| /* |
| * This file is part of the libpayload project. |
| * |
| * Copyright 2014 Google Inc. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include <libpayload-config.h> |
| #include <stdlib.h> |
| |
| #if !IS_ENABLED(CONFIG_LP_LITTLE_ENDIAN) |
| #error this code is for little endian only |
| #endif |
| |
| union overlay64 { |
| uint64_t longw; |
| struct { |
| uint32_t lower; |
| uint32_t higher; |
| } words; |
| }; |
| |
| |
| uint64_t __ashldi3(uint64_t num, unsigned shift) |
| { |
| union overlay64 output; |
| |
| output.longw = num; |
| if (shift >= 32) { |
| output.words.higher = output.words.lower << (shift - 32); |
| output.words.lower = 0; |
| } else { |
| if (!shift) |
| return num; |
| output.words.higher = (output.words.higher << shift) | |
| (output.words.lower >> (32 - shift)); |
| output.words.lower = output.words.lower << shift; |
| } |
| return output.longw; |
| } |
| |
| uint64_t __lshrdi3(uint64_t num, unsigned shift) |
| { |
| union overlay64 output; |
| |
| output.longw = num; |
| if (shift >= 32) { |
| output.words.lower = output.words.higher >> (shift - 32); |
| output.words.higher = 0; |
| } else { |
| if (!shift) |
| return num; |
| output.words.lower = output.words.lower >> shift | |
| (output.words.higher << (32 - shift)); |
| output.words.higher = output.words.higher >> shift; |
| } |
| return output.longw; |
| } |
| |
| #define MAX_32BIT_UINT ((((uint64_t)1) << 32) - 1) |
| |
| static uint64_t _64bit_divide(uint64_t dividend, |
| uint64_t divider, uint64_t *rem_p) |
| { |
| uint64_t result = 0; |
| |
| /* |
| * If divider is zero - let the rest of the system care about the |
| * exception. |
| */ |
| if (!divider) |
| return 1/(uint32_t)divider; |
| |
| /* As an optimization, let's not use 64 bit division unless we must. */ |
| if (dividend <= MAX_32BIT_UINT) { |
| if (divider > MAX_32BIT_UINT) { |
| result = 0; |
| if (rem_p) |
| *rem_p = divider; |
| } else { |
| result = (uint32_t) dividend / (uint32_t) divider; |
| if (rem_p) |
| *rem_p = (uint32_t) dividend % |
| (uint32_t) divider; |
| } |
| return result; |
| } |
| |
| while (divider <= dividend) { |
| uint64_t locald = divider; |
| uint64_t limit = __lshrdi3(dividend, 1); |
| int shifts = 0; |
| |
| while (locald <= limit) { |
| shifts++; |
| locald = locald + locald; |
| } |
| result |= __ashldi3(1, shifts); |
| dividend -= locald; |
| } |
| |
| if (rem_p) |
| *rem_p = dividend; |
| |
| return result; |
| } |
| |
| uint64_t __udivdi3(uint64_t num, uint64_t den) |
| { |
| return _64bit_divide(num, den, NULL); |
| } |
| |
| uint64_t __umoddi3(uint64_t num, uint64_t den) |
| { |
| uint64_t v = 0; |
| |
| _64bit_divide(num, den, &v); |
| return v; |
| } |