Initial commit

engines/glk/alan3/stack.cpp

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "glk/alan3/stack.h"
+#include "glk/alan3/glkio.h"
+#include "glk/alan3/types.h"
+#include "glk/alan3/memory.h"
+#include "glk/alan3/options.h"
+#include "glk/alan3/syserr.h"
+
+namespace Glk {
+namespace Alan3 {
+
+/*======================================================================*/
+Stack createStack(int size) {
+	StackStructure *theStack = NEW(StackStructure);
+
+	theStack->stack = (Aword *)allocate(size * sizeof(Aptr));
+	theStack->stackSize = size;
+	theStack->framePointer = -1;
+
+	return theStack;
+}
+
+
+/*======================================================================*/
+void deleteStack(Stack theStack) {
+	if (theStack == nullptr)
+		syserr("deleting a NULL stack");
+
+	deallocate(theStack->stack);
+	deallocate(theStack);
+}
+
+
+/*======================================================================*/
+int stackDepth(Stack theStack) {
+	return theStack->stackp;
+}
+
+
+/*======================================================================*/
+void dumpStack(Stack theStack) {
+	int i;
+
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	printf("[");
+	for (i = 0; i < theStack->stackp; i++)
+		printf("%ld ", (unsigned long) theStack->stack[i]);
+	printf("]");
+	if (!traceInstructionOption && !tracePushOption)
+		printf("\n");
+}
+
+
+/*======================================================================*/
+void push(Stack theStack, Aptr i) {
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	if (theStack->stackp == theStack->stackSize)
+		syserr("Out of stack space.");
+	theStack->stack[(theStack->stackp)++] = i;
+}
+
+
+/*======================================================================*/
+Aptr pop(Stack theStack) {
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	if (theStack->stackp == 0)
+		syserr("Stack underflow.");
+	return theStack->stack[--(theStack->stackp)];
+}
+
+
+/*======================================================================*/
+Aptr top(Stack theStack) {
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	return theStack->stack[theStack->stackp - 1];
+}
+
+
+/* The AMACHINE Block Frames */
+
+/*======================================================================*/
+void newFrame(Stack theStack, Aint noOfLocals) {
+	int n;
+
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	push(theStack, theStack->framePointer);
+	theStack->framePointer = theStack->stackp;
+	for (n = 0; n < noOfLocals; n++)
+		push(theStack, 0);
+}
+
+
+/*======================================================================*/
+/* Local variables are numbered 1 and up and stored on their index-1 */
+Aptr getLocal(Stack theStack, Aint framesBelow, Aint variableNumber) {
+	int frame;
+	int frameCount;
+
+	if (variableNumber < 1)
+		syserr("Reading a non-existing block-local variable.");
+
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	frame = theStack->framePointer;
+
+	if (framesBelow != 0)
+		for (frameCount = framesBelow; frameCount != 0; frameCount--)
+			frame = theStack->stack[frame - 1];
+
+	return theStack->stack[frame + variableNumber - 1];
+}
+
+
+/*======================================================================*/
+void setLocal(Stack theStack, Aint framesBelow, Aint variableNumber, Aptr value) {
+	int frame;
+	int frameCount;
+
+	if (variableNumber < 1)
+		syserr("Writing a non-existing block-local variable.");
+
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	frame = theStack->framePointer;
+	if (framesBelow != 0)
+		for (frameCount = framesBelow; frameCount != 0; frameCount--)
+			frame = theStack->stack[frame - 1];
+
+	theStack->stack[frame + variableNumber - 1] = value;
+}
+
+/*======================================================================*/
+void endFrame(Stack theStack) {
+	if (theStack == nullptr)
+		syserr("NULL stack not supported anymore");
+
+	theStack->stackp = theStack->framePointer;
+	theStack->framePointer = pop(theStack);
+}
+
+} // End of namespace Alan3
+} // End of namespace Glk