diff options
Diffstat (limited to 'lib/base.h')
| -rw-r--r-- | lib/base.h | 73 |
1 files changed, 57 insertions, 16 deletions
@@ -15,6 +15,7 @@ #include <stdint.h> +/* Basic macros for a variety of uses. Quite self explanatory. */ #define ARR_SIZE(xs) (sizeof(xs) / sizeof(xs[0])) #define MAX(a, b) ((a) > (b) ? (a) : (b)) #define MIN(a, b) ((a) > (b) ? (b) : (a)) @@ -23,7 +24,7 @@ #define TERM_RED "\e[0;31m" #define TERM_RESET "\e[0;0m" -// Flags +// Flags for program behaviour (usually related to printing) #ifndef VERBOSE #define VERBOSE 0 #endif @@ -31,6 +32,7 @@ #define PRINT_HEX 0 #endif +/* Ease of use aliases for numeric types */ typedef uint8_t u8; typedef int8_t i8; typedef uint32_t u32; @@ -48,6 +50,14 @@ typedef i32 s_hword; typedef u64 word; typedef i64 s_word; +/* Macros for the sizes of common base data types. */ +#define HWORD_SIZE sizeof(hword) +#define SHWORD_SIZE sizeof(s_hword) +#define WORD_SIZE sizeof(word) +#define SWORD_SIZE sizeof(s_word) + +/** Union for all basic data types in the virtual machine. + */ typedef union { byte as_byte; @@ -58,6 +68,8 @@ typedef union s_word as_long; } data_t; +/** Enum of type tags for the data_t structure to provide context. + */ typedef enum { DATA_TYPE_NIL = 0, @@ -66,25 +78,54 @@ typedef enum DATA_TYPE_WORD, } data_type_t; -#define DBYTE(BYTE) ((data_t){.as_byte = (BYTE)}) -#define DHWORD(HWORD) ((data_t){.as_hword = (HWORD)}) -#define DWORD(WORD) ((data_t){.as_word = (WORD)}) +/* Some macros for constructing data_t instances quickly. */ +#define DBYTE(BYTE) ((data_t){.as_byte = (BYTE)}) +#define DHWORD(HWORD) ((data_t){.as_hword = (HWORD)}) +#define DWORD(WORD) ((data_t){.as_word = (WORD)}) + +/** Safely subtract SUB from W, where both are words (64 bit integers). + * + * In case of underflow (i.e. where W - SUB < 0) returns 0 instead of + * the underflowed result. + */ #define WORD_SAFE_SUB(W, SUB) ((W) > (SUB) ? ((W) - (SUB)) : 0) -#define HWORD_SIZE sizeof(hword) -#define SHWORD_SIZE sizeof(s_hword) -#define WORD_SIZE sizeof(word) -#define SWORD_SIZE sizeof(s_word) +/** Return the Nth byte of WORD + * N should range from 0 to 7 as there are 8 bytes in a word. + */ +#define WORD_NTH_BYTE(WORD, N) (((WORD) >> ((N) * 8)) & 0xFF) -// Macros to extract the nth byte or nth hword from a word -#define WORD_NTH_BYTE(WORD, N) (((WORD) >> ((N)*8)) & 0xFF) -#define WORD_NTH_HWORD(WORD, N) (((WORD) >> ((N)*2)) & 0xFFFFFFFF) +/** Return the Nth half word of WORD + * N should range from 0 to 1 as there are 2 half words in a word + */ +#define WORD_NTH_HWORD(WORD, N) (((WORD) >> ((N) * 2)) & 0xFFFFFFFF) + +/** Convert a buffer of bytes to a half word + * We assume the buffer of bytes are in virtual machine byte code + * format (big endian) and that they are at least HWORD_SIZE in + * size. + */ +hword convert_bytes_to_hword(byte *buffer); -// Assume array contains 4 bytes. -hword convert_bytes_to_hword(byte *); -void convert_hword_to_bytes(hword, byte *); -// Assume array contains 8 bytes. +/** Convert a half word into a VM byte code format bytes (big endian) + * @param h: Half word to convert + * @param buffer: Buffer to store into. We assume the buffer has at + * least HWORD_SIZE space. + */ +void convert_hword_to_bytes(hword h, byte *buffer); + +/** Convert a buffer of bytes to a word + * We assume the buffer of bytes are in virtual machine byte code + * format (big endian) and that they are at least WORD_SIZE in + * size. + */ word convert_bytes_to_word(byte *); -void convert_word_to_bytes(word, byte *); + +/** Convert a word into a VM byte code format bytes (big endian) + * @param w: Word to convert + * @param buffer: Buffer to store into. We assume the buffer has at + * least WORD_SIZE space. + */ +void convert_word_to_bytes(word w, byte *buffer); #endif |