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.
149 lines
3.8 KiB
C
149 lines
3.8 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: 2023-10-15
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* Author: Aryadev Chavali
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* Description: Basic types and routines
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*/
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#ifndef BASE_H
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#define BASE_H
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#include <stdint.h>
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/* Basic macros for a variety of uses. Quite self explanatory. */
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#define ARR_SIZE(xs) (sizeof(xs) / sizeof(xs[0]))
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#define MAX(a, b) ((a) > (b) ? (a) : (b))
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#define MIN(a, b) ((a) > (b) ? (b) : (a))
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#define TERM_GREEN "\e[0;32m"
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#define TERM_YELLOW "\e[0;33m"
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#define TERM_RED "\e[0;31m"
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#define TERM_RESET "\e[0;0m"
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// Flags for program behaviour (usually related to printing)
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#ifndef VERBOSE
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#define VERBOSE 0
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#endif
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#ifndef PRINT_HEX
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#define PRINT_HEX 0
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#endif
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/* Ease of use aliases for numeric types */
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typedef uint8_t u8;
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typedef int8_t i8;
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typedef uint32_t u32;
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typedef int32_t i32;
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typedef uint64_t u64;
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typedef int64_t i64;
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typedef float f32;
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typedef double f64;
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typedef u8 byte;
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typedef i8 s_byte;
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typedef u32 hword;
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typedef i32 s_hword;
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typedef u64 word;
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typedef i64 s_word;
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/* Macros for the sizes of common base data types. */
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#define HWORD_SIZE sizeof(hword)
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#define SHWORD_SIZE sizeof(s_hword)
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#define WORD_SIZE sizeof(word)
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#define SWORD_SIZE sizeof(s_word)
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/** Union for all basic data types in the virtual machine.
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*/
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typedef union
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{
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byte as_byte;
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s_byte as_char;
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hword as_hword;
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s_hword as_int;
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word as_word;
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s_word as_long;
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} data_t;
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/** Enum of type tags for the data_t structure to provide context.
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*/
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typedef enum
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{
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DATA_TYPE_NIL = 0,
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DATA_TYPE_BYTE,
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DATA_TYPE_HWORD,
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DATA_TYPE_WORD,
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} data_type_t;
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/* Some macros for constructing data_t instances quickly. */
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#define DBYTE(BYTE) ((data_t){.as_byte = (BYTE)})
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#define DHWORD(HWORD) ((data_t){.as_hword = (HWORD)})
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#define DWORD(WORD) ((data_t){.as_word = (WORD)})
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/** Safely subtract SUB from W, where both are words (64 bit integers).
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*
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* In case of underflow (i.e. where W - SUB < 0) returns 0 instead of
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* the underflowed result.
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*/
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#define WORD_SAFE_SUB(W, SUB) ((W) > (SUB) ? ((W) - (SUB)) : 0)
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/** Return the Nth byte of WORD
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* N should range from 0 to 7 as there are 8 bytes in a word.
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*/
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#define WORD_NTH_BYTE(WORD, N) (((WORD) >> ((N) * 8)) & 0xFF)
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/** Return the Nth half word of WORD
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* N should range from 0 to 1 as there are 2 half words in a word
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*/
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#define WORD_NTH_HWORD(WORD, N) (((WORD) >> ((N) * 2)) & 0xFFFFFFFF)
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/** Convert a buffer of bytes to a half word
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* We assume the buffer of bytes are in virtual machine byte code
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* format (big endian) and that they are at least HWORD_SIZE in
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* size.
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*/
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hword convert_bytes_to_hword(byte *buffer);
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/** Convert a half word into a VM byte code format bytes (big endian)
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* @param h: Half word to convert
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* @param buffer: Buffer to store into. We assume the buffer has at
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* least HWORD_SIZE space.
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*/
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void convert_hword_to_bytes(hword h, byte *buffer);
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/** Convert a buffer of bytes to a word
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* We assume the buffer of bytes are in virtual machine byte code
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* format (big endian) and that they are at least WORD_SIZE in
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* size.
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*/
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word convert_bytes_to_word(byte *);
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/** Convert a word into a VM byte code format bytes (big endian)
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* @param w: Word to convert
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* @param buffer: Buffer to store into. We assume the buffer has at
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* least WORD_SIZE space.
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*/
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void convert_word_to_bytes(word w, byte *buffer);
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/** Convert a half word into bytecode format (little endian)
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*/
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hword hword_htobc(hword);
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/** Convert a half word in bytecode format (little endian) to host
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* format
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*/
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hword hword_bctoh(hword);
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/** Convert a word into bytecode format (little endian)
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*/
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word word_htobc(word);
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/** Convert a word in bytecode format (little endian) to host format
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*/
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word word_bctoh(word);
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#endif
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