}/* z_get_child */
/*
* z_get_next_prop, store the number of the first or next property.
*
* Process.zargs[0] = object
* Process.zargs[1] = address of current property (0 gets the first property)
*
*/
internal static void ZGetNextProp()
{
zbyte value;
if (Process.zargs[0] == 0)
{
Err.RuntimeError(ErrorCodes.ERR_GET_NEXT_PROP_0);
Process.Store(0);
return;
}
/* Property id is in bottom five (six) bits */
zbyte mask = (zbyte)((Main.h_version <= ZMachine.V3) ? 0x1f : 0x3f);
/* Load address of first property */
zword prop_addr = FirstProperty(Process.zargs[0]);
if (Process.zargs[1] != 0)
{
/* Scan down the property list */
do
{
FastMem.LowByte(prop_addr, out value);
prop_addr = NextProperty(prop_addr);
} while ((value & mask) > Process.zargs[1]);
/* Exit if the property does not exist */
if ((value & mask) != Process.zargs[1])
{
Err.RuntimeError(ErrorCodes.ERR_NO_PROP);
}
}
/* Return the property id */
FastMem.LowByte(prop_addr, out value);
Process.Store((zword)(value & mask));
}/* z_get_next_prop */
}/* call */
/*
* ret
*
* Return from the current subroutine and restore the previous stack
* frame. The result may be stored (0), thrown away (1) or pushed on
* the stack (2). In the latter case a direct call has been finished
* and we must exit the interpreter loop.
*
*/
internal static void ret(zword value)
{
long pc;
int ct;
if (main.sp > main.fp)
{
Err.runtime_error(ErrorCodes.ERR_STK_UNDF);
}
main.sp = main.fp;
DebugState.Output("Removing Frame: {0}", main.frame_count);
ct = main.stack[main.sp++] >> (main.option_save_quetzal == true ? 12 : 8);
main.frame_count--;
main.fp = 1 + main.stack[main.sp++]; // fp = stack + 1 + *sp++;
pc = main.stack[main.sp++];
pc = (main.stack[main.sp++] << 9) | (int)pc; // TODO Really don't trust casting PC to int
FastMem.SET_PC(pc);
/* Handle resulting value */
if (ct == 0)
{
store(value);
}
if (ct == 2)
{
main.stack[--main.sp] = value;
}
/* Stop main loop for direct calls */
if (ct == 2)
{
finished++;
}
}/* ret */
}/* z_get_prop_len */
/*
* z_get_sibling, store the sibling of an object.
*
* Process.zargs[0] = object
*
*/
internal static void ZGetSibling()
{
zword obj_addr;
if (Process.zargs[0] == 0)
{
Err.RuntimeError(ErrorCodes.ERR_GET_SIBLING_0);
Process.Store(0);
Process.Branch(false);
return;
}
obj_addr = ObjectAddress(Process.zargs[0]);
if (Main.h_version <= ZMachine.V3)
{
/* Get sibling id from object */
obj_addr += O1_SIBLING;
FastMem.LowByte(obj_addr, out byte sibling);
/* Store sibling and branch */
Process.Store(sibling);
Process.Branch(sibling > 0); // TODO I'm not sure about this logic Process.branch (sibling);
// I think it means if the sibling isn't zero, jump..
}
else
{
/* Get sibling id from object */
obj_addr += O4_SIBLING;
FastMem.LowWord(obj_addr, out ushort sibling);
/* Store sibling and branch */
Process.Store(sibling);
Process.Branch(sibling > 0);
}
}/* z_get_sibling */
}/* z_set_attr */
/*
* z_test_attr, branch if an object attribute is set.
*
* Process.zargs[0] = object
* Process.zargs[1] = number of attribute to test
*
*/
internal static void ZTestAttr()
{
zword obj_addr;
if (Process.zargs[1] > ((Main.h_version <= ZMachine.V3) ? 31 : 47))
{
Err.RuntimeError(ErrorCodes.ERR_ILL_ATTR);
}
/* If we are monitoring attribute testing display a short note */
if (Main.option_attribute_testing == true)
{
Stream.StreamMssgOn();
Text.PrintString("@test_attr ");
Text.PrintObject(Process.zargs[0]);
Text.PrintString(" ");
Text.PrintNum(Process.zargs[1]);
Stream.StreamMssgOff();
}
if (Process.zargs[0] == 0)
{
Err.RuntimeError(ErrorCodes.ERR_TEST_ATTR_0);
Process.Branch(false);
return;
}
/* Get attribute address */
obj_addr = (zword)(ObjectAddress(Process.zargs[0]) + Process.zargs[1] / 8);
/* Load attribute byte */
FastMem.LowByte(obj_addr, out byte value);
/* Test attribute */
Process.Branch((value & (0x80 >> (Process.zargs[1] & 7))) > 0);
}/* z_test_attr */
/*
* object_address
*
* Calculate the address of an object.
*
*/
internal static zword object_address(zword obj)
{
/* Check object number */
if (obj > ((main.h_version <= ZMachine.V3) ? 255 : MAX_OBJECT))
{
Text.print_string("@Attempt to address illegal object ");
Text.print_num(obj);
Text.print_string(". This is normally fatal.");
Buffer.new_line();
Err.runtime_error(ErrorCodes.ERR_ILL_OBJ);
}
/* Return object address */
if (main.h_version <= ZMachine.V3)
{
return((zword)(main.h_objects + ((obj - 1) * O1_SIZE + 62)));
}
else
{
return((zword)(main.h_objects + ((obj - 1) * O4_SIZE + 126)));
}
}/* object_address */
/*
* Save a game using Quetzal format. Return 1 if OK, 0 if failed.
*/
internal static zword SaveQuetzal(FileStream svf, System.IO.Stream stf)
{
zlong stkslen = 0;
zword i, j, n;
int nvars, nargs, nstk, p;
zbyte var;
long cmempos, stkspos;
int c;
/* Write `IFZS' header. */
if (!WriteChunk(svf, ID_FORM, 0))
{
return(0);
}
if (!WriteLong(svf, ID_IFZS))
{
return(0);
}
/* Write `IFhd' chunk. */
FastMem.GetPc(out long pc);
if (!WriteChunk(svf, ID_IFhd, 13))
{
return(0);
}
if (!WriteWord(svf, Main.h_release))
{
return(0);
}
for (i = ZMachine.H_SERIAL; i < ZMachine.H_SERIAL + 6; ++i)
{
if (!WriteByte(svf, FastMem.ZMData[FastMem.Zmp + i]))
{
return(0);
}
}
if (!WriteWord(svf, Main.h_checksum))
{
return(0);
}
if (!WriteLong(svf, pc << 8)) /* Includes pad. */ return {
(0);
}
/* Write `CMem' chunk. */
if ((cmempos = svf.Position) < 0)
{
return(0);
}
if (!WriteChunk(svf, ID_CMem, 0))
{
return(0);
}
// (void) fseek (stf, 0, SEEK_SET);
stf.Position = 0;
uint cmemlen;
/* j holds current run length. */
for (i = 0, j = 0, cmemlen = 0; i < Main.h_dynamic_size; ++i)
{
if ((c = stf.ReadByte()) == -1)
{
return(0);
}
c ^= FastMem.ZMData[i];
if (c == 0)
{
++j; /* It's a run of equal bytes. */
}
else
{
/* Write out any run there may be. */
if (j > 0)
{
for (; j > 0x100; j -= 0x100)
{
if (!WriteRun(svf, 0xFF))
{
return(0);
}
cmemlen += 2;
}
if (!WriteRun(svf, (byte)(j - 1)))
{
return(0);
}
cmemlen += 2;
j = 0;
}
/* Any runs are now written. Write this (nonzero) byte. */
if (!WriteByte(svf, (zbyte)c))
{
return(0);
}
++cmemlen;
}
}
/*
* Reached end of dynamic memory. We ignore any unwritten run there may be
* at this point.
*/
if ((cmemlen & 1) > 0) /* Chunk length must be even. */
{
if (!WriteByte(svf, 0))
{
return(0);
}
}
/* Write `Stks' chunk. You are not expected to understand this. ;) */
if ((stkspos = svf.Position) < 0)
{
return(0);
}
if (!WriteChunk(svf, ID_Stks, 0))
{
return(0);
}
using var buffer = SpanOwner <zword> .Allocate(General.STACK_SIZE / 4 + 1);
var frames = buffer.Span;
/*
* We construct a list of frame indices, most recent first, in `frames'.
* These indices are the offsets into the `stack' array of the word before
* the first word pushed in each frame.
*/
frames[0] = (zword)Main.sp; /* The frame we'd get by doing a call now. */
for (i = (zword)(Main.fp + 4), n = 0; i < General.STACK_SIZE + 4; i = (zword)(Main.Stack[i - 3] + 5))
{
frames[++n] = i;
}
/*
* All versions other than V6 can use evaluation stack outside a function
* context. We write a faked stack frame (most fields zero) to cater for
* this.
*/
if (Main.h_version != ZMachine.V6)
{
for (i = 0; i < 6; ++i)
{
if (!WriteByte(svf, 0))
{
return(0);
}
}
nstk = General.STACK_SIZE - frames[n];
if (!WriteWord(svf, nstk))
{
return(0);
}
for (j = General.STACK_SIZE - 1; j >= frames[n]; --j)
{
if (!WriteWord(svf, Main.Stack[j]))
{
return(0);
}
}
stkslen = (zword)(8 + 2 * nstk);
}
/* Write out the rest of the stack frames. */
for (i = n; i > 0; --i)
{
p = frames[i] - 4; // p = stack + frames[i] - 4; /* Points to call frame. */
nvars = (Main.Stack[p] & 0x0F00) >> 8;
nargs = Main.Stack[p] & 0x00FF;
nstk = (zword)(frames[i] - frames[i - 1] - nvars - 4);
pc = ((zlong)Main.Stack[p + 3] << 9) | Main.Stack[p + 2];
switch (Main.Stack[p] & 0xF000) /* Check type of call. */
{
case 0x0000: /* Function. */
var = FastMem.ZMData[FastMem.Zmp + pc];
pc = ((pc + 1) << 8) | (zlong)nvars;
break;
case 0x1000: /* Procedure. */
var = 0;
pc = (pc << 8) | 0x10 | (zlong)nvars; /* Set procedure flag. */
break;
/* case 0x2000: */
default:
Err.RuntimeError(ErrorCodes.ERR_SAVE_IN_INTER);
return(0);
}
if (nargs != 0)
{
nargs = (zword)((1 << nargs) - 1); /* Make args into bitmap. */
}
/* Write the main part of the frame... */
if (!WriteLong(svf, pc) ||
!WriteByte(svf, var) ||
!WriteByte(svf, (byte)nargs) ||
!WriteWord(svf, nstk))
{
return(0);
}
/* Write the variables and eval stack. */
for (j = 0, --p; j < nvars + nstk; ++j, --p)
{
if (!WriteWord(svf, Main.Stack[p]))
{
return(0);
}
}
/* Calculate length written thus far. */
stkslen += (zword)(8 + 2 * (nvars + nstk));
}
/* Fill in variable chunk lengths. */
uint ifzslen = 3 * 8 + 4 + 14 + cmemlen + stkslen;
if ((cmemlen & 1) > 0)
{
++ifzslen;
}
svf.Position = 4;
if (!WriteLong(svf, ifzslen))
{
return(0);
}
svf.Position = cmempos + 4;
if (!WriteLong(svf, cmemlen))
{
return(0);
}
svf.Position = stkspos + 4;
if (!WriteLong(svf, stkslen))
{
return(0);
}
/* After all that, still nothing went wrong! */
return(1);
}
}/* __extended__ */
/*
* __illegal__
*
* Exit game because an unknown opcode has been hit.
*
*/
static void __illegal__()
{
Err.runtime_error(ErrorCodes.ERR_ILL_OPCODE);
}/* __illegal__ */
}/* interpret */
/*
* call
*
* Call a subroutine. Save PC and FP then load new PC and initialise
* new stack frame. Note that the caller may legally provide less or
* more arguments than the function actually has. The call type "ct"
* can be 0 (z_call_s), 1 (z_call_n) or 2 (direct call).
*
*/
internal static void call(zword routine, int argc, int args_offset, int ct)
{
long pc;
zword value;
zbyte count;
int i;
if (main.sp < 4)//if (sp - stack < 4)
{
Err.runtime_error(ErrorCodes.ERR_STK_OVF);
}
FastMem.GET_PC(out pc);
main.stack[--main.sp] = (zword)(pc >> 9);
main.stack[--main.sp] = (zword)(pc & 0x1ff);
main.stack[--main.sp] = (zword)(main.fp - 1); // *--sp = (zword) (fp - stack - 1);
main.stack[--main.sp] = (zword)(argc | (ct << (main.option_save_quetzal == true ? 12 : 8)));
main.fp = main.sp;
main.frame_count++;
DebugState.Output("Added Frame: {0} -> {1}:{2}:{3}:{4}",
main.frame_count,
main.stack[main.sp + 0],
main.stack[main.sp + 1],
main.stack[main.sp + 2],
main.stack[main.sp + 3]);
/* Calculate byte address of routine */
if (main.h_version <= ZMachine.V3)
{
pc = (long)routine << 1;
}
else if (main.h_version <= ZMachine.V5)
{
pc = (long)routine << 2;
}
else if (main.h_version <= ZMachine.V7)
{
pc = ((long)routine << 2) + ((long)main.h_functions_offset << 3);
}
else /* (h_version <= V8) */
{
pc = (long)routine << 3;
}
if (pc >= main.story_size)
{
Err.runtime_error(ErrorCodes.ERR_ILL_CALL_ADDR);
}
FastMem.SET_PC(pc);
/* Initialise local variables */
FastMem.CODE_BYTE(out count);
if (count > 15)
{
Err.runtime_error(ErrorCodes.ERR_CALL_NON_RTN);
}
if (main.sp < count)
{
Err.runtime_error(ErrorCodes.ERR_STK_OVF);
}
if (main.option_save_quetzal == true)
{
main.stack[main.fp] |= (zword)(count << 8); /* Save local var count for Quetzal. */
}
value = 0;
for (i = 0; i < count; i++)
{
if (main.h_version <= ZMachine.V4) /* V1 to V4 games provide default */
{
FastMem.CODE_WORD(out value); /* values for all local variables */
}
main.stack[--main.sp] = (zword)((argc-- > 0) ? zargs[args_offset + i] : value);
//*--sp = (zword) ((argc-- > 0) ? args[i] : value);
}
/* Start main loop for direct calls */
if (ct == 2)
{
interpret();
}
}/* call */
}/* z_get_sibling */
/*
* z_insert_obj, make an object the first child of another object.
*
* Process.zargs[0] = object to be moved
* Process.zargs[1] = destination object
*
*/
internal static void z_insert_obj()
{
zword obj1 = Process.zargs[0];
zword obj2 = Process.zargs[1];
zword obj1_addr;
zword obj2_addr;
/* If we are monitoring object movements display a short note */
if (main.option_object_movement == true)
{
Stream.stream_mssg_on();
Text.print_string("@move_obj ");
Text.print_object(obj1);
Text.print_string(" ");
Text.print_object(obj2);
Stream.stream_mssg_off();
}
if (obj1 == 0)
{
Err.runtime_error(ErrorCodes.ERR_MOVE_OBJECT_0);
return;
}
if (obj2 == 0)
{
Err.runtime_error(ErrorCodes.ERR_MOVE_OBJECT_TO_0);
return;
}
/* Get addresses of both objects */
obj1_addr = object_address(obj1);
obj2_addr = object_address(obj2);
/* Remove object 1 from current parent */
unlink_object(obj1);
/* Make object 1 first child of object 2 */
if (main.h_version <= ZMachine.V3)
{
zbyte child;
obj1_addr += O1_PARENT;
FastMem.SET_BYTE(obj1_addr, (zbyte)obj2);
obj2_addr += O1_CHILD;
FastMem.LOW_BYTE(obj2_addr, out child);
FastMem.SET_BYTE(obj2_addr, (zbyte)obj1);
obj1_addr += (zword)(O1_SIBLING - O1_PARENT);
FastMem.SET_BYTE(obj1_addr, child);
}
else
{
zword child;
obj1_addr += O4_PARENT;
FastMem.SET_WORD(obj1_addr, obj2);
obj2_addr += O4_CHILD;
FastMem.LOW_WORD(obj2_addr, out child);
FastMem.SET_WORD(obj2_addr, obj1);
obj1_addr += (zword)(O4_SIBLING - O4_PARENT);
FastMem.SET_WORD(obj1_addr, child);
}
}/* z_insert_obj */
}/* z_get_parent */
/*
* z_get_prop, store the value of an object property.
*
* Process.zargs[0] = object
* Process.zargs[1] = number of property to be examined
*
*/
internal static void z_get_prop()
{
zword prop_addr;
zword wprop_val;
zbyte bprop_val;
zbyte value;
zbyte mask;
if (Process.zargs[0] == 0)
{
Err.runtime_error(ErrorCodes.ERR_GET_PROP_0);
Process.store(0);
return;
}
/* Property id is in bottom five (six) bits */
mask = (zbyte)((main.h_version <= ZMachine.V3) ? 0x1f : 0x3f);
/* Load address of first property */
prop_addr = first_property(Process.zargs[0]);
/* Scan down the property list */
for (; ;)
{
FastMem.LOW_BYTE(prop_addr, out value);
if ((value & mask) <= Process.zargs[1])
{
break;
}
prop_addr = next_property(prop_addr);
}
if ((value & mask) == Process.zargs[1]) /* property found */
/* Load property (byte or word sized) */
{
prop_addr++;
if ((main.h_version <= ZMachine.V3 && !((value & 0xe0) > 0)) || (main.h_version >= ZMachine.V4 && !((value & 0xc0) > 0)))
{
FastMem.LOW_BYTE(prop_addr, out bprop_val);
wprop_val = bprop_val;
}
else
{
FastMem.LOW_WORD(prop_addr, out wprop_val);
}
}
else /* property not found */
/* Load default value */
{
prop_addr = (zword)(main.h_objects + 2 * (Process.zargs[1] - 1));
FastMem.LOW_WORD(prop_addr, out wprop_val);
}
/* Store the property value */
Process.store(wprop_val);
}/* z_get_prop */
}/* next_property */
/*
* unlink_object
*
* Unlink an object from its parent and siblings.
*
*/
static void unlink_object(zword object_var)
{
zword obj_addr;
zword parent_addr;
zword sibling_addr;
if (object_var == 0)
{
Err.runtime_error(ErrorCodes.ERR_REMOVE_OBJECT_0);
return;
}
obj_addr = object_address(object_var);
if (main.h_version <= ZMachine.V3)
{
zbyte parent;
zbyte younger_sibling;
zbyte older_sibling;
zbyte zero = 0;
/* Get parent of object, and return if no parent */
obj_addr += O1_PARENT;
FastMem.LOW_BYTE(obj_addr, out parent);
if (parent == 0)
{
return;
}
/* Get (older) sibling of object and set both parent and sibling
* pointers to 0 */
FastMem.SET_BYTE(obj_addr, zero);
obj_addr += (zword)(O1_SIBLING - O1_PARENT);
FastMem.LOW_BYTE(obj_addr, out older_sibling);
FastMem.SET_BYTE(obj_addr, zero);
/* Get first child of parent (the youngest sibling of the object) */
parent_addr = (zword)(object_address(parent) + O1_CHILD);
FastMem.LOW_BYTE(parent_addr, out younger_sibling);
/* Remove object from the list of siblings */
if (younger_sibling == object_var)
{
FastMem.SET_BYTE(parent_addr, older_sibling);
}
else
{
do
{
sibling_addr = (zword)(object_address(younger_sibling) + O1_SIBLING);
FastMem.LOW_BYTE(sibling_addr, out younger_sibling);
} while (younger_sibling != object_var);
FastMem.SET_BYTE(sibling_addr, older_sibling);
}
}
else
{
zword parent;
zword younger_sibling;
zword older_sibling;
zword zero = 0;
/* Get parent of object, and return if no parent */
obj_addr += O4_PARENT;
FastMem.LOW_WORD(obj_addr, out parent);
if (parent == 0)
{
return;
}
/* Get (older) sibling of object and set both parent and sibling
* pointers to 0 */
FastMem.SET_WORD(obj_addr, zero);
obj_addr += (zword)(O4_SIBLING - O4_PARENT);
FastMem.LOW_WORD(obj_addr, out older_sibling);
FastMem.SET_WORD(obj_addr, zero);
/* Get first child of parent (the youngest sibling of the object) */
parent_addr = (zword)(object_address(parent) + O4_CHILD);
FastMem.LOW_WORD(parent_addr, out younger_sibling);
/* Remove object from the list of siblings */
if (younger_sibling == object_var)
{
FastMem.SET_WORD(parent_addr, older_sibling);
}
else
{
do
{
sibling_addr = (zword)(object_address(younger_sibling) + O4_SIBLING);
FastMem.LOW_WORD(sibling_addr, out younger_sibling);
} while (younger_sibling != object_var);
FastMem.SET_WORD(sibling_addr, older_sibling);
}
}
}/* unlink_object */
static void decode_text(string_type st, zword addr)
{
// zword* ptr;
long byte_addr;
zword c2;
zword code;
zbyte c, prev_c = 0;
int shift_state = 0;
int shift_lock = 0;
int status = 0;
// ptr = NULL; /* makes compilers shut up */
byte_addr = 0;
if (resolution == 0)
{
find_resolution();
}
/* Calculate the byte address if necessary */
if (st == string_type.ABBREVIATION)
{
byte_addr = (long)addr << 1;
}
else if (st == string_type.HIGH_STRING)
{
if (main.h_version <= ZMachine.V3)
{
byte_addr = (long)addr << 1;
}
else if (main.h_version <= ZMachine.V5)
{
byte_addr = (long)addr << 2;
}
else if (main.h_version <= ZMachine.V7)
{
byte_addr = ((long)addr << 2) + ((long)main.h_strings_offset << 3);
}
else /* (h_version <= V8) */
{
byte_addr = (long)addr << 3;
}
if (byte_addr >= main.story_size)
{
Err.runtime_error(ErrorCodes.ERR_ILL_PRINT_ADDR);
}
}
/* Loop until a 16bit word has the highest bit set */
if (st == string_type.VOCABULARY)
{
ptrDt = 0;
}
do
{
int i;
/* Fetch the next 16bit word */
if (st == string_type.LOW_STRING || st == string_type.VOCABULARY)
{
FastMem.LOW_WORD(addr, out code);
addr += 2;
}
else if (st == string_type.HIGH_STRING || st == string_type.ABBREVIATION)
{
FastMem.HIGH_WORD(byte_addr, out code);
byte_addr += 2;
}
else
{
FastMem.CODE_WORD(out code);
}
/* Read its three Z-characters */
for (i = 10; i >= 0; i -= 5)
{
zword abbr_addr;
zword ptr_addr;
zword zc;
c = (zbyte)((code >> i) & 0x1f);
switch (status)
{
case 0: /* normal operation */
if (shift_state == 2 && c == 6)
{
status = 2;
}
else if (main.h_version == ZMachine.V1 && c == 1)
{
Buffer.new_line();
}
else if (main.h_version >= ZMachine.V2 && shift_state == 2 && c == 7)
{
Buffer.new_line();
}
else if (c >= 6)
{
outchar(st, alphabet(shift_state, c - 6));
}
else if (c == 0)
{
outchar(st, ' ');
}
else if (main.h_version >= ZMachine.V2 && c == 1)
{
status = 1;
}
else if (main.h_version >= ZMachine.V3 && c <= 3)
{
status = 1;
}
else
{
shift_state = (shift_lock + (c & 1) + 1) % 3;
if (main.h_version <= ZMachine.V2 && c >= 4)
{
shift_lock = shift_state;
}
break;
}
shift_state = shift_lock;
break;
case 1: /* abbreviation */
ptr_addr = (zword)(main.h_abbreviations + 64 * (prev_c - 1) + 2 * c);
FastMem.LOW_WORD(ptr_addr, out abbr_addr);
decode_text(string_type.ABBREVIATION, abbr_addr);
status = 0;
break;
case 2: /* ZSCII character - first part */
status = 3;
break;
case 3: /* ZSCII character - second part */
zc = (zword)((prev_c << 5) | c);
c2 = translate_from_zscii((zbyte)zc); // TODO This doesn't seem right
outchar(st, c2);
status = 0;
break;
}
prev_c = c;
}
} while (!((code & 0x8000) > 0));
if (st == string_type.VOCABULARY)
{
ptrDt = 0;
}
}/* decode_text */
}/* next_property */
/*
* unlink_object
*
* Unlink an object from its parent and siblings.
*
*/
private static void UnlinkObject(zword object_var)
{
zword parent_addr;
zword sibling_addr;
if (object_var == 0)
{
Err.RuntimeError(ErrorCodes.ERR_REMOVE_OBJECT_0);
return;
}
zword obj_addr = ObjectAddress(object_var);
if (Main.h_version <= ZMachine.V3)
{
zbyte zero = 0;
/* Get parent of object, and return if no parent */
obj_addr += O1_PARENT;
FastMem.LowByte(obj_addr, out byte parent);
if (parent == 0)
{
return;
}
/* Get (older) sibling of object and set both parent and sibling
* pointers to 0 */
FastMem.SetByte(obj_addr, zero);
obj_addr += (zword)(O1_SIBLING - O1_PARENT);
FastMem.LowByte(obj_addr, out byte older_sibling);
FastMem.SetByte(obj_addr, zero);
/* Get first child of parent (the youngest sibling of the object) */
parent_addr = (zword)(ObjectAddress(parent) + O1_CHILD);
FastMem.LowByte(parent_addr, out byte younger_sibling);
/* Remove object from the list of siblings */
if (younger_sibling == object_var)
{
FastMem.SetByte(parent_addr, older_sibling);
}
else
{
do
{
sibling_addr = (zword)(ObjectAddress(younger_sibling) + O1_SIBLING);
FastMem.LowByte(sibling_addr, out younger_sibling);
} while (younger_sibling != object_var);
FastMem.SetByte(sibling_addr, older_sibling);
}
}
else
{
zword zero = 0;
/* Get parent of object, and return if no parent */
obj_addr += O4_PARENT;
FastMem.LowWord(obj_addr, out zword parent);
if (parent == 0)
{
return;
}
/* Get (older) sibling of object and set both parent and sibling
* pointers to 0 */
FastMem.SetWord(obj_addr, zero);
obj_addr += (zword)(O4_SIBLING - O4_PARENT);
FastMem.LowWord(obj_addr, out ushort older_sibling);
FastMem.SetWord(obj_addr, zero);
/* Get first child of parent (the youngest sibling of the object) */
parent_addr = (zword)(ObjectAddress(parent) + O4_CHILD);
FastMem.LowWord(parent_addr, out ushort younger_sibling);
/* Remove object from the list of siblings */
if (younger_sibling == object_var)
{
FastMem.SetWord(parent_addr, older_sibling);
}
else
{
do
{
sibling_addr = (zword)(ObjectAddress(younger_sibling) + O4_SIBLING);
FastMem.LowWord(sibling_addr, out younger_sibling);
} while (younger_sibling != object_var);
FastMem.SetWord(sibling_addr, older_sibling);
}
}
}/* unlink_object */
