michael@0: /*  GRAPHITE2 LICENSING
michael@0: 
michael@0:     Copyright 2010, SIL International
michael@0:     All rights reserved.
michael@0: 
michael@0:     This library is free software; you can redistribute it and/or modify
michael@0:     it under the terms of the GNU Lesser General Public License as published
michael@0:     by the Free Software Foundation; either version 2.1 of License, or
michael@0:     (at your option) any later version.
michael@0: 
michael@0:     This program is distributed in the hope that it will be useful,
michael@0:     but WITHOUT ANY WARRANTY; without even the implied warranty of
michael@0:     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
michael@0:     Lesser General Public License for more details.
michael@0: 
michael@0:     You should also have received a copy of the GNU Lesser General Public
michael@0:     License along with this library in the file named "LICENSE".
michael@0:     If not, write to the Free Software Foundation, 51 Franklin Street, 
michael@0:     Suite 500, Boston, MA 02110-1335, USA or visit their web page on the 
michael@0:     internet at http://www.fsf.org/licenses/lgpl.html.
michael@0: 
michael@0: Alternatively, the contents of this file may be used under the terms of the
michael@0: Mozilla Public License (http://mozilla.org/MPL) or the GNU General Public
michael@0: License, as published by the Free Software Foundation, either version 2
michael@0: of the License or (at your option) any later version.
michael@0: */
michael@0: // This general interpreter interface.
michael@0: // Author: Tim Eves
michael@0: 
michael@0: // Build one of direct_machine.cpp or call_machine.cpp to implement this 
michael@0: // interface.
michael@0: 
michael@0: #pragma once
michael@0: #include <cstring>
michael@0: #include <graphite2/Types.h>
michael@0: #include "inc/Main.h"
michael@0: 
michael@0: #if defined(__GNUC__)
michael@0: #if defined(__clang__) || (__GNUC__ * 100 + __GNUC_MINOR__ * 10) < 430
michael@0: #define     HOT
michael@0: #if defined(__x86_64)
michael@0: #define     REGPARM(n)      __attribute__((regparm(n)))
michael@0: #else
michael@0: #define     REGPARM(n)
michael@0: #endif
michael@0: #else
michael@0: #define     HOT             __attribute__((hot))
michael@0: #if defined(__x86_64)
michael@0: #define     REGPARM(n)      __attribute__((hot, regparm(n)))
michael@0: #else
michael@0: #define     REGPARM(n)
michael@0: #endif
michael@0: #endif
michael@0: #else
michael@0: #define     HOT
michael@0: #define     REGPARM(n)
michael@0: #endif
michael@0: 
michael@0: namespace graphite2 {
michael@0: 
michael@0: // Forward declarations
michael@0: class Segment;
michael@0: class Slot;
michael@0: class SlotMap;
michael@0: 
michael@0: 
michael@0: namespace vm 
michael@0: {
michael@0: 
michael@0: 
michael@0: typedef void * instr;
michael@0: typedef Slot * slotref;
michael@0: 
michael@0: enum {VARARGS = 0xff, MAX_NAME_LEN=32};
michael@0: 
michael@0: enum opcode {
michael@0:     NOP = 0,
michael@0: 
michael@0:     PUSH_BYTE,      PUSH_BYTEU,     PUSH_SHORT,     PUSH_SHORTU,    PUSH_LONG,
michael@0: 
michael@0:     ADD,            SUB,            MUL,            DIV,
michael@0:     MIN_,           MAX_,
michael@0:     NEG,
michael@0:     TRUNC8,         TRUNC16,
michael@0: 
michael@0:     COND,
michael@0: 
michael@0:     AND,            OR,             NOT,
michael@0:     EQUAL,          NOT_EQ,
michael@0:     LESS,           GTR,            LESS_EQ,        GTR_EQ,
michael@0: 
michael@0:     NEXT,           NEXT_N,         COPY_NEXT,
michael@0:     PUT_GLYPH_8BIT_OBS,              PUT_SUBS_8BIT_OBS,   PUT_COPY,
michael@0:     INSERT,         DELETE,
michael@0:     ASSOC,
michael@0:     CNTXT_ITEM,
michael@0: 
michael@0:     ATTR_SET,       ATTR_ADD,       ATTR_SUB,
michael@0:     ATTR_SET_SLOT,
michael@0:     IATTR_SET_SLOT,
michael@0:     PUSH_SLOT_ATTR,                 PUSH_GLYPH_ATTR_OBS,
michael@0:     PUSH_GLYPH_METRIC,              PUSH_FEAT,
michael@0:     PUSH_ATT_TO_GATTR_OBS,          PUSH_ATT_TO_GLYPH_METRIC,
michael@0:     PUSH_ISLOT_ATTR,
michael@0: 
michael@0:     PUSH_IGLYPH_ATTR,    // not implemented
michael@0: 
michael@0:     POP_RET,                        RET_ZERO,           RET_TRUE,
michael@0:     IATTR_SET,                      IATTR_ADD,          IATTR_SUB,
michael@0:     PUSH_PROC_STATE,                PUSH_VERSION,
michael@0:     PUT_SUBS,                       PUT_SUBS2,          PUT_SUBS3,
michael@0:     PUT_GLYPH,                      PUSH_GLYPH_ATTR,    PUSH_ATT_TO_GLYPH_ATTR,
michael@0:     MAX_OPCODE,
michael@0:     // private opcodes for internal use only, comes after all other on disk opcodes
michael@0:     TEMP_COPY = MAX_OPCODE
michael@0: };
michael@0: 
michael@0: struct opcode_t 
michael@0: {
michael@0:     instr           impl[2];
michael@0:     uint8           param_sz;
michael@0:     char            name[MAX_NAME_LEN];
michael@0: };
michael@0: 
michael@0: 
michael@0: class Machine
michael@0: {
michael@0: public:
michael@0:     typedef int32  stack_t;
michael@0:     static size_t const STACK_ORDER  = 10,
michael@0:                         STACK_MAX    = 1 << STACK_ORDER,
michael@0:                         STACK_GUARD  = 2;
michael@0: 
michael@0:     class Code;
michael@0: 
michael@0:     enum status_t {
michael@0:         finished = 0,
michael@0:         stack_underflow,
michael@0:         stack_not_empty,
michael@0:         stack_overflow,
michael@0:         slot_offset_out_bounds
michael@0:     };
michael@0: 
michael@0:     Machine(SlotMap &) throw();
michael@0:     static const opcode_t *   getOpcodeTable() throw();
michael@0: 
michael@0:     CLASS_NEW_DELETE;
michael@0: 
michael@0:     SlotMap   & slotMap() const throw();
michael@0:     status_t    status() const throw();
michael@0:     operator bool () const throw();
michael@0: 
michael@0: private:
michael@0:     void    check_final_stack(const stack_t * const sp);
michael@0:     stack_t run(const instr * program, const byte * data,
michael@0:                 slotref * & map) HOT;
michael@0: 
michael@0:     SlotMap       & _map;
michael@0:     stack_t         _stack[STACK_MAX + 2*STACK_GUARD];
michael@0:     status_t        _status;
michael@0: };
michael@0: 
michael@0: inline Machine::Machine(SlotMap & map) throw()
michael@0: : _map(map), _status(finished)
michael@0: {
michael@0:     // Initialise stack guard +1 entries as the stack pointer points to the
michael@0:     //  current top of stack, hence the first push will never write entry 0.
michael@0:     // Initialising the guard space like this is unnecessary and is only
michael@0:     //  done to keep valgrind happy during fuzz testing.  Hopefully loop
michael@0:     //  unrolling will flatten this.
michael@0:     for (size_t n = STACK_GUARD + 1; n; --n)  _stack[n-1] = 0;
michael@0: }
michael@0: 
michael@0: inline SlotMap& Machine::slotMap() const throw()
michael@0: {
michael@0:     return _map;
michael@0: }
michael@0: 
michael@0: inline Machine::status_t Machine::status() const throw()
michael@0: {
michael@0:     return _status;
michael@0: }
michael@0: 
michael@0: inline void Machine::check_final_stack(const int32 * const sp)
michael@0: {
michael@0:     stack_t const * const base  = _stack + STACK_GUARD,
michael@0:                   * const limit = base + STACK_MAX;
michael@0:     if      (sp <  base)    _status = stack_underflow;       // This should be impossible now.
michael@0:     else if (sp >= limit)   _status = stack_overflow;        // So should this.
michael@0:     else if (sp != base)    _status = stack_not_empty;
michael@0: }
michael@0: 
michael@0: } // namespace vm
michael@0: } // namespace graphite2
michael@0: 
michael@0: 
michael@0: