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engine/thirdparty/graphite/src/call_machine.cpp

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+// SPDX-License-Identifier: MIT OR MPL-2.0 OR LGPL-2.1-or-later OR GPL-2.0-or-later
+// Copyright 2010, SIL International, All rights reserved.
+
+// This call threaded interpreter implmentation for machine.h
+// Author: Tim Eves
+
+// Build either this interpreter or the direct_machine implementation.
+// The call threaded interpreter is portable across compilers and
+// architectures as well as being useful to debug (you can set breakpoints on
+// opcodes) but is slower that the direct threaded interpreter by a factor of 2
+
+#include <cassert>
+#include <cstring>
+#include <graphite2/Segment.h>
+#include "inc/Machine.h"
+#include "inc/Segment.h"
+#include "inc/Slot.h"
+#include "inc/Rule.h"
+
+// Disable the unused parameter warning as th compiler is mistaken since dp
+// is always updated (even if by 0) on every opcode.
+#ifdef __GNUC__
+#pragma GCC diagnostic ignored "-Wunused-parameter"
+#endif
+
+#define registers           const byte * & dp, vm::Machine::stack_t * & sp, \
+                            vm::Machine::stack_t * const sb, regbank & reg
+
+// These are required by opcodes.h and should not be changed
+#define STARTOP(name)       bool name(registers) REGPARM(4);\
+                            bool name(registers) {
+#define ENDOP                   return (sp - sb)/Machine::STACK_MAX==0; \
+                            }
+
+#define EXIT(status)        { push(status); return false; }
+
+// This is required by opcode_table.h
+#define do_(name)           instr(name)
+
+
+using namespace graphite2;
+using namespace vm;
+
+struct regbank  {
+    slotref         is;
+    slotref *       map;
+    SlotMap       & smap;
+    slotref * const map_base;
+    const instr * & ip;
+    uint8           direction;
+    int8            flags;
+    Machine::status_t & status;
+};
+
+typedef bool        (* ip_t)(registers);
+
+// Pull in the opcode definitions
+// We pull these into a private namespace so these otherwise common names dont
+// pollute the toplevel namespace.
+namespace {
+#define smap    reg.smap
+#define seg     smap.segment
+#define is      reg.is
+#define ip      reg.ip
+#define map     reg.map
+#define mapb    reg.map_base
+#define flags   reg.flags
+#define dir     reg.direction
+#define status  reg.status
+
+#include "inc/opcodes.h"
+
+#undef smap
+#undef seg
+#undef is
+#undef ip
+#undef map
+#undef mapb
+#undef flags
+#undef dir
+}
+
+Machine::stack_t  Machine::run(const instr   * program,
+                               const byte    * data,
+                               slotref     * & map)
+
+{
+    assert(program != 0);
+
+    // Declare virtual machine registers
+    const instr   * ip = program-1;
+    const byte    * dp = data;
+    stack_t       * sp = _stack + Machine::STACK_GUARD,
+            * const sb = sp;
+    regbank         reg = {*map, map, _map, _map.begin()+_map.context(), ip, _map.dir(), 0, _status};
+
+    // Run the program
+    while ((reinterpret_cast<ip_t>(*++ip))(dp, sp, sb, reg)) {}
+    const stack_t ret = sp == _stack+STACK_GUARD+1 ? *sp-- : 0;
+
+    check_final_stack(sp);
+    map = reg.map;
+    *map = reg.is;
+    return ret;
+}
+
+// Pull in the opcode table
+namespace {
+#include "inc/opcode_table.h"
+}
+
+const opcode_t * Machine::getOpcodeTable() throw()
+{
+    return opcode_table;
+}