Standalone sis - initial commit

1 files changed, 84 insertions, 0 deletions

diff --git a/float.c b/float.c
new file mode 100644
index 0000000..f0a912c
--- /dev/null
+++ b/float.c
@@ -0,0 +1,84 @@
+/* This file is part of SIS (SPARC instruction simulator)
+
+   Copyright (C) 1995-2017 Free Software Foundation, Inc.
+   Contributed by Jiri Gaisler, European Space Agency
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+/* This file implements the interface between the host and the simulated
+   FPU.  IEEE trap handling is done as follows:
+     1. In the host, all IEEE traps are masked
+     2. After each simulated FPU instruction, check if any exception
+        occured by reading the exception bits from the host FPU status
+        register (get_accex()).
+     3. Propagate any exceptions to the simulated FSR.
+     4. Clear host exception bits.
+ */
+
+#include "config.h"
+#include "sis.h"
+#include <fenv.h>
+
+/* This routine should return the accrued exceptions */
+int
+get_accex()
+{
+    int fexc, accx;
+
+    fexc = fetestexcept (FE_ALL_EXCEPT);
+    accx = 0;
+    if (fexc & FE_INEXACT)
+        accx |= 1;
+    if (fexc & FE_DIVBYZERO)
+        accx |= 2;
+    if (fexc & FE_UNDERFLOW)
+        accx |= 4;
+    if (fexc & FE_OVERFLOW)
+        accx |= 8;
+    if (fexc & FE_INVALID)
+        accx |= 0x10;
+    return accx;
+}
+
+/* How to clear the accrued exceptions */
+void
+clear_accex()
+{
+    feclearexcept (FE_ALL_EXCEPT);
+}
+
+/* How to map SPARC FSR onto the host */
+void
+set_fsr(fsr)
+uint32 fsr;
+{
+    int fround;
+
+    fsr >>= 30;
+    switch (fsr) {
+	case 0: 
+	    fround = FE_TONEAREST;
+	    break;
+	case 1:
+	    fround = FE_TOWARDZERO;
+	    break;
+	case 2:
+	    fround = FE_UPWARD;
+	    break;
+	case 3:
+	    fround = FE_DOWNWARD;
+	    break;
+     }
+     fesetround (fround);
+}