| Daniel Dunbar | fd08999 | 2009-06-26 16:47:03 +0000 | [diff] [blame] | 1 | //===-- divsi3.c - Implement __divsi3 -------------------------------------===// |
| 2 | // |
| 3 | // The LLVM Compiler Infrastructure |
| 4 | // |
| 5 | // This file is distributed under the University of Illinois Open Source |
| 6 | // License. See LICENSE.TXT for details. |
| 7 | // |
| 8 | //===----------------------------------------------------------------------===// |
| 9 | // |
| 10 | // This file implements __divsi3 for the compiler_rt library. |
| 11 | // |
| 12 | //===----------------------------------------------------------------------===// |
| 13 | |
| 14 | #include "int_lib.h" |
| 15 | |
| 16 | su_int __udivsi3(su_int n, su_int d); |
| 17 | |
| 18 | // Returns: a / b |
| 19 | |
| 20 | si_int |
| 21 | __divsi3(si_int a, si_int b) |
| 22 | { |
| 23 | const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1; |
| 24 | si_int s_a = a >> bits_in_word_m1; // s_a = a < 0 ? -1 : 0 |
| 25 | si_int s_b = b >> bits_in_word_m1; // s_b = b < 0 ? -1 : 0 |
| 26 | a = (a ^ s_a) - s_a; // negate if s_a == -1 |
| 27 | b = (b ^ s_b) - s_b; // negate if s_b == -1 |
| 28 | s_a ^= s_b; // sign of quotient |
| 29 | return (__udivsi3(a, b) ^ s_a) - s_a; // negate if s_a == -1 |
| 30 | } |