view lwasm/pass3.c @ 408:0af33282b518

Fix cycle counting for relative branches. The original creator of the cycle counting code appears to have mangled two different approaches to counting the cycles for relative branches into the final product which led to counting too many cycles for the branch instructions. The comments in the cycle table were correct but the code was doing some incorrect things. Also add the missing LBRN entry to the cycle table. The one labelled LBRN was not, in fact, LBRN, but one of the actual useful branch instructions.
author William Astle <lost@l-w.ca>
date Thu, 03 Mar 2016 21:38:21 -0700
parents 697bc543368c
children
line wrap: on
line source

/*
pass3.c

Copyright © 2010 William Astle

This file is part of LWTOOLS.

LWTOOLS is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.

You should have received a copy of the GNU General Public License along with
this program. If not, see <http://www.gnu.org/licenses/>.
*/

#include <stdio.h>
#include <string.h>

#include <lw_alloc.h>
#include <lw_string.h>

#include "lwasm.h"
#include "instab.h"

/*
Resolve1 Pass

repeatedly resolve instruction sizes and line addresses
until nothing more reduces

*/
void do_pass3(asmstate_t *as)
{
	int rc;
	line_t *cl;
	struct line_expr_s *le;
	
	do
	{
		rc = 0;
		for (cl = as -> line_head; cl; cl = cl -> next)
		{
			as -> cl = cl;
			
			// simplify address
			lwasm_reduce_expr(as, cl -> addr);
		
			// simplify data address
			lwasm_reduce_expr(as, cl -> daddr);

			// simplify each expression
			for (le = cl -> exprs; le; le = le -> next)
				lwasm_reduce_expr(as, le -> expr);
			
			if (cl -> len == -1 || cl -> dlen == -1)
			{
				// try resolving the instruction length
				// but don't force resolution
				if (cl -> insn >= 0 && instab[cl -> insn].resolve)
				{
					(instab[cl -> insn].resolve)(as, cl, 0);
					debug_message(as, 100, "len = %d, dlen = %d", cl -> len, cl -> dlen);
					if ((cl -> inmod == 0) && cl -> len >= 0 && cl -> dlen >= 0)
					{
						if (cl -> len == 0)
							cl -> len = cl -> dlen;
						else
							cl -> dlen = cl -> len;
					}
					if (cl -> len != -1 && cl -> dlen != -1)
						rc++;
				}
			}
		}
		if (as -> errorcount > 0)
			return;
	} while (rc > 0);
}