Add mapper 594 with expansion sound.

src/boards/fifo.c

@@ -0,0 +1,43 @@
+#include "mapinc.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include "fifo.h"
+
+size_t FIFO_size (FIFO *fifo) {
+	fifo->front %= fifo->capacity;
+	fifo->back %= fifo->capacity;
+	return (fifo->back -fifo->front +fifo->capacity) %fifo->capacity;
+}
+
+uint8 FIFO_halfFull (FIFO *fifo) {
+	return FIFO_size(fifo) >= fifo->capacity /2;
+}
+
+int FIFO_retrieve (FIFO *fifo) {
+	fifo->front %= fifo->capacity;
+	return FIFO_size(fifo)? fifo->data[fifo->front++]: 0;
+}
+
+void FIFO_add (FIFO *fifo, uint8 value) {
+	fifo->back %= fifo->capacity;
+	if (FIFO_size(fifo) <fifo->capacity) fifo->data[fifo->back++] = value;
+}
+
+void FIFO_reset (FIFO *fifo) {
+	fifo->front = fifo->back = 0;
+}
+
+void FIFO_init (FIFO *fifo, size_t newCapacity) {
+	fifo->capacity = newCapacity;
+	fifo->data = (uint8*)FCEU_gmalloc(newCapacity);
+	AddExState(fifo->data, fifo->capacity, 0, "FIFD");
+	AddExState(&fifo->front, 2, 0, "FIFF");
+	AddExState(&fifo->back, 2, 0, "FIFB");
+}
+
+void FIFO_close (FIFO *fifo) {
+	if (fifo->data) {
+		free(fifo->data);
+		fifo->data = NULL;
+	}
+}