113 lines
2.1 KiB
C
113 lines
2.1 KiB
C
// SPDX-License-Identifier: BSD-3-Clause
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/*
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* This file is copied from the coreboot repository as part of
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* the libpayload project:
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*
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* Copyright 2014 Google Inc.
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*/
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#include <common.h>
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union overlay64 {
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u64 longw;
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struct {
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u32 lower;
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u32 higher;
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} words;
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};
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u64 __ashldi3(u64 num, unsigned int shift)
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{
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union overlay64 output;
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output.longw = num;
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if (shift >= 32) {
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output.words.higher = output.words.lower << (shift - 32);
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output.words.lower = 0;
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} else {
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if (!shift)
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return num;
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output.words.higher = (output.words.higher << shift) |
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(output.words.lower >> (32 - shift));
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output.words.lower = output.words.lower << shift;
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}
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return output.longw;
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}
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u64 __lshrdi3(u64 num, unsigned int shift)
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{
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union overlay64 output;
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output.longw = num;
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if (shift >= 32) {
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output.words.lower = output.words.higher >> (shift - 32);
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output.words.higher = 0;
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} else {
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if (!shift)
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return num;
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output.words.lower = output.words.lower >> shift |
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(output.words.higher << (32 - shift));
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output.words.higher = output.words.higher >> shift;
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}
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return output.longw;
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}
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#define MAX_32BIT_UINT ((((u64)1) << 32) - 1)
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static u64 _64bit_divide(u64 dividend, u64 divider, u64 *rem_p)
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{
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u64 result = 0;
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/*
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* If divider is zero - let the rest of the system care about the
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* exception.
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*/
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if (!divider)
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return 1 / (u32)divider;
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/* As an optimization, let's not use 64 bit division unless we must. */
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if (dividend <= MAX_32BIT_UINT) {
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if (divider > MAX_32BIT_UINT) {
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result = 0;
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if (rem_p)
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*rem_p = divider;
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} else {
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result = (u32)dividend / (u32)divider;
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if (rem_p)
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*rem_p = (u32)dividend % (u32)divider;
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}
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return result;
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}
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while (divider <= dividend) {
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u64 locald = divider;
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u64 limit = __lshrdi3(dividend, 1);
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int shifts = 0;
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while (locald <= limit) {
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shifts++;
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locald = locald + locald;
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}
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result |= __ashldi3(1, shifts);
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dividend -= locald;
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}
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if (rem_p)
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*rem_p = dividend;
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return result;
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}
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u64 __udivdi3(u64 num, u64 den)
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{
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return _64bit_divide(num, den, NULL);
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}
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u64 __umoddi3(u64 num, u64 den)
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{
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u64 v = 0;
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_64bit_divide(num, den, &v);
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return v;
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}
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