Initial revision

[cln.git] / src / integer / bitwise / cl_I_logbitp_I.cc

diff --git a/src/integer/bitwise/cl_I_logbitp_I.cc b/src/integer/bitwise/cl_I_logbitp_I.cc
new file mode 100644 (file)
index 0000000..2b58a56
--- /dev/null
+++ b/src/integer/bitwise/cl_I_logbitp_I.cc
@@ -0,0 +1,50 @@
+// logbitp().
+
+// General includes.
+#include "cl_sysdep.h"
+
+// Specification.
+#include "cl_integer.h"
+
+
+// Implementation.
+
+#include "cl_I.h"
+#include "cl_DS.h"
+#include "cl_io.h"
+#include "cl_integer_io.h"
+#include "cl_abort.h"
+
+cl_boolean logbitp (const cl_I& x, const cl_I& y)
+{
+    // Methode:
+    // Falls x<0, Error.
+    // Falls x>=0: Falls x>=intDsize*Länge(y), teste Vorzeichen von y.
+    //             Sonst x=intDsize*k+i, Teste Bit i vom Worte Nr. k+1 (von oben herab).
+      if (!minusp(x)) // x>=0 ?
+        { if (fixnump(x))
+            { var uintL x_ = FN_to_L(x);
+              var uintC ylen;
+              var const uintD* yLSDptr;
+              I_to_NDS_nocopy(y, ,ylen=,yLSDptr=,cl_true, { return cl_false; } ); // DS zu y
+              if (x_ < intDsize*(uintL)ylen)
+                // x ist ein Fixnum >=0, < intDsize*ylen
+                { if (lspref(yLSDptr,floor(x_,intDsize)) & bit(x_%intDsize))
+                    return cl_true;
+                    else
+                    return cl_false;
+            }   }
+          // Vorzeichen von y testen
+          if (minusp(y))
+            return cl_true;
+            else
+            return cl_false;
+        }
+        else
+        // x<0
+        { fprint(cl_stderr, "logbitp: Index is negative: ");
+          fprint(cl_stderr, x);
+          fprint(cl_stderr, "\n");
+          cl_abort();
+        }
+}