diff options
Diffstat (limited to 'compiler-rt/lib/builtins/divsi3.c')
| -rw-r--r-- | compiler-rt/lib/builtins/divsi3.c | 49 |
1 files changed, 24 insertions, 25 deletions
diff --git a/compiler-rt/lib/builtins/divsi3.c b/compiler-rt/lib/builtins/divsi3.c index 775cdccf9b7..754d1036226 100644 --- a/compiler-rt/lib/builtins/divsi3.c +++ b/compiler-rt/lib/builtins/divsi3.c @@ -1,34 +1,33 @@ -/* ===-- divsi3.c - Implement __divsi3 -------------------------------------=== - * - * Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. - * See https://llvm.org/LICENSE.txt for license information. - * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception - * - * ===----------------------------------------------------------------------=== - * - * This file implements __divsi3 for the compiler_rt library. - * - * ===----------------------------------------------------------------------=== - */ +//===-- divsi3.c - Implement __divsi3 -------------------------------------===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// This file implements __divsi3 for the compiler_rt library. +// +//===----------------------------------------------------------------------===// #include "int_lib.h" -/* Returns: a / b */ +// Returns: a / b COMPILER_RT_ABI si_int __divsi3(si_int a, si_int b) { const int bits_in_word_m1 = (int)(sizeof(si_int) * CHAR_BIT) - 1; - si_int s_a = a >> bits_in_word_m1; /* s_a = a < 0 ? -1 : 0 */ - si_int s_b = b >> bits_in_word_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 */ - /* - * On CPUs without unsigned hardware division support, - * this calls __udivsi3 (notice the cast to su_int). - * On CPUs with unsigned hardware division support, - * this uses the unsigned division instruction. - */ - return ((su_int)a / (su_int)b ^ s_a) - s_a; /* negate if s_a == -1 */ + si_int s_a = a >> bits_in_word_m1; // s_a = a < 0 ? -1 : 0 + si_int s_b = b >> bits_in_word_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 + // + // On CPUs without unsigned hardware division support, + // this calls __udivsi3 (notice the cast to su_int). + // On CPUs with unsigned hardware division support, + // this uses the unsigned division instruction. + // + return ((su_int)a / (su_int)b ^ s_a) - s_a; // negate if s_a == -1 } #if defined(__ARM_EABI__) |
