Implemented the symbolfile command (as mentioned by the help
command). This reads a symbol file in the format generated by nm.

diff --git a/debugger/dbg.y b/debugger/dbg.y
index 24e0f02..7362693 100644
--- a/debugger/dbg.y
+++ b/debugger/dbg.y
@@ -66,6 +66,7 @@
 %token <string> tIDENTIFIER tSTRING tDEBUGSTR
 %token <integer> tNUM tFORMAT
 %token <reg> tREG
+%token tSYMBOLFILE
 
 %token tCHAR tSHORT tINT tLONG tFLOAT tDOUBLE tUNSIGNED tSIGNED 
 %token tSTRUCT tUNION tENUM
@@ -156,6 +157,7 @@
     | tCOND tNUM tEOL          { DEBUG_AddBPCondition($2, NULL); }
     | tCOND tNUM expr tEOL     { DEBUG_AddBPCondition($2, $3); }
     | tDEBUGMSG tDEBUGSTR tEOL { MAIN_ParseDebugOptions($2); }
+    | tSYMBOLFILE pathname tEOL{ DEBUG_ReadSymbolTable($2); }
     | list_command
     | disassemble_command
     | set_command
diff --git a/debugger/debug.l b/debugger/debug.l
index fd31b35..e7b24c0 100644
--- a/debugger/debug.l
+++ b/debugger/debug.l
@@ -142,6 +142,7 @@
 
 <INITIAL>mode				{ BEGIN(NOCMD); return tMODE; }
 <INITIAL>show|sho|sh			{ BEGIN(SHOW_CMD); return tSHOW; }
+<INITIAL>symbolfile|symbols|symbol|sf   { BEGIN(PATH_EXPECTED); return tSYMBOLFILE; }
 
 <INITIAL,INFO_CMD,DEL_CMD>break|brea|bre|br|b	{ BEGIN(PATH_EXPECTED); return tBREAK; }