| /* ===-- udivsi3.c - Implement __udivsi3 -----------------------------------=== |
| * |
| * 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 __udivsi3 for the compiler_rt library. |
| * |
| * ===----------------------------------------------------------------------=== |
| */ |
| |
| #include "int_lib.h" |
| |
| /* Returns: a / b */ |
| |
| /* Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide */ |
| |
| /* This function should not call __divsi3! */ |
| COMPILER_RT_ABI su_int |
| __udivsi3(su_int n, su_int d) |
| { |
| const unsigned n_uword_bits = sizeof(su_int) * CHAR_BIT; |
| su_int q; |
| su_int r; |
| unsigned sr; |
| /* special cases */ |
| if (d == 0) |
| return 0; /* ?! */ |
| if (n == 0) |
| return 0; |
| sr = __builtin_clz(d) - __builtin_clz(n); |
| /* 0 <= sr <= n_uword_bits - 1 or sr large */ |
| if (sr > n_uword_bits - 1) /* d > r */ |
| return 0; |
| if (sr == n_uword_bits - 1) /* d == 1 */ |
| return n; |
| ++sr; |
| /* 1 <= sr <= n_uword_bits - 1 */ |
| /* Not a special case */ |
| q = n << (n_uword_bits - sr); |
| r = n >> sr; |
| su_int carry = 0; |
| for (; sr > 0; --sr) |
| { |
| /* r:q = ((r:q) << 1) | carry */ |
| r = (r << 1) | (q >> (n_uword_bits - 1)); |
| q = (q << 1) | carry; |
| /* carry = 0; |
| * if (r.all >= d.all) |
| * { |
| * r.all -= d.all; |
| * carry = 1; |
| * } |
| */ |
| const si_int s = (si_int)(d - r - 1) >> (n_uword_bits - 1); |
| carry = s & 1; |
| r -= d & s; |
| } |
| q = (q << 1) | carry; |
| return q; |
| } |
| |
| #if defined(__ARM_EABI__) |
| AEABI_RTABI su_int __aeabi_uidiv(su_int n, su_int d) COMPILER_RT_ALIAS(__udivsi3); |
| #endif |
