$/*$

$*********************************************$

$*$ Principles of Programming Languages $*$

$*$ Fall $2024*$

$*$ Authors: Sheryl D'Mello $*$

$*********************************************$

$*/$

$/*-------------------------------------------------$

CFG for tinyL LANGUAGE

::$=!$

::$=$

::$=$ ; $|$

::$=||$

::$==$

::$=?$

::$=\%$

::$=+|$

$|$

$|$

& $|$

$||$

$|$

::$=$ a $|$ b $|$ c $|$ d $|$ e $|$ f

::$=0|1|2|3|4|5|6|7|8|9$

NOTE: tokens are exactly a single character long

Example expressions:

a$=+2+25$;$\%$a$!$

a$=|2$&$3|25$;$\%$a$!$

$---------------------------------------------------$

$*/$

#include

#include

#include

#include "Instr.h$"$

#include "InstrUtils.h$"$

#include "Utils.h$"$

#define MAX$\_$BUFFER$\_$SIZE $500$

#define EMPTY$\_$FIELD $0$xFFFFF

#define token $*$buffer

$/*$ GLOBALS $*/$

static char $*$buffer $=$ NULL; $/*$ read buffer $*/$

static int regnum $=1$; $/*$ for next free virtual register number $*/$

static FILE $*$outfile $=$ NULL; $/*$ output of code generation $*/$

$/*$ Utilities $*/$

static void CodeGen$($OpCode opcode, int field$1,$ int field$2,$ int field$3)$;

static inline void next$\_$token$()$;

static inline int next$\_$register$()$;

static inline int is$\_$digit$($char c$)$;

static inline int to$\_$digit$($char c$)$;

static inline int is$\_$identifier$($char c$)$;

static char $*$read$\_$input$($FILE $*$ f$)$;

$/*$ Routines for recursive descending parser LL$(1)*/$

static void program$()$;

static void stmtlist$()$;

static void morestmts$()$;

static void stmt$()$;

static void assign$()$;

static void read$()$;

static void print$()$;

static int expr$()$;

static int variable$()$;

static int digit$()$;

$/*************************************************************************/$

$/*$ Definitions for recursive descending parser LL$(1)*/$

$/*************************************************************************/$

static int digit$()$

$\{$

int reg;

if $(!$is$\_$digit$($token$))$

$\{$

ERROR$("$Expected digit

$")$;

exit$($EXIT$\_$FAILURE$)$;

$\}$

reg $=$ next$\_$register$()$;

CodeGen$($LOADI$,$ reg, to$\_$digit$($token$),$ EMPTY$\_$FIELD$)$;

next$\_$token$()$;

return reg;

$\}$

static int variable$()$

$\{$

$/*$ YOUR CODE GOES HERE $*/$

int reg;

if $(!$is$\_$identifier$($token$))$

$\{$

ERROR$("$Expected variable

$")$;

exit$($EXIT$\_$FAILURE$)$;

$\}$

reg $=$ next$\_$register$()$;

CodeGen$($LOAD$,$ reg, token, EMPTY$\_$FIELD$)$;

next$\_$token$()$;

return reg;

$\}$

static int expr$()$