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view lwasm/insn_indexed.c @ 434:052c5f335a92
Fix bug in like terms collection in expression simplification
Like term collection would lose the actual "variable" part of the term if
the second term collected happened to have no coefficient. This would cause
the expression to take the value of the calculated coefficient which is
obviously wrong.
Thanks to hider <stego@satx.rr.com> for reporting the bug and providing a
proper test case.
Observation: this bug has been present since the first pre-release of
lwtools 3.0 when the algebraic expression system was introduced. Apparently
people tend not to create expressions that trigger the like terms handler.
The specific conditions require the symbol to be undefined and the second
operand to the addition has to have no coefficient so it's likely a fairly
rare scenario. Still, it is somewhat surprising that nobody tripped on it
before now.
author | William Astle <lost@l-w.ca> |
---|---|
date | Mon, 23 Jan 2017 22:58:36 -0700 |
parents | b20f14edda5a |
children | cad5937314cb |
line wrap: on
line source
/* insn_indexed.c Copyright © 2009 William Astle This file is part of LWASM. LWASM 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/>. */ /* for handling indexed mode instructions */ #include <ctype.h> #include <string.h> #include <lw_expr.h> #include "lwasm.h" #include "instab.h" /* l -> lint: size of operand (0, 1, 2, -1 if not determined) l -> pb: actual post byte (from "resolve" stage) or info passed forward to the resolve stage (if l -> line is -1); 0x80 is indir bits 0-2 are register number */ void insn_parse_indexed_aux(asmstate_t *as, line_t *l, char **p) { static const char *regs9 = "X Y U S PCRPC "; static const char *regs = "X Y U S W PCRPC "; int i, rn; int indir = 0; int f0 = 0; const char *reglist; lw_expr_t e; char *tstr; if (CURPRAGMA(l, PRAGMA_6809)) { reglist = regs9; } else { reglist = regs; } // is it indirect? if (**p == '[') { indir = 1; (*p)++; } lwasm_skip_to_next_token(l, p); if (**p == ',') { int incdec = 0; /* we have a pre-dec, post-inc, or no offset mode here */ (*p)++; lwasm_skip_to_next_token(l, p); if (**p == '-') { incdec = -1; (*p)++; if (**p == '-') { incdec = -2; (*p)++; } lwasm_skip_to_next_token(l, p); } /* allowed registers: X, Y, U, S, or W (6309) */ switch (**p) { case 'x': case 'X': rn = 0; break; case 'y': case 'Y': rn = 1; break; case 'u': case 'U': rn = 2; break; case 's': case 'S': rn = 3; break; case 'w': case 'W': if (CURPRAGMA(l, PRAGMA_6809)) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } rn = 4; break; default: lwasm_register_error(as, l, E_OPERAND_BAD); return; } (*p)++; lwasm_skip_to_next_token(l, p); if (**p == '+') { if (incdec != 0) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } incdec = 1; (*p)++; if (**p == '+') { incdec = 2; (*p)++; } lwasm_skip_to_next_token(l, p); } if (indir) { if (**p != ']') { lwasm_register_error(as, l, E_OPERAND_BAD); return; } (*p)++; } if (indir || rn == 4) { if (incdec == 1 || incdec == -1) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } } if (rn == 4) { if (indir) { if (incdec == 0) i = 0x90; else if (incdec == -2) i = 0xF0; else i = 0xD0; } else { if (incdec == 0) i = 0x8F; else if (incdec == -2) i = 0xEF; else i = 0xCF; } } else { switch (incdec) { case 0: i = 0x84; break; case 1: i = 0x80; break; case 2: i = 0x81; break; case -1: i = 0x82; break; case -2: i = 0x83; break; } i = (rn << 5) | i | (indir << 4); } l -> pb = i; l -> lint = 0; return; } i = toupper(**p); if ( (i == 'A' || i == 'B' || i == 'D') || (!CURPRAGMA(l, PRAGMA_6809) && (i == 'E' || i == 'F' || i == 'W')) ) { tstr = *p + 1; lwasm_skip_to_next_token(l, &tstr); if (*tstr == ',') { *p = tstr + 1; lwasm_skip_to_next_token(l, p); switch (**p) { case 'x': case 'X': rn = 0; break; case 'y': case 'Y': rn = 1; break; case 'u': case 'U': rn = 2; break; case 's': case 'S': rn = 3; break; default: lwasm_register_error(as, l, E_OPERAND_BAD); return; } (*p)++; lwasm_skip_to_next_token(l, p); if (indir) { if (**p != ']') { lwasm_register_error(as, l, E_OPERAND_BAD); return; } (*p)++; } switch (i) { case 'A': i = 0x86; break; case 'B': i = 0x85; break; case 'D': i = 0x8B; break; case 'E': i = 0x87; break; case 'F': i = 0x8A; break; case 'W': i = 0x8E; break; } l -> pb = i | (indir << 4) | (rn << 5); l -> lint = 0; return; } } /* we have the "expression" types now */ if (**p == '<') { l -> lint = 1; (*p)++; } else if (**p == '>') { l -> lint = 2; (*p)++; } lwasm_skip_to_next_token(l, p); if (**p == '0') { tstr = *p + 1; lwasm_skip_to_next_token(l, &tstr); if (*tstr == ',') { f0 = 1; } } // now we have to evaluate the expression e = lwasm_parse_expr(as, p); if (!e) { lwasm_register_error(as, l, E_OPERAND_BAD); return; } lwasm_save_expr(l, 0, e); if (**p != ',') { /* if no comma, we have extended indirect */ if (l -> lint == 1 || **p != ']') { lwasm_register_error(as, l, E_OPERAND_BAD); return; } (*p)++; l -> lint = 2; l -> pb = 0x9F; return; } (*p)++; lwasm_skip_to_next_token(l, p); // now get the register rn = lwasm_lookupreg3(reglist, p); if (rn < 0) { lwasm_register_error(as, l, E_REGISTER_BAD); return; } if (indir) { if (**p != ']') { lwasm_register_error(as, l, E_OPERAND_BAD); return; } else (*p)++; } if (rn <= 3) { // X,Y,U,S if (l -> lint == 1) { l -> pb = 0x88 | (rn << 5) | (indir ? 0x10 : 0); return; } else if (l -> lint == 2) { l -> pb = 0x89 | (rn << 5) | (indir ? 0x10 : 0); return; } } // nnnn,W is only 16 bit (or 0 bit) if (rn == 4) { if (l -> lint == 1) { lwasm_register_error(as, l, E_NW_8); return; } if (l -> lint == 2) { l -> pb = indir ? 0xb0 : 0xaf; l -> lint = 2; return; } l -> pb = (0x80 * indir) | rn; /* [,w] and ,w if (indir) *b1 = 0x90; else *b1 = 0x8f; */ return; } // PCR? then we have PC relative addressing (like B??, LB??) if (rn == 5 || (rn == 6 && CURPRAGMA(l, PRAGMA_PCASPCR))) { lw_expr_t e1, e2; // external references are handled exactly the same as for // relative addressing modes // on pass 1, adjust the expression for a subtraction of the // current address // e - (addr + linelen) => e - addr - linelen e2 = lw_expr_build(lw_expr_type_special, lwasm_expr_linelen, l); e1 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_minus, e, e2); lw_expr_destroy(e2); e2 = lw_expr_build(lw_expr_type_oper, lw_expr_oper_minus, e1, l -> addr); lw_expr_destroy(e1); lwasm_save_expr(l, 0, e2); if (l -> lint == 1) { l -> pb = indir ? 0x9C : 0x8C; return; } if (l -> lint == 2) { l -> pb = indir ? 0x9D : 0x8D; return; } } if (rn == 6) { if (l -> lint == 1) { l -> pb = indir ? 0x9C : 0x8C; return; } if (l -> lint == 2) { l -> pb = indir ? 0x9D : 0x8D; return; } } l -> pb = (indir * 0x80) | rn | (f0 * 0x40); } PARSEFUNC(insn_parse_indexed) { l -> lint = -1; insn_parse_indexed_aux(as, l, p); if (l -> lint != -1) { l -> len = OPLEN(instab[l -> insn].ops[0]) + l -> lint + 1; } } void insn_resolve_indexed_aux(asmstate_t *as, line_t *l, int force, int elen) { // here, we have an expression which needs to be // resolved; the post byte is determined here as well lw_expr_t e, e2; int pb = -1; int v; if (l -> len != -1) return; e = lwasm_fetch_expr(l, 0); if (!lw_expr_istype(e, lw_expr_type_int)) { // temporarily set the instruction length to see if we get a // constant for our expression; if so, we can select an instruction // size e2 = lw_expr_copy(e); // magic 2 for 8 bit (post byte + offset) l -> len = OPLEN(instab[l -> insn].ops[0]) + elen + 2; lwasm_reduce_expr(as, e2); // l -> len += 1; // e3 = lw_expr_copy(e); // lwasm_reduce_expr(as, e3); l -> len = -1; if (lw_expr_istype(e2, lw_expr_type_int)) { v = lw_expr_intval(e2); // we have a reducible expression here which depends on // the size of this instruction if (v == 0 && !CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) && (l -> pb & 0x07) <= 4) { if ((l -> pb & 0x07) < 4) { pb = 0x84 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0); } else { pb = (l -> pb & 0x80) ? 0x90 : 0x8F; } l -> pb = pb; lw_expr_destroy(e2); l -> lint = 0; return; } else if (v < -128 || v > 127) { l -> lint = 2; switch (l -> pb & 0x07) { case 0: case 1: case 2: case 3: pb = 0x89 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0); break; case 4: // W pb = (l -> pb & 0x80) ? 0xB0 : 0xAF; break; case 5: // PCR case 6: // PC pb = (l -> pb & 0x80) ? 0x9D : 0x8D; break; } l -> pb = pb; lw_expr_destroy(e2); // lw_expr_destroy(e3); return; } else if ((l -> pb & 0x80) || ((l -> pb & 0x07) > 3) || v < -16 || v > 15) { // if not a 5 bit value, is indirect, or is not X,Y,U,S l -> lint = 1; switch (l -> pb & 0x07) { case 0: case 1: case 2: case 3: pb = 0x88 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0); break; case 4: // W // use 16 bit because W doesn't have 8 bit, unless 0 if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40)) { pb = (l -> pb & 0x80) ? 0x90 : 0x8F; l -> lint = 0; } else { pb = (l -> pb & 0x80) ? 0xB0 : 0xAF; l -> lint = 2; } break; case 5: // PCR case 6: // PC pb = (l -> pb & 0x80) ? 0x9C : 0x8C; break; } l -> pb = pb; lw_expr_destroy(e2); return; } else { // we have X,Y,U,S and a possible 5 bit here l -> lint = 0; if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40)) { pb = (l -> pb & 0x03) << 5 | 0x84; } else { pb = ((l -> pb & 0x03) << 5) | (v & 0x1F); } l -> pb = pb; lw_expr_destroy(e2); return; } } lw_expr_destroy(e2); } if (lw_expr_istype(e, lw_expr_type_int)) { // we know how big it is v = lw_expr_intval(e); if (v == 0 && !CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) && (l -> pb & 0x07) <= 4 && ((l -> pb & 0x40) == 0)) { if ((l -> pb & 0x07) < 4) { pb = 0x84 | ((l -> pb & 0x03) << 5) | ((l -> pb & 0x80) ? 0x10 : 0); } else { pb = (l -> pb & 0x80) ? 0x90 : 0x8F; } l -> pb = pb; l -> lint = 0; return; } else if (v < -128 || v > 127) { do16bit: l -> lint = 2; switch (l -> pb & 0x07) { case 0: case 1: case 2: case 3: pb = 0x89 | (l -> pb & 0x03) << 5 | ((l -> pb & 0x80) ? 0x10 : 0); break; case 4: // W pb = (l -> pb & 0x80) ? 0xB0 : 0xAF; break; case 5: // PCR case 6: // PC pb = (l -> pb & 0x80) ? 0x9D : 0x8D; break; } l -> pb = pb; return; } else if ((l -> pb & 0x80) || ((l -> pb & 0x07) > 3) || v < -16 || v > 15) { // if not a 5 bit value, is indirect, or is not X,Y,U,S l -> lint = 1; switch (l -> pb & 0x07) { case 0: case 1: case 2: case 3: pb = 0x88 | (l -> pb & 0x03) << 5 | ((l -> pb & 0x80) ? 0x10 : 0); break; case 4: // W // use 16 bit because W doesn't have 8 bit, unless 0 if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40)) { pb = (l -> pb & 0x80) ? 0x90 : 0x8F; l -> lint = 0; } else { pb = (l -> pb & 0x80) ? 0xB0 : 0xAF; l -> lint = 2; } break; case 5: // PCR case 6: // PC pb = (l -> pb & 0x80) ? 0x9C : 0x8C; break; } l -> pb = pb; return; } else { // we have X,Y,U,S and a possible 5 bit here l -> lint = 0; if (v == 0 && !(CURPRAGMA(l, PRAGMA_NOINDEX0TONONE) || l -> pb & 0x40)) { pb = (l -> pb & 0x03) << 5 | 0x84; } else { pb = ((l -> pb & 0x03) << 5) | (v & 0x1F); } l -> pb = pb; return; } } else { // we don't know how big it is if (!force) return; // force 16 bit if we don't know l -> lint = 2; goto do16bit; } } RESOLVEFUNC(insn_resolve_indexed) { if (l -> lint == -1) insn_resolve_indexed_aux(as, l, force, 0); if (l -> lint != -1 && l -> pb != -1) { l -> len = OPLEN(instab[l -> insn].ops[0]) + l -> lint + 1; } } void insn_emit_indexed_aux(asmstate_t *as, line_t *l) { lw_expr_t e; if (l -> lint == 1) { int i; e = lwasm_fetch_expr(l, 0); i = lw_expr_intval(e); if (i < -128 || i > 127) { lwasm_register_error(as, l, E_BYTE_OVERFLOW); } } lwasm_emitop(l, instab[l -> insn].ops[0]); lwasm_emitop(l, l -> pb); l -> cycle_adj = lwasm_cycle_calc_ind(l); if (l -> lint > 0) { e = lwasm_fetch_expr(l, 0); lwasm_emitexpr(l, e, l -> lint); } } EMITFUNC(insn_emit_indexed) { insn_emit_indexed_aux(as, l); }