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view lwasm/instab.h @ 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 | 4fd16faa4d93 |
children | e97f9a302c6a |
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/* instab.h Copyright © 2008 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/>. Contains definitions for the instruction table */ #ifndef __instab_h_seen__ #define __instab_h_seen__ #include "lwasm.h" typedef struct { char *opcode; /* the mneumonic */ int ops[4]; /* opcode values for up to four addr modes */ void (*parse)(asmstate_t *as, line_t *l, char **optr); /* parse operand for insn */ void (*resolve)(asmstate_t *as, line_t *l, int force); /* resolve instruction to code */ void (*emit)(asmstate_t *as, line_t *l); /* resolve instruction to code */ int flags; /* flag for this instruction */ } instab_t; enum { lwasm_insn_cond = 1, /* conditional instruction */ lwasm_insn_endm = 1 << 1, /* end of macro */ lwasm_insn_setsym = 1 << 2, /* insn sets symbol address */ lwasm_insn_is6309 = 1 << 3, /* insn is 6309 only */ lwasm_insn_struct = 1 << 4, /* insn allowed in a struct */ lwasm_insn_setdata = 1 << 5, /* insn uses the data address for symbols */ lwasm_insn_is6800 = 1 << 6, /* insn is a 6800 compatibility operation */ lwasm_insn_is6809 = 1 << 7, /* insn is 6809 only */ lwasm_insn_is6809conv = 1 << 8, /* insn is 6809 convenience only */ lwasm_insn_is6309conv = 1 << 9, /* insn is 6309 convenience only */ lwasm_insn_normal = 0 }; #define PARSEFUNC(fn) void (fn)(asmstate_t *as, line_t *l, char **p) #define RESOLVEFUNC(fn) void (fn)(asmstate_t *as, line_t *l, int force) #define EMITFUNC(fn) void (fn)(asmstate_t *as, line_t *l) extern instab_t instab[]; #endif //__instab_h_seen__