cosmopolitan/third_party/compiler_rt/divsi3.c
Justine Tunney 7e0a09feec
Mint APE Loader v1.5
This change ports APE Loader to Linux AARCH64, so that Raspberry Pi
users can run programs like redbean, without the executable needing
to modify itself. Progress has also slipped into this change on the
issue of making progress better conforming to user expectations and
industry standards regarding which symbols we're allowed to declare
2023-07-26 13:54:49 -07:00

42 lines
1.5 KiB
C

/* clang-format off */
/* ===-- divsi3.c - Implement __divsi3 -------------------------------------===
*
* 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 __divsi3 for the compiler_rt library.
*
* ===----------------------------------------------------------------------===
*/
__static_yoink("huge_compiler_rt_license");
#include "third_party/compiler_rt/int_lib.h"
/* 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 */
}
#if defined(__ARM_EABI__)
AEABI_RTABI si_int __aeabi_idiv(si_int a, si_int b) COMPILER_RT_ALIAS(__divsi3);
#endif