| //===-- muldi3.c - Implement __muldi3 -------------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements __muldi3 for the compiler_rt library. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "int_lib.h" |
| |
| // Returns: a * b |
| |
| static |
| di_int |
| __muldsi3(su_int a, su_int b) |
| { |
| dwords r; |
| const int bits_in_word_2 = (int)(sizeof(si_int) * CHAR_BIT) / 2; |
| const su_int lower_mask = (su_int)~0 >> bits_in_word_2; |
| r.low = (a & lower_mask) * (b & lower_mask); |
| su_int t = r.low >> bits_in_word_2; |
| r.low &= lower_mask; |
| t += (a >> bits_in_word_2) * (b & lower_mask); |
| r.low += (t & lower_mask) << bits_in_word_2; |
| r.high = t >> bits_in_word_2; |
| t = r.low >> bits_in_word_2; |
| r.low &= lower_mask; |
| t += (b >> bits_in_word_2) * (a & lower_mask); |
| r.low += (t & lower_mask) << bits_in_word_2; |
| r.high += t >> bits_in_word_2; |
| r.high += (a >> bits_in_word_2) * (b >> bits_in_word_2); |
| return r.all; |
| } |
| |
| // Returns: a * b |
| |
| di_int |
| __muldi3(di_int a, di_int b) |
| { |
| dwords x; |
| x.all = a; |
| dwords y; |
| y.all = b; |
| dwords r; |
| r.all = __muldsi3(x.low, y.low); |
| r.high += x.high * y.low + x.low * y.high; |
| return r.all; |
| } |