lc3.c File Reference

provided utility functions for LC3 assembler (do not modify) More...

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <strings.h>
#include <stdbool.h>
#include "lc3.h"
#include "util.h"

Functions
LC3_inst_t *	lc3_get_inst_info (opcode_t opcode)
inst_format_t *	lc3_get_inst_format (const char *name)
char *	lc3_get_suffix (char *file_name)
bool	lc3_file_has_suffix (const char *file_name, const char *suffix)
char *	lc3_replace_suffix (char *file_name, char *new_suffix)
void	lc3_set_obj_file_mode (const char *name)
int	lc3_read_LC3_word (FILE *f)
void	lc3_write_LC3_word (FILE *f, int val)
char	lc3_escaped_char (char c)
bool	lc3_get_address (sym_table_t *symTab, const char *addr, int *value)
void	lc3_read_sym_table (FILE *sym_file, sym_table_t *symTab)
static void	write_one_symbol (symbol_t *sym, void *data)
void	lc3_write_sym_table (FILE *sym_file, sym_table_t *symTab)
const char *	lc3_get_opcode_name (opcode_t op)
const char *	lc3_get_operand_name (operand_t operand)
const char *	lc3_get_format_name (format_t format)

Variables
static bool	inHex
static LC3_inst_t	lc3_instructions []

Detailed Description

This file implements the interface defined in lc3.h.

Author

Fritz Sieker

Function Documentation

char lc3_escaped_char

(

char

c

)

Convert an escape sequence to a single character

Parameters

c	the character after the escape character (the back-slash)

Returns

the ascaped value of the character

bool lc3_file_has_suffix	(	const char *	file_name,
		const char *	suffix
	)

Determine if file_name has the specified suffix

Parameters

file_name	- file name to check
suffix	- value to match

Returns

- true if suffix matches actual suffix of file_name

bool lc3_get_address	(	sym_table_t *	symTab,
		const char *	token,
		int *	value
	)

Convert a string to an address. The string is assumed to be a symbol. If it is found in the symbol table, the address is returned via the pointer. Otherwise call lc3_get_int() to convert the "number" to an address.

Parameters

symTab	- the file in which the symbol table is written
token	- the string to be converted
value	- pointer to where the address will be stored

Returns

true on success, false on failure

const char* lc3_get_format_name

(

format_t

format

)

Convert a format_t to a "name"

Parameters

format

- the value to convert (e.g. FMT_RRI5)

Returns

- a human readable name (e.g. "reg,reg,imm5" )

inst_format_t* lc3_get_inst_format

(

const char *

name

)

Get the format for an instructon given its name. The ADD/AND instructions have two forms with the same name and this routine will return the one with reg,reg,imm5.

Parameters

name	the opcode as a string (e.g. "AND")

Returns

a pointer to the format or NULL

LC3_inst_t* lc3_get_inst_info

(

opcode_t

opcode

)

Get the information for an instruction, given its opcode This is simply an access into an array of values initialized with the information for each of the LC3's sixteen instructions and additional pseudo-ops.

Parameters

opcode

- the opcode of the instruction/pseudo-op of interest

Returns

- a pointer to the syntax information for this instruction or NULL

const char* lc3_get_opcode_name

(

opcode_t

op

)

convert an opcode_t to a name

Parameters

op	- the opcode to convert (e.g. OP_ADD)

Returns

- a human readable name (e.g. "ADD")

const char* lc3_get_operand_name

(

operand_t

operand

)

convert operand type to a "name"

char* lc3_get_suffix

(

char *

file_name

)

Get the suffix of a file name

Parameters

file_name

- file name to check

Returns

- a pointer to the rightmost location of '.' in file_name or to the null byte at the end of file_name.

int lc3_read_LC3_word

(

FILE *

f

)

Read an LC3 word from a file (binary or hex - see lc3_set_obj_file_mode())

Parameters

f	- the object file

Returns

the value, or -1 on EOF

void lc3_read_sym_table	(	FILE *	sym_file,
		sym_table_t *	symTab
	)

Read the symbol table file and populate the global variable lc3_sym_tab. No error checking is performed. It is assumbed the file is in the correct format.

Parameters

sym_file	the file containing the symbol table
symTab	pointer to the symbol table

char* lc3_replace_suffix	(	char *	file_name,
		char *	new_suffix
	)

Create a new dynamically allocated string with the existing suffix (if any) replaced by a new suffix.

Parameters

file_name	- original file name
new_suffix	- replace existing suffix with this value

Returns

- the new string (must be free'd by caller)

void lc3_set_obj_file_mode

(

const char *

name

)

Set 'inHex' depending on the file suffix. lc3_read_LC3_word() and lc3_write_LC3_word() depend on 'inHex'

Parameters

name	- the name of the file

void lc3_write_LC3_word	(	FILE *	f,
		int	value
	)

Write an LC3 word to a file (binary or hex - See lc3_set_obj_file_mode())

Parameters

f	- the file to write to
value	- the value to write

void lc3_write_sym_table	(	FILE *	sym_file,
		sym_table_t *	symTab
	)

Write the symbol table to a file from the global variable lc3_sym_tab

Parameters

sym_file	- the file in which the symbol table is written
symTab	- pointer to the symbol table

static void write_one_symbol ( symbol_t *  sym, void *  data  )

static

callback function for symbol_interate()

Variable Documentation

bool inHex

static

Global flag defining whether using .obj file or .hex file. If false, each LC3 instruction is encoded in 16 bits. If true, each instruction is encoded by 4 hex digits followed by a newline.

LC3_inst_t lc3_instructions[]

static

A compact representation of the LC3 ISA plus pseudo-ops