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-rw-r--r--src/zpowu.c32
1 files changed, 32 insertions, 0 deletions
diff --git a/src/zpowu.c b/src/zpowu.c
new file mode 100644
index 0000000..bc0c6dd
--- /dev/null
+++ b/src/zpowu.c
@@ -0,0 +1,32 @@
+/* See LICENSE file for copyright and license details. */
+#include "internals"
+
+#include <errno.h>
+
+#define tb libzahl_tmp_pow_b
+
+
+void
+zpowu(z_t a, z_t b, unsigned long long int c)
+{
+ if (!c) {
+ if (zzero(b)) {
+ errno = EDOM; /* Indeterminate form: 0:th power of 0 */
+ FAILURE_JUMP();
+ }
+ zsetu(a, 1);
+ return;
+ } else if (zzero(b)) {
+ SET_SIGNUM(a, 0);
+ return;
+ }
+
+ zset(tb, b);
+ zsetu(a, 1);
+
+ for (; c; c >>= 1) {
+ if (c & 1)
+ zmul(a, a, tb);
+ zsqr(tb, tb);
+ }
+}