1 files changed, 41 insertions, 0 deletions
diff --git a/reference/C/CONTRIB/SNIP/ldfloor.c b/reference/C/CONTRIB/SNIP/ldfloor.c
new file mode 100755
index 0000000..acea285
--- /dev/null
+++ b/reference/C/CONTRIB/SNIP/ldfloor.c
@@ -0,0 +1,41 @@
+/* ldfloor() -- long double floor
+** public domain by Raymond Gardner  Englewood, CO
+** tested with TC++
+** assumptions: 80-bit IEEE format numbers, stored LSB first 
+**   (Intel style), longs & ints are accessed from arbitrary boundaries
+*/
+
+long double ldfloor(long double a)
+{
+    long double a0;
+    int e, n;
+   
+    a0 = a;
+    e = ((int *)&a)[4] & 0x7FFF;        /* extract exponent         */
+    if ( e == 0 )                       /* 0 is special case        */
+        return (long double) 0.0;
+    e -= 16383;                         /* unbias exponent          */
+    if (e < 0)                          /* if < 0, num is < 1,...   */
+    {
+        a = 0.0;                        /* so floor is zero         */
+    }
+    else if ((n = 63 - e) > 0)          /* clear n least sig. bits  */
+    {
+        if (n < 32)                     /* clear n lowest bits      */
+        {
+            ((unsigned long *)&a)[0] &= ~((1L << n) - 1);
+        }
+        else                            /* n >= 32 */
+        {
+            ((unsigned long *)&a)[0] = 0; /* clear lower 32 bits            */
+            n -= 32;                    /* how many left to clear ?         */
+            if (n)                      /* if any, clear n next lowest bits */
+            {
+                ((unsigned long *)&a)[1] &= ~((1L << n) - 1);
+            }
+        }
+    }
+    if (a0 < 0 && a0 != a)          /* if neg. and it had fractional bits */
+        a -= 1.0;                   /* adjust the floor                   */
+    return a;                       /* return it                          */
+}