Mercurial > hg > index.cgi
view lwasm/pass4.c @ 505:59b8c8b15bd4
Add integer shifts and fix code template errors for mul/div/mod
One needs to remove stuff from the stack after putting it there. Actually do
that in the code output for multiplication, division, and modulus.
Add integer shifting code output which is optimized for constant shift
counts but calls a routine for non-constant shift counts. Shifting by a
negative amount is a no-op. Shifting by more than the size of an integer
results in 0 (for left shifts) or -1 (for right shifts). Both negative shift
counts and shift counts larger than the base type are undefined in the C
standard so this behaviour is allowed.
author | William Astle <lost@l-w.ca> |
---|---|
date | Sat, 26 Oct 2019 22:01:55 -0600 |
parents | 8764142b3192 |
children |
line wrap: on
line source
/* pass4.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" /* Resolve2 Pass Force resolution of instruction sizes. */ void do_pass4_aux(asmstate_t *as, int force) { int rc; int cnt; line_t *cl, *sl; struct line_expr_s *le; int trycount = 0; // first, count the number of unresolved instructions for (cnt = 0, cl = as -> line_head; cl; cl = cl -> next) { if (cl -> len == -1) cnt++; } sl = as -> line_head; while (cnt > 0) { trycount = cnt; debug_message(as, 60, "%d unresolved instructions", cnt); // find an unresolved instruction for ( ; sl && sl -> len != -1; sl = sl -> next) { debug_message(as, 200, "Search line %p", sl); as -> cl = sl; lwasm_reduce_expr(as, sl -> addr); lwasm_reduce_expr(as, sl -> daddr); // simplify each expression for (le = sl -> exprs; le; le = le -> next) lwasm_reduce_expr(as, le -> expr); } debug_message(as, 200, "Found line %p", sl); // simplify address as -> cl = sl; lwasm_reduce_expr(as, sl -> addr); lwasm_reduce_expr(as, sl -> daddr); // simplify each expression for (le = sl -> exprs; le; le = le -> next) lwasm_reduce_expr(as, le -> expr); if (sl -> len == -1 && sl -> insn >= 0 && instab[sl -> insn].resolve) { (instab[sl -> insn].resolve)(as, sl, 1); debug_message(as, 200, "Try resolve = %d/%d", sl -> len, sl -> dlen); if (force && sl -> len == -1 && sl -> dlen == -1) { lwasm_register_error(as, sl, E_INSTRUCTION_FAILED); return; } } if (sl -> len != -1 && sl -> dlen != -1) { cnt--; if (cnt == 0) return; // this one resolved - try looking for the next one instead // of wasting time running through the rest of the lines continue; } do { debug_message(as, 200, "Flatten after..."); rc = 0; for (cl = sl; cl; cl = cl -> next) { debug_message(as, 200, "Flatten line %p", cl); as -> cl = cl; // simplify address lwasm_reduce_expr(as, cl -> addr); 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) { // 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); if ((cl -> inmod == 0) && cl -> len >= 0 && cl -> dlen >= 0) { if (cl -> len == 0) cl -> len = cl -> dlen; else cl -> dlen = cl -> len; } debug_message(as, 200, "Flatten resolve returns %d", cl -> len); if (cl -> len != -1 && cl -> dlen != -1) { rc++; cnt--; if (cnt == 0) return; } } } } if (as -> errorcount > 0) return; } while (rc > 0); if (trycount == cnt) break; } } void do_pass4(asmstate_t *as) { do_pass4_aux(as, 1); }