symbol.h File Reference

#include <stdint.h>
#include <stdlib.h>

Go to the source code of this file.

Data Structures
struct	instruction_format_t
	Represents a valid instruction format. More...
struct	instruction_t
	Represents an instruction. More...
struct	label_t
	Represents a label. More...
struct	label_list_t
	Represents a list of labels. More...
struct	symbol_t
	Represents a symbol with a type, value, and line number. More...
struct	symbol_list_t
	Represents a symbol with a type, value, and line number. More...

Macros
#define	INSTRUCTION_COUNT   64
#define	LABEL_CEILING   64
#define	LABEL_IDENTIFIER_SIZE   20
#define	SYMBOL_CEILING   64
#define	S_CLS   "CLS"
#define	S_RET   "RET"
#define	S_JP   "JP"
#define	S_CALL   "CALL"
#define	S_SE   "SE"
#define	S_SNE   "SNE"
#define	S_LD   "LD"
#define	S_ADD   "ADD"
#define	S_OR   "OR"
#define	S_AND   "AND"
#define	S_SUB   "SUB"
#define	S_SHR   "SHR"
#define	S_SUBN   "SUBN"
#define	S_SHL   "SHL"
#define	S_RND   "RND"
#define	S_DRW   "DRW"
#define	S_SKP   "SKP"
#define	S_SKNP   "SKNP"
#define	S_XOR   "XOR"
#define	S_SCD   "SCD"
#define	S_SCR   "SCR"
#define	S_SCL   "SCL"
#define	S_EXIT   "EXIT"
#define	S_LOW   "LOW"
#define	S_HIGH   "HIGH"
#define	S_JP_V0   "JP V0,"
#define	S_K   "K"
#define	S_F   "F"
#define	S_B   "B"
#define	S_DT   "DT"
#define	S_ST   "ST"
#define	S_I   "I"
#define	S_IP   "[I]"
#define	S_DB   ".DB"
#define	S_DW   ".DW"
#define	S_DS   ".DS"
#define	S_HF   "HF"
#define	S_R   "R"

Enumerations
enum	Instruction {   I_NULL = -1 , I_CLS , I_RET , I_JP ,   I_CALL , I_SE , I_SNE , I_LD ,   I_ADD , I_OR , I_AND , I_SUB ,   I_SHR , I_SUBN , I_SHL , I_RND ,   I_DRW , I_SKP , I_SKNP , I_XOR ,   I_SCD , I_SCR , I_SCL , I_EXIT ,   I_LOW , I_HIGH , I_JP_V0 }
	Represents instruction types. More...
enum	Symbol {   SYM_NULL , SYM_DT , SYM_ST , SYM_I ,   SYM_IP , SYM_K , SYM_F , SYM_B ,   SYM_DB , SYM_DW , SYM_DS , SYM_HF ,   SYM_R , SYM_LABEL , SYM_INT , SYM_INT4 ,   SYM_INT8 , SYM_INT12 , SYM_STRING , SYM_V ,   SYM_INSTRUCTION , SYM_LABEL_DEFINITION }
	Represents symbol types. More...

Functions
int	build_instruction (instruction_t *, symbol_list_t *, int)
	Build an instruction from symbols beginning at idx.
int	is_comment (const char *)
	Check if the given string is a comment.
int	is_db (const char *)
	Check if given string is a DB identifier.
int	is_ds (const char *)
	Check if given string is a DS identifier.
int	is_dw (const char *)
	Check if given string is a DW identifier.
int	is_instruction (const char *)
	Check if the given string is an instruction.
int	is_label_definition (const char *)
	Check if the given string is a label definition.
int	is_label (const char *, const label_list_t *)
	Check if given string is a label reference.
int	is_register (const char *)
	Check if the given string represents a V register.
int	is_reserved_identifier (const char *)
	Check if given string is a reserved identifier.
symbol_t *	next_symbol (symbol_list_t *)
	Get the next symbol.
int	populate_labels (label_list_t *)
	Populate label list from lines.
int	resolve_labels (symbol_list_t *, label_list_t *)
	Get byte indexes of label definitions from completed symbol table.
int	shift (uint16_t)
	Find the bits needed to shift to OR a parameter into an instruction.
int	substitute_labels (symbol_list_t *, label_list_t *)
	Substitute label symbols with their corresponding int value.

Variables
const char *	c8_instructionStrings []
const char *	c8_identifierStrings []
instruction_format_t	formats []

Detailed Description

Note

NOT EXPORTED

Stuff for parsing symbols and instructions for encoding CHIP-8 "assembly".

Macro Definition Documentation

INSTRUCTION_COUNT

#define INSTRUCTION_COUNT   64

LABEL_CEILING

#define LABEL_CEILING   64

LABEL_IDENTIFIER_SIZE

#define LABEL_IDENTIFIER_SIZE   20

S_ADD

#define S_ADD   "ADD"

S_AND

#define S_AND   "AND"

S_B

#define S_B   "B"

S_CALL

#define S_CALL   "CALL"

S_CLS

#define S_CLS   "CLS"

S_DB

#define S_DB   ".DB"

S_DRW

#define S_DRW   "DRW"

S_DS

#define S_DS   ".DS"

S_DT

#define S_DT   "DT"

S_DW

#define S_DW   ".DW"

S_EXIT

#define S_EXIT   "EXIT"

S_F

#define S_F   "F"

S_HF

#define S_HF   "HF"

S_HIGH

#define S_HIGH   "HIGH"

S_I

#define S_I   "I"

S_IP

#define S_IP   "[I]"

S_JP

#define S_JP   "JP"

S_JP_V0

#define S_JP_V0   "JP V0,"

S_K

#define S_K   "K"

S_LD

#define S_LD   "LD"

S_LOW

#define S_LOW   "LOW"

S_OR

#define S_OR   "OR"

S_R

#define S_R   "R"

S_RET

#define S_RET   "RET"

S_RND

#define S_RND   "RND"

S_SCD

#define S_SCD   "SCD"

S_SCL

#define S_SCL   "SCL"

S_SCR

#define S_SCR   "SCR"

S_SE

#define S_SE   "SE"

S_SHL

#define S_SHL   "SHL"

S_SHR

#define S_SHR   "SHR"

S_SKNP

#define S_SKNP   "SKNP"

S_SKP

#define S_SKP   "SKP"

S_SNE

#define S_SNE   "SNE"

S_ST

#define S_ST   "ST"

S_SUB

#define S_SUB   "SUB"

S_SUBN

#define S_SUBN   "SUBN"

S_XOR

#define S_XOR   "XOR"

SYMBOL_CEILING

#define SYMBOL_CEILING   64

Enumeration Type Documentation

Instruction

enum Instruction

Represents instruction types.

This enumeration defines all possible CHIP-8 instructions.

NOTE: values to be kept in same order as instructionStrings

Enumerator
I_NULL
I_CLS
I_RET
I_JP
I_CALL
I_SE
I_SNE
I_LD
I_ADD
I_OR
I_AND
I_SUB
I_SHR
I_SUBN
I_SHL
I_RND
I_DRW
I_SKP
I_SKNP
I_XOR
I_SCD
I_SCR
I_SCL
I_EXIT
I_LOW
I_HIGH
I_JP_V0

Symbol

enum Symbol

Represents symbol types.

This enumeration defines all symbol types found during the first assembler pass.

NOTE: values before label need to be kept in same order as identifierStrings

Enumerator
SYM_NULL
SYM_DT
SYM_ST
SYM_I
SYM_IP
SYM_K
SYM_F
SYM_B
SYM_DB
SYM_DW
SYM_DS
SYM_HF
SYM_R
SYM_LABEL
SYM_INT
SYM_INT4
SYM_INT8
SYM_INT12
SYM_STRING
SYM_V
SYM_INSTRUCTION
SYM_LABEL_DEFINITION

Function Documentation

build_instruction()

int build_instruction	(	instruction_t *	ins,
		symbol_list_t *	symbols,
		int	idx
	)

Build an instruction from symbols beginning at idx.

This function builds an instruction from a completely parsed set of symbols (with labels expanded).

Parameters

ins	instruction_t to store instruction contents
symbols	symbol list
idx	symbols index of start of instruction

Returns

instruction bytecode

is_comment()

int is_comment

(

const char *

s

)

Check if the given string is a comment.

Parameters

s	the string to check

Returns

1 if true, 0 if false

is_db()

int is_db

(

const char *

s

)

Check if given string is a DB identifier.

Returns

1 if true, 0 if false

is_ds()

int is_ds

(

const char *

s

)

Check if given string is a DS identifier.

Returns

1 if true, 0 if false

is_dw()

int is_dw

(

const char *

s

)

Check if given string is a DW identifier.

Returns

1 if true, 0 if false

is_instruction()

int is_instruction

(

const char *

s

)

Check if the given string is an instruction.

Parameters

s	the string to check

Returns

instruction enumerator if true, -1 if false

is_label()

int is_label	(	const char *	s,
		const label_list_t *	labels
	)

Check if given string is a label reference.

This function checks if the given string is a label reference by comparing it against the label list. It returns the index of the label in the label list if it is found, or -1 if it is not.

This function assumes that the label list has been populated (e.g. populate_labels() has been called).

Parameters

s	string to check
labels	label list to check from

Returns

label index if true, -1 otherwise

is_label_definition()

int is_label_definition

(

const char *

s

)

Check if the given string is a label definition.

Parameters

s	the string to check

Returns

1 if true, 0 if false

is_register()

int is_register

(

const char *

s

)

Check if the given string represents a V register.

This function checks if the given string starts with 'V' or 'v' and is followed by a valid hexadecimal digit (0-9, A-F, a-f). It returns the register number if it is a valid V register, or -1 if it is not.

Parameters

s	string to check

Returns

V register number if true, -1 otherwise

is_reserved_identifier()

int is_reserved_identifier

(

const char *

s

)

Check if given string is a reserved identifier.

This function checks if the given string is one of the reserved identifiers defined in c8_identifierStrings. It returns the index of the identifier if it is found, or -1 if it is not.

Parameters

s	string to check

Returns

type of identifier if true, -1 otherwise

next_symbol()

symbol_t * next_symbol

(

symbol_list_t *

symbols

)

Get the next symbol.

This function retrieves the next available symbol in the symbol list. If the symbol list is empty, it initializes the first symbol. If the symbol list is full, it reallocates the symbol list to accommodate more symbols.

If symbols is NULL or the symbol list is NULL, it returns NULL.

Parameters

symbols

symbol list to get next symbol from

Returns

first empty symbol in symbol table

populate_labels()

int populate_labels

(

label_list_t *

labels

)

Populate label list from lines.

This function scans through the lines of code and identifies label definitions. It checks each line for a label definition (ending with a colon) and adds it to the label list.

If a duplicate label definition is found, it throws a DUPLICATE_LABEL_EXCEPTION.

If too many labels are defined, it throws a TOO_MANY_LABELS_EXCEPTION.

Parameters

lines	lines to search
lineCount	number of lines to search
labels	label list to populate

Returns

1 if success, 0 if failure

resolve_labels()

int resolve_labels	(	symbol_list_t *	symbols,
		label_list_t *	labels
	)

Get byte indexes of label definitions from completed symbol table.

This function resolves label definitions in the symbol list and populates the label list with the byte index of each label definition. It iterates through the symbols, keeping track of the current byte position in the program. When it encounters a label definition, it records the current byte position in the label list. It also increments the byte position based on the type of symbol encountered (e.g., SYM_DB increments by 1, SYM_INSTRUCTION and SYM_DW increment by 2).

This function assumes that the symbol list has been populated and that the symbols have been parsed correctly. It also assumes that the label list has been initialized.

This function will return 1 if all labels were resolved successfully, or 0 if there was a failure (e.g., if the label list is not fully populated).

This function will throw a NULL_ARGUMENT_EXCEPTION if either symbols or labels is NULL.

Parameters

symbols	list of symbols
labels	list of labels

Returns

1 if success, 0 if failure

shift()

int shift

(

uint16_t

fmt

)

Find the bits needed to shift to OR a parameter into an instruction.

This function finds the bits needed to shift to OR a parameter into an instruction. It is used to determine the position of parameters in the instruction bytecode.

This is a workaround for the fact that the instruction formats are not defined in a way that allows for easy bit manipulation.

Parameters

fmt	instruction_format_t pformat to check

Returns

number of bits to shift

substitute_labels()

int substitute_labels	(	symbol_list_t *	symbols,
		label_list_t *	labels
	)

Substitute label symbols with their corresponding int value.

This function replaces all symbols of type SYM_LABEL in the symbol list with their corresponding byte value from the label list. It checks if the label exists and throws an INVALID_SYMBOL_EXCEPTION if it does not.

This function assumes that the label list has been populated and that their byte values have been set correctly.

Parameters

symbols	symbols to search
labels	labels to search

Variable Documentation

c8_identifierStrings

const char* c8_identifierStrings[]

extern

Reserved identifier strings. Has to match Symbol.

c8_instructionStrings

const char* c8_instructionStrings[]

extern

Instruction strings. Has to match Instruction.

formats

instruction_format_t formats[]

extern

All valid instruction formats