2 Pass Bison Assembler

http://lists.gnu.org/archive/html/help-bison/2009-01/msg00001.html

the simplest assembler sasm cannot handle forward references. We can use single pass but it is too complicated. Inspired by articles such as the above, I attempted 2 pass.

Just add a global variable pass and repeat yyparse().

inside the code generator, if pass = 2, then do the code generation, otherwise just increment PC.

int pass=1;
yyparse();
pass=2;
yyparse;


Alternatively,
just repeat yyparse twice. You will get 2output. just discard the first one.

yyparse();
yyparse();