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-rw-r--r--engines/tinsel/pcode.cpp125
-rw-r--r--engines/tinsel/pcode.h14
2 files changed, 112 insertions, 27 deletions
diff --git a/engines/tinsel/pcode.cpp b/engines/tinsel/pcode.cpp
index a9c6f43d85..ac7bf9970f 100644
--- a/engines/tinsel/pcode.cpp
+++ b/engines/tinsel/pcode.cpp
@@ -112,6 +112,21 @@ static INT_CONTEXT *icList = 0;
static uint32 hMasterScript;
+//----------------- SCRIPT BUGS WORKAROUNDS --------------
+
+const byte fragment1[] = {(byte)OP_ZERO, (byte) OP_GSTORE | OPSIZE16, 206, 0};
+const int fragment1_size = 4;
+
+const WorkaroundEntry workaroundList[] = {
+ // Global 206 in DW1-SCN is whether Rincewind is trying to take the book back to the present.
+ // In the GRA version, it was global 373, and was reset when he is returned to the past, but
+ // was forgotten in the SCN version, so this ensures the flag is properly reset
+ {TINSEL_V1, true, 427942095, 1, fragment1_size, fragment1},
+ {TINSEL_V0, false, 0, 0, 0, NULL}
+};
+
+//----------------- LOCAL GLOBAL DATA --------------------
+
/**
* Keeps the code array pointer up to date.
*/
@@ -398,38 +413,93 @@ void SaveInterpretContexts(INT_CONTEXT *sICInfo) {
}
/**
- * Fetch (and sign extend, if necessary) a 8/16/32 bit value from the code
- * stream and advance the instruction pointer accordingly.
+ * Fetches up to 4 bytes from the code script
*/
-static int32 Fetch(byte opcode, byte *code, int &ip) {
- int32 tmp;
- if (TinselV0) {
- // Fetch a 32 bit value.
- tmp = (int32)READ_LE_UINT32(code + ip++ * 4);
- } else if (opcode & OPSIZE8) {
+static int32 GetBytes(const byte *scriptCode, const WorkaroundEntry* &wkEntry, int &ip, uint numBytes) {
+ assert(numBytes <= 4 && numBytes != 3);
+ const byte *code = scriptCode;
+
+ if (wkEntry != NULL) {
+ if (ip >= wkEntry->numBytes) {
+ // Finished the workaround
+ ip = wkEntry->ip;
+ wkEntry = NULL;
+ } else {
+ code = wkEntry->script;
+ }
+ }
+
+ uint32 tmp;
+ switch (numBytes) {
+ case 0:
+ // Instruction byte
+ tmp = code[ip++ * (TinselV0 ? 4 : 1)];
+ break;
+ case 1:
// Fetch and sign extend a 8 bit value to 32 bits.
- tmp = *(int8 *)(code + ip);
- ip += 1;
- } else if (opcode & OPSIZE16) {
+ tmp = (int8)code[ip++];
+ break;
+ case 2:
// Fetch and sign extend a 16 bit value to 32 bits.
tmp = (int16)READ_LE_UINT16(code + ip);
ip += 2;
- } else {
- // Fetch a 32 bit value.
- tmp = (int32)READ_LE_UINT32(code + ip);
- ip += 4;
+ break;
+ default:
+ if (TinselV0)
+ tmp = (int32)READ_LE_UINT32(code + ip++ * 4);
+ else {
+ tmp = (int32)READ_LE_UINT32(code + ip);
+ ip += 4;
+ }
+ break;
}
+
return tmp;
}
/**
+ * Fetch (and sign extend, if necessary) a 8/16/32 bit value from the code
+ * stream and advance the instruction pointer accordingly.
+ */
+static int32 Fetch(byte opcode, const byte *code, const WorkaroundEntry* &wkEntry, int &ip) {
+ if (TinselV0)
+ // Fetch a 32 bit value.
+ return GetBytes(code, wkEntry, ip, 4);
+ else if (opcode & OPSIZE8)
+ // Fetch and sign extend a 8 bit value to 32 bits.
+ return GetBytes(code, wkEntry, ip, 1);
+ else if (opcode & OPSIZE16)
+ return GetBytes(code, wkEntry, ip, 2);
+
+ return GetBytes(code, wkEntry, ip, 4);
+}
+
+/**
* Interprets the PCODE instructions in the code array.
*/
void Interpret(CORO_PARAM, INT_CONTEXT *ic) {
do {
int tmp, tmp2;
int ip = ic->ip;
- byte opcode = ic->code[ip++ * (TinselV0 ? 4 : 1)];
+ const WorkaroundEntry *wkEntry = ic->fragmentPtr;
+
+ if (wkEntry == NULL) {
+ // Check to see if a workaround fragment needs to be executed
+ for (wkEntry = workaroundList; wkEntry->script != NULL; ++wkEntry) {
+ if ((wkEntry->version == TinselVersion) &&
+ (wkEntry->hCode == ic->hCode) &&
+ (wkEntry->ip == ip) &&
+ (!TinselV1 || (wkEntry->scnFlag == ((_vm->getFeatures() & GF_SCNFILES) != 0)))) {
+ // Point to start of workaround fragment
+ ip = 0;
+ break;
+ }
+ }
+ if (wkEntry->script == NULL)
+ wkEntry = NULL;
+ }
+
+ byte opcode = (byte)GetBytes(ic->code, wkEntry, ip, 0);
if (TinselV0 && ((opcode & OPMASK) > OP_IMM))
opcode += 3;
@@ -447,7 +517,7 @@ void Interpret(CORO_PARAM, INT_CONTEXT *ic) {
case OP_FONT: // loads font handle onto stack
case OP_PAL: // loads palette handle onto stack
- ic->stack[++ic->sp] = Fetch(opcode, ic->code, ip);
+ ic->stack[++ic->sp] = Fetch(opcode, ic->code, wkEntry, ip);
break;
case OP_ZERO: // loads zero onto stack
@@ -464,31 +534,31 @@ void Interpret(CORO_PARAM, INT_CONTEXT *ic) {
case OP_LOAD: // loads local variable onto stack
- ic->stack[++ic->sp] = ic->stack[ic->bp + Fetch(opcode, ic->code, ip)];
+ ic->stack[++ic->sp] = ic->stack[ic->bp + Fetch(opcode, ic->code, wkEntry, ip)];
break;
case OP_GLOAD: // loads global variable onto stack
- tmp = Fetch(opcode, ic->code, ip);
+ tmp = Fetch(opcode, ic->code, wkEntry, ip);
assert(0 <= tmp && tmp < numGlobals);
ic->stack[++ic->sp] = pGlobals[tmp];
break;
case OP_STORE: // pops stack and stores in local variable
- ic->stack[ic->bp + Fetch(opcode, ic->code, ip)] = ic->stack[ic->sp--];
+ ic->stack[ic->bp + Fetch(opcode, ic->code, wkEntry, ip)] = ic->stack[ic->sp--];
break;
case OP_GSTORE: // pops stack and stores in global variable
- tmp = Fetch(opcode, ic->code, ip);
+ tmp = Fetch(opcode, ic->code, wkEntry, ip);
assert(0 <= tmp && tmp < numGlobals);
pGlobals[tmp] = ic->stack[ic->sp--];
break;
case OP_CALL: // procedure call
- tmp = Fetch(opcode, ic->code, ip);
+ tmp = Fetch(opcode, ic->code, wkEntry, ip);
//assert(0 <= tmp && tmp < codeSize); // TODO: Verify jumps are not out of bounds
ic->stack[ic->sp + 1] = 0; // static link
ic->stack[ic->sp + 2] = ic->bp; // dynamic link
@@ -499,7 +569,7 @@ void Interpret(CORO_PARAM, INT_CONTEXT *ic) {
case OP_LIBCALL: // library procedure or function call
- tmp = Fetch(opcode, ic->code, ip);
+ tmp = Fetch(opcode, ic->code, wkEntry, ip);
// NOTE: Interpret() itself is not using the coroutine facilities,
// but still accepts a CORO_PARAM, so from the outside it looks
// like a coroutine. In fact it may still acts as a kind of "proxy"
@@ -538,17 +608,17 @@ void Interpret(CORO_PARAM, INT_CONTEXT *ic) {
case OP_ALLOC: // allocate storage on stack
- ic->sp += (int32)Fetch(opcode, ic->code, ip);
+ ic->sp += (int32)Fetch(opcode, ic->code, wkEntry, ip);
break;
case OP_JUMP: // unconditional jump
- ip = Fetch(opcode, ic->code, ip);
+ ip = Fetch(opcode, ic->code, wkEntry, ip);
break;
case OP_JMPFALSE: // conditional jump
- tmp = Fetch(opcode, ic->code, ip);
+ tmp = Fetch(opcode, ic->code, wkEntry, ip);
if (ic->stack[ic->sp--] == 0) {
// condition satisfied - do the jump
ip = tmp;
@@ -557,7 +627,7 @@ void Interpret(CORO_PARAM, INT_CONTEXT *ic) {
case OP_JMPTRUE: // conditional jump
- tmp = Fetch(opcode, ic->code, ip);
+ tmp = Fetch(opcode, ic->code, wkEntry, ip);
if (ic->stack[ic->sp--] != 0) {
// condition satisfied - do the jump
ip = tmp;
@@ -660,6 +730,7 @@ void Interpret(CORO_PARAM, INT_CONTEXT *ic) {
// check for stack under-overflow
assert(ic->sp >= 0 && ic->sp < PCODE_STACK_SIZE);
ic->ip = ip;
+ ic->fragmentPtr = wkEntry;
} while (!ic->bHalt);
// make sure stack is unwound
diff --git a/engines/tinsel/pcode.h b/engines/tinsel/pcode.h
index 4bdfcf5626..fad50cdb9d 100644
--- a/engines/tinsel/pcode.h
+++ b/engines/tinsel/pcode.h
@@ -54,6 +54,17 @@ enum GSORT {
enum RESCODE {RES_WAITING, RES_FINISHED, RES_CUTSHORT};
+// The following structure is used to introduce bug fixes into the scripts used by the games
+
+struct WorkaroundEntry {
+ TinselEngineVersion version;
+ bool scnFlag; // Only applicable for Tinsel 1 (DW 1)
+ SCNHANDLE hCode; // Script to apply fragment to
+ int ip; // Script offset to run this fragment before
+ int numBytes; // Number of bytes in the script
+ const byte *script; // Instruction(s) to execute
+};
+
struct INT_CONTEXT {
// Elements for interpret context management
@@ -82,6 +93,9 @@ struct INT_CONTEXT {
RESCODE resumeCode;
RESUME_STATE resumeState;
+ // Used to store execution state within a script workaround fragment
+ const WorkaroundEntry *fragmentPtr;
+
void syncWithSerializer(Common::Serializer &s);
};
typedef INT_CONTEXT *PINT_CONTEXT;
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-15 22:32:30 +0000