| 1 | /* ===-- divsi3.c - Implement __divsi3 -------------------------------------=== |
| 2 | * |
| 3 | * The LLVM Compiler Infrastructure |
| 4 | * |
| 5 | * This file is dual licensed under the MIT and the University of Illinois Open |
| 6 | * Source Licenses. See LICENSE.TXT for details. |
| 7 | * |
| 8 | * ===----------------------------------------------------------------------=== |
| 9 | * |
| 10 | * This file implements __divsi3 for the compiler_rt library. |
| 11 | * |
| 12 | * ===----------------------------------------------------------------------=== |
| 13 | */ |
| 14 | |
| 15 | #include "int_lib.h" |
| 16 | |
| 17 | /* Returns: a / b */ |
| 18 | |
| 19 | ARM_EABI_FNALIAS(idiv, divsi3) |
| 20 | |
| 21 | COMPILER_RT_ABI si_int |
| 22 | __divsi3(si_int a, si_int b) |
| 23 | { |
| 24 | const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1; |
| 25 | si_int s_a = a >> bits_in_word_m1; /* s_a = a < 0 ? -1 : 0 */ |
| 26 | si_int s_b = b >> bits_in_word_m1; /* s_b = b < 0 ? -1 : 0 */ |
| 27 | a = (a ^ s_a) - s_a; /* negate if s_a == -1 */ |
| 28 | b = (b ^ s_b) - s_b; /* negate if s_b == -1 */ |
| 29 | s_a ^= s_b; /* sign of quotient */ |
| 30 | /* |
| 31 | * On CPUs without unsigned hardware division support, |
| 32 | * this calls __udivsi3 (notice the cast to su_int). |
| 33 | * On CPUs with unsigned hardware division support, |
| 34 | * this uses the unsigned division instruction. |
| 35 | */ |
| 36 | return ((su_int)a/(su_int)b ^ s_a) - s_a; /* negate if s_a == -1 */ |
| 37 | } |
| 38 | |