1 files changed, 88 insertions, 0 deletions
diff --git a/source/luametatex/source/libraries/softposit/source/p8_sub.c b/source/luametatex/source/libraries/softposit/source/p8_sub.c
new file mode 100644
index 000000000..31c05d874
--- /dev/null
+++ b/source/luametatex/source/libraries/softposit/source/p8_sub.c
@@ -0,0 +1,88 @@
+
+/*============================================================================
+
+This C source file is part of the SoftPosit Posit Arithmetic Package
+by S. H. Leong (Cerlane).
+
+Copyright 2017 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 "platform.h"
+#include "internals.h"
+
+posit8_t p8_sub( posit8_t a, posit8_t b ){
+
+    union ui8_p8 uA, uB;
+    uint_fast8_t uiA, uiB;
+    union ui8_p8 uZ;
+
+    uA.p = a;
+	uiA = uA.ui;
+	uB.p = b;
+	uiB = uB.ui;
+
+
+
+#ifdef SOFTPOSIT_EXACT
+		uZ.ui.exact = (uiA.ui.exact & uiB.ui.exact);
+#endif
+
+    //infinity
+	if ( uiA==0x80 || uiB==0x80 ){
+#ifdef SOFTPOSIT_EXACT
+		uZ.ui.v = 0x80;
+		uZ.ui.exact = 0;
+#else
+		uZ.ui = 0x80;
+#endif
+		return uZ.p;
+	}
+    //Zero
+	else if ( uiA==0 || uiB==0 ){
+#ifdef SOFTPOSIT_EXACT
+		uZ.ui.v = (uiA | -uiB);
+		uZ.ui.exact = 0;
+#else
+		uZ.ui = (uiA | -uiB);
+#endif
+		return uZ.p;
+	}
+
+	//different signs
+	if (signP8UI(uiA^uiB))
+		return softposit_addMagsP8(uiA, (-uiB & 0xFF));
+	else
+		return softposit_subMagsP8(uiA, (-uiB & 0xFF));
+
+
+
+
+}
+