/* * 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; }