[sim] added SoftFloat-3 source

[riscv-isa-sim.git] / softfloat / SoftFloat-3 / source / s_countLeadingZeros64.c

diff --git a/softfloat/SoftFloat-3/source/s_countLeadingZeros64.c b/softfloat/SoftFloat-3/source/s_countLeadingZeros64.c
new file mode 100755 (executable)
index 0000000..4a96cf6
--- /dev/null
+++ b/softfloat/SoftFloat-3/source/s_countLeadingZeros64.c
@@ -0,0 +1,31 @@
+
+#include <stdint.h>
+#include "primitives.h"
+
+int softfloat_countLeadingZeros64( uint64_t a )
+{
+    int count;
+    uint32_t a32;
+
+    count = 32;
+    a32 = a;
+    if ( UINT64_C( 0x100000000 ) <= a ) {
+        count = 0;
+        a32 = a>>32;
+    }
+    /*------------------------------------------------------------------------
+    | From here, result is current count + count leading zeros of `a32'.
+    *------------------------------------------------------------------------*/
+    if ( a32 < 0x10000 ) {
+        count += 16;
+        a32 <<= 16;
+    }
+    if ( a32 < 0x1000000 ) {
+        count += 8;
+        a32 <<= 8;
+    }
+    count += softfloat_countLeadingZeros8[ a32>>24 ];
+    return count;
+
+}
+