>>31)){
+				kA--;
+				tmp= (tmp<<1) & 0xFFFFFFFF;
+			}
+			tmp&=0x7FFFFFFF;
+		}
+
+		//2nd and 3rd bit exp
+		exp_frac32A = tmp;
+
+		if(kA<0){
+			regA = ((-kA)<<2) - (exp_frac32A>>29);
+
+			if (regA==0) regA=1;
+			regSA = 0;
+			regime = (regA>6) ? (0x1) : (0x40>>regA);
+
+		}
+		else{
+			(kA==0)?(regA=1 + (exp_frac32A>>29)): (regA = (kA<<2) + (exp_frac32A>>29) +1);
+			regSA=1;
+			regime = 0x7F - (0x7F>>regA);
+		}
+		exp_frac32A = (exp_frac32A<<3) &0xFFFFFFFF;
+		if (regA>5){
+			uZ.ui = regime;
+		}
+		else{
+			//exp_frac32A= ((exp_frac32A)&0x3F) >> shift; //first 2 bits already empty (for sign and regime terminating bit)
+			uZ.ui = regime | ( exp_frac32A>>(regA+26) );
+		}
+		if ( exp_frac32A & (0x2000000<<regA) ){
+			bitsMore = exp_frac32A & (0xFFFFFFFF>>(7-regA));
+			uZ.ui += (uZ.ui&1) | bitsMore;
+		}
+	}
+
+
+	if (sign) uZ.ui = -uZ.ui & 0xFF;
+	return uZ.p;
+}
+