Aryadev Chavali
3b912495de
Instead of using endian.h that is not portable AND doesn't work with C++, I'll just write my own using a forced union based type punning trick. I've decided to use little endian for the format as well: it seems to be used by most desktop computers so it should make these functions faster to run for most CPUs.
108 lines
2.0 KiB
C
108 lines
2.0 KiB
C
/* Copyright (C) 2023 Aryadev Chavali
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* You may distribute and modify this code under the terms of the
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* GPLv2 license. You should have received a copy of the GPLv2
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* license with this file. If not, please write to:
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* aryadev@aryadevchavali.com.
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* Created: 2023-10-26
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* Author: Aryadev Chavali
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* Description: Implementation of basic library functions
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*/
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#include "./base.h"
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#include <string.h>
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union hword_pun
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{
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hword h;
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byte bytes[HWORD_SIZE];
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};
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union word_pun
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{
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word h;
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byte bytes[WORD_SIZE];
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};
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hword hword_htobc(hword w)
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{
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#if __LITTLE_ENDIAN__
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return w;
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#else
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union hword_pun x = {w};
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union hword_pun y = {0};
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for (size_t i = 0, j = HWORD_SIZE; i < HWORD_SIZE; ++i, --j)
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y.bytes[j - 1] = x.bytes[i];
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return y.h;
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#endif
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}
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hword hword_bctoh(hword w)
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{
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#if __LITTLE_ENDIAN__
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return w;
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#else
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union hword_pun x = {w};
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union hword_pun y = {0};
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for (size_t i = 0, j = HWORD_SIZE; i < HWORD_SIZE; ++i, --j)
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y.bytes[j - 1] = x.bytes[i];
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return y.h;
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#endif
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}
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word word_htobc(word w)
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{
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#if __LITTLE_ENDIAN__
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return w;
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#else
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union word_pun x = {w};
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union word_pun y = {0};
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for (size_t i = 0, j = WORD_SIZE; i < WORD_SIZE; ++i, --j)
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y.bytes[j - 1] = x.bytes[i];
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return y.h;
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#endif
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}
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word word_bctoh(word w)
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{
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#if __LITTLE_ENDIAN__
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return w;
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#else
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union word_pun x = {w};
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union word_pun y = {0};
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for (size_t i = 0, j = WORD_SIZE; i < WORD_SIZE; ++i, --j)
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y.bytes[j - 1] = x.bytes[i];
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return y.h;
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#endif
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}
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hword convert_bytes_to_hword(byte *bytes)
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{
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hword be_h = 0;
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memcpy(&be_h, bytes, HWORD_SIZE);
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hword h = hword_bctoh(be_h);
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return h;
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}
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void convert_hword_to_bytes(hword w, byte *bytes)
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{
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hword be_h = hword_htobc(w);
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memcpy(bytes, &be_h, HWORD_SIZE);
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}
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void convert_word_to_bytes(word w, byte *bytes)
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{
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word be_w = word_htobc(w);
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memcpy(bytes, &be_w, WORD_SIZE);
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}
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word convert_bytes_to_word(byte *bytes)
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{
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word be_w = 0;
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memcpy(&be_w, bytes, WORD_SIZE);
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word w = word_bctoh(be_w);
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return w;
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}
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