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authorDimitry Andric <dim@FreeBSD.org>2015-01-07 19:55:37 +0000
committerDimitry Andric <dim@FreeBSD.org>2015-01-07 19:55:37 +0000
commitca9211ecdede9bdedb812b2243a4abdb8dacd1b9 (patch)
tree9b19e801150082c33e9152275829a6ce90614b55 /lib/builtins/divdi3.c
parent8ef50bf3d1c287b5013c3168de77a462dfce3495 (diff)
Notes
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diff --git a/lib/builtins/divdi3.c b/lib/builtins/divdi3.c
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+/* ===-- divdi3.c - Implement __divdi3 -------------------------------------===
+ *
+ * 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 __divdi3 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#include "int_lib.h"
+
+/* Returns: a / b */
+
+COMPILER_RT_ABI di_int
+__divdi3(di_int a, di_int b)
+{
+ const int bits_in_dword_m1 = (int)(sizeof(di_int) * CHAR_BIT) - 1;
+ di_int s_a = a >> bits_in_dword_m1; /* s_a = a < 0 ? -1 : 0 */
+ di_int s_b = b >> bits_in_dword_m1; /* s_b = b < 0 ? -1 : 0 */
+ a = (a ^ s_a) - s_a; /* negate if s_a == -1 */
+ b = (b ^ s_b) - s_b; /* negate if s_b == -1 */
+ s_a ^= s_b; /*sign of quotient */
+ return (__udivmoddi4(a, b, (du_int*)0) ^ s_a) - s_a; /* negate if s_a == -1 */
+}