Initial import

third_party/compiler_rt/udivsi3.c

@@ -0,0 +1,71 @@
+/* clang-format off */
+/* ===-- udivsi3.c - Implement __udivsi3 -----------------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __udivsi3 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+STATIC_YOINK("huge_compiler_rt_license");
+
+#include "third_party/compiler_rt/int_lib.h"
+
+/* Returns: a / b */
+
+/* Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide */
+
+/* This function should not call __divsi3! */
+COMPILER_RT_ABI su_int
+__udivsi3(su_int n, su_int d)
+{
+    const unsigned n_uword_bits = sizeof(su_int) * CHAR_BIT;
+    su_int q;
+    su_int r;
+    unsigned sr;
+    /* special cases */
+    if (d == 0)
+        return 0; /* ?! */
+    if (n == 0)
+        return 0;
+    sr = __builtin_clz(d) - __builtin_clz(n);
+    /* 0 <= sr <= n_uword_bits - 1 or sr large */
+    if (sr > n_uword_bits - 1)  /* d > r */
+        return 0;
+    if (sr == n_uword_bits - 1)  /* d == 1 */
+        return n;
+    ++sr;
+    /* 1 <= sr <= n_uword_bits - 1 */
+    /* Not a special case */
+    q = n << (n_uword_bits - sr);
+    r = n >> sr;
+    su_int carry = 0;
+    for (; sr > 0; --sr)
+    {
+        /* r:q = ((r:q)  << 1) | carry */
+        r = (r << 1) | (q >> (n_uword_bits - 1));
+        q = (q << 1) | carry;
+        /* carry = 0;
+         * if (r.all >= d.all)
+         * {
+         *      r.all -= d.all;
+         *      carry = 1;
+         * }
+         */
+        const si_int s = (si_int)(d - r - 1) >> (n_uword_bits - 1);
+        carry = s & 1;
+        r -= d & s;
+    }
+    q = (q << 1) | carry;
+    return q;
+}
+
+#if defined(__ARM_EABI__)
+AEABI_RTABI su_int __aeabi_uidiv(su_int n, su_int d) COMPILER_RT_ALIAS(__udivsi3);
+#endif