}/* z_check_arg_count */
/*
* z_jump, jump unconditionally to the given address.
*
* zargs[0] = PC relative address
*
*/
internal static void z_jump()
{
long pc;
FastMem.GET_PC(out pc);
pc += (short)zargs[0] - 2; // TODO This actually counts on an overflow to work
if (pc >= main.story_size)
{
Err.runtime_error(ErrorCodes.ERR_ILL_JUMP_ADDR);
}
FastMem.SET_PC(pc);
}/* z_jump */
}/* ret */
/*
* branch
*
* Take a jump after an instruction based on the flag, either true or
* false. The branch can be short or long; it is encoded in one or two
* bytes respectively. When bit 7 of the first byte is set, the jump
* takes place if the flag is true; otherwise it is taken if the flag
* is false. When bit 6 of the first byte is set, the branch is short;
* otherwise it is long. The offset occupies the bottom 6 bits of the
* first byte plus all the bits in the second byte for long branches.
* Uniquely, an offset of 0 means return false, and an offset of 1 is
* return true.
*
*/
internal static void branch(bool flag)
{
long pc;
zword offset;
zbyte specifier;
zbyte off1;
zbyte off2;
FastMem.CODE_BYTE(out specifier);
off1 = (zbyte)(specifier & 0x3f);
if (!flag)
{
specifier ^= 0x80;
}
if ((specifier & 0x40) == 0)
{ // if (!(specifier & 0x40)) { /* it's a long branch */
if ((off1 & 0x20) > 0) /* propagate sign bit */
{
off1 |= 0xc0;
}
FastMem.CODE_BYTE(out off2);
offset = (zword)((off1 << 8) | off2);
}
else
{
offset = off1; /* it's a short branch */
}
if ((specifier & 0x80) > 0)
{
if (offset > 1)
{ /* normal branch */
FastMem.GET_PC(out pc);
pc += (short)offset - 2;
FastMem.SET_PC(pc);
}
else
{
ret(offset); /* special case, return 0 or 1 */
}
}
}/* branch */
}/* storew */
/*
* z_restart, re-load dynamic area, clear the stack and set the PC.
*
* no zargs used
*
*/
internal static void z_restart()
{
Buffer.flush_buffer();
os_.restart_game(ZMachine.RESTART_BEGIN);
Random.seed_random(0);
if (!first_restart)
{
story_fp.Position = init_fp_pos;
int read = story_fp.Read(ZMData, 0, main.h_dynamic_size);
if (read != main.h_dynamic_size)
{
os_.fatal("Story file read error");
}
}
else
{
first_restart = false;
}
restart_header();
Screen.restart_screen();
main.sp = main.fp = General.STACK_SIZE; // TODO Critical to make sure this logic works; sp = fp = stack + STACK_SIZE;
main.frame_count = 0;
if (main.h_version != ZMachine.V6)
{
zword pc = main.h_start_pc;
FastMem.SET_PC((int)pc);
}
else
{
Process.call(main.h_start_pc, 0, 0, 0);
}
os_.restart_game(ZMachine.RESTART_END);
}/* z_restart */
}/* 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 */
}/* 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 */
/*
* Restore a saved game using Quetzal format. Return 2 if OK, 0 if an error
* occurred before any damage was done, -1 on a fatal error.
*/
internal static zword restore_quetzal(FileStream svf, System.IO.Stream stf)
{
zlong ifzslen, currlen, tmpl;
zlong pc;
zword i, tmpw;
zword fatal = 0; /* Set to -1 when errors must be fatal. */
zbyte skip, progress = GOT_NONE;
int x, y;
/* Check it's really an `IFZS' file. */
if (!read_long(svf, out tmpl) ||
!read_long(svf, out ifzslen) ||
!read_long(svf, out currlen))
{
return(0);
}
if (tmpl != ID_FORM || currlen != ID_IFZS)
{
Text.print_string("This is not a saved game file!\n");
return(0);
}
if (((ifzslen & 1) > 0) || ifzslen < 4) /* Sanity checks. */ return {
(0);
}
ifzslen -= 4;
/* Read each chunk and process it. */
while (ifzslen > 0)
{
/* Read chunk header. */
if (ifzslen < 8) /* Couldn't contain a chunk. */ return {
(0);
}
if (!read_long(svf, out tmpl) ||
!read_long(svf, out currlen))
{
return(0);
}
ifzslen -= 8; /* Reduce remaining by size of header. */
/* Handle chunk body. */
if (ifzslen < currlen) /* Chunk goes past EOF?! */ return {
(0);
}
skip = (byte)(currlen & 1);
ifzslen -= currlen + (zlong)skip;
switch (tmpl)
{
/* `IFhd' header chunk; must be first in file. */
case 1229351012: // IFhd
if ((progress & GOT_HEADER) > 0)
{
Text.print_string("Save file has two IFZS chunks!\n");
return(fatal);
}
progress |= GOT_HEADER;
if (currlen < 13 ||
!read_word(svf, out tmpw))
{
return(fatal);
}
if (tmpw != main.h_release)
{
progress = GOT_ERROR;
}
for (i = ZMachine.H_SERIAL; i < ZMachine.H_SERIAL + 6; ++i)
{
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
if (x != FastMem.ZMData[FastMem.zmp + i])
{
progress = GOT_ERROR;
}
}
if (!read_word(svf, out tmpw))
{
return(fatal);
}
if (tmpw != main.h_checksum)
{
progress = GOT_ERROR;
}
if ((progress & GOT_ERROR) > 0)
{
Text.print_string("File was not saved from this story!\n");
return(fatal);
}
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
pc = (zlong)x << 16;
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
pc |= (zlong)x << 8;
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
pc |= (zlong)x;
fatal = zword.MaxValue; /* Setting PC means errors must be fatal. */ // TODO make sure this works
FastMem.SET_PC(pc);
for (i = 13; i < currlen; ++i)
{
svf.ReadByte(); /* Skip rest of chunk. */
}
break;
/* `Stks' stacks chunk; restoring this is quite complex. ;) */
case 1400138611: // ID_Stks:
if ((progress & GOT_STACK) > 0)
{
Text.print_string("File contains two stack chunks!\n");
break;
}
progress |= GOT_STACK;
fatal = zword.MaxValue;; /* Setting SP means errors must be fatal. */
// sp = stack + General.STACK_SIZE;
main.sp = main.stack.Length;
/*
* All versions other than V6 may use evaluation stack outside
* any function context. As a result a faked function context
* will be present in the file here. We skip this context, but
* load the associated stack onto the stack proper...
*/
if (main.h_version != ZMachine.V6)
{
if (currlen < 8)
{
return(fatal);
}
for (i = 0; i < 6; ++i)
{
if (svf.ReadByte() != 0)
{
return(fatal);
}
}
if (!read_word(svf, out tmpw))
{
return(fatal);
}
if (tmpw > General.STACK_SIZE)
{
Text.print_string("Save-file has too much stack (and I can't cope).\n");
return(fatal);
}
currlen -= 8;
if (currlen < tmpw * 2)
{
return(fatal);
}
for (i = 0; i < tmpw; ++i)
{
// if (!read_word(svf, --sp)) return fatal;
if (!read_word(svf, out main.stack[--main.sp]))
{
return(fatal);
}
}
currlen -= (zword)(tmpw * 2);
}
/* We now proceed to load the main block of stack frames. */
for (main.fp = main.stack.Length, main.frame_count = 0;
currlen > 0;
currlen -= 8, ++main.frame_count)
{
if (currlen < 8)
{
return(fatal);
}
if (main.sp < 4) /* No space for frame. */
{
Text.print_string("Save-file has too much stack (and I can't cope).\n");
return(fatal);
}
/* Read PC, procedure flag and formal param count. */
if (!read_long(svf, out tmpl))
{
return(fatal);
}
y = (int)(tmpl & 0x0F); /* Number of formals. */
tmpw = (zword)(y << 8);
/* Read result variable. */
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
/* Check the procedure flag... */
if ((tmpl & 0x10) > 0)
{
tmpw |= 0x1000; /* It's a procedure. */
tmpl >>= 8; /* Shift to get PC value. */
}
else
{
/* Functions have type 0, so no need to or anything. */
tmpl >>= 8; /* Shift to get PC value. */
--tmpl; /* Point at result byte. */
/* Sanity check on result variable... */
if (FastMem.ZMData[FastMem.zmp + tmpl] != (zbyte)x)
{
Text.print_string("Save-file has wrong variable number on stack (possibly wrong game version?)\n");
return(fatal);
}
}
main.stack[--main.sp] = (zword)(tmpl >> 9); /* High part of PC */
main.stack[--main.sp] = (zword)(tmpl & 0x1FF); /* Low part of PC */
main.stack[--main.sp] = (zword)(main.fp - 1); /* FP */
/* Read and process argument mask. */
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
++x; /* Should now be a power of 2 */
for (i = 0; i < 8; ++i)
{
if ((x & (1 << i)) > 0)
{
break;
}
}
if ((x ^ (1 << i)) > 0) /* Not a power of 2 */
{
Text.print_string("Save-file uses incomplete argument lists (which I can't handle)\n");
return(fatal);
}
// *--sp = tmpw | i;
main.stack[--main.sp] = (zword)(tmpw | i);
main.fp = main.sp; /* FP for next frame. */
/* Read amount of eval stack used. */
if (!read_word(svf, out tmpw))
{
return(fatal);
}
tmpw += (zword)y; /* Amount of stack + number of locals. */
// if (sp - stack <= tmpw) {
if (main.sp <= tmpw)
{
Text.print_string("Save-file has too much stack (and I can't cope).\n");
return(fatal);
}
if (currlen < tmpw * 2)
{
return(fatal);
}
for (i = 0; i < tmpw; ++i)
{
if (!read_word(svf, out main.stack[--main.sp]))
{
return(fatal);
}
}
currlen -= (zword)(tmpw * 2);
}
/* End of `Stks' processing... */
break;
/* Any more special chunk types must go in HERE or ABOVE. */
/* `CMem' compressed memory chunk; uncompress it. */
case 1129145709: // CMem
if ((progress & GOT_MEMORY) == 0) /* Don't complain if two. */
{
stf.Position = 0; // (void) fseek (stf, 0, SEEK_SET);
i = 0; /* Bytes written to data area. */
for (; currlen > 0; --currlen)
{
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
if (x == 0) /* Start run. */
{
/* Check for bogus run. */
if (currlen < 2)
{
Text.print_string("File contains bogus `CMem' chunk.\n");
for (; currlen > 0; --currlen)
{
svf.ReadByte(); /* Skip rest. */
}
currlen = 1;
i = 0xFFFF;
break; /* Keep going; may be a `UMem' too. */
}
/* Copy story file to memory during the run. */
--currlen;
if ((x = svf.ReadByte()) == -1)
{
return(fatal);
}
for (; x >= 0 && i < main.h_dynamic_size; --x, ++i)
{
if ((y = stf.ReadByte()) == -1)
{
return(fatal);
}
else
{
FastMem.ZMData[FastMem.zmp + i] = (zbyte)y;
}
}
}
else /* Not a run. */
{
if ((y = stf.ReadByte()) == -1)
{
return(fatal);
}
FastMem.ZMData[FastMem.zmp + i] = (zbyte)(x ^ y);
++i;
}
/* Make sure we don't load too much. */
if (i > main.h_dynamic_size)
{
Text.print_string("warning: `CMem' chunk too long!\n");
for (; currlen > 1; --currlen)
{
svf.ReadByte(); /* Skip rest. */
}
break; /* Keep going; there may be a `UMem' too. */
}
}
/* If chunk is short, assume a run. */
for (; i < main.h_dynamic_size; ++i)
{
if ((y = stf.ReadByte()) == -1)
{
return(fatal);
}
else
{
FastMem.ZMData[FastMem.zmp + i] = (zbyte)y;
}
}
if (currlen == 0)
{
progress |= GOT_MEMORY; /* Only if succeeded. */
}
break;
}
goto default;
/* Fall right thru (to default) if already GOT_MEMORY */
/* `UMem' uncompressed memory chunk; load it. */
case 1431135597: // ID_UMem:
if ((progress & GOT_MEMORY) == 0) /* Don't complain if two. */
{
/* Must be exactly the right size. */
if (currlen == main.h_dynamic_size)
{
byte[] buffer = new byte[currlen];
int read = svf.Read(FastMem.ZMData, (int)FastMem.zmp, (int)currlen);
if (read == currlen)
{
progress |= GOT_MEMORY; /* Only on success. */
break;
}
//if (fread(zmp, currlen, 1, svf) == 1) {
//}
}
else
{
Text.print_string("`UMem' chunk wrong size!\n");
}
/* Fall into default action (skip chunk) on errors. */
}
goto default;
/* Fall thru (to default) if already GOT_MEMORY */
/* Unrecognised chunk type; skip it. */
default:
// (void) fseek (svf, currlen, SEEK_CUR); /* Skip chunk. */
svf.Position += currlen;
break;
}
if (skip > 0)
{
svf.ReadByte(); /* Skip pad byte. */
}
}
/*
* We've reached the end of the file. For the restoration to have been a
* success, we must have had one of each of the required chunks.
*/
if ((progress & GOT_HEADER) == 0)
{
Text.print_string("error: no valid header (`IFhd') chunk in file.\n");
}
if ((progress & GOT_STACK) == 0)
{
Text.print_string("error: no valid stack (`Stks') chunk in file.\n");
}
if ((progress & GOT_MEMORY) == 0)
{
Text.print_string("error: no valid memory (`CMem' or `UMem') chunk in file.\n");
}
return((ushort)(progress == GOT_ALL ? 2 : fatal));
}