hw: Added generic FIFO API.

Added a FIFO API that can be used to create and operate byte FIFOs.

Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>

1 files changed, 78 insertions, 0 deletions

diff --git a/hw/fifo.c b/hw/fifo.c
new file mode 100644
index 0000000000..68a955a77b
--- /dev/null
+++ b/hw/fifo.c
@@ -0,0 +1,78 @@
+/*
+ * Generic FIFO component, implemented as a circular buffer.
+ *
+ * Copyright (c) 2012 Peter A. G. Crosthwaite
+ *
+ * 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
+ * 2 of the License, or (at your option) any later version.
+ *
+ * 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 "fifo.h"
+
+void fifo8_create(Fifo8 *fifo, uint32_t capacity)
+{
+    fifo->data = g_new(uint8_t, capacity);
+    fifo->capacity = capacity;
+    fifo->head = 0;
+    fifo->num = 0;
+}
+
+void fifo8_destroy(Fifo8 *fifo)
+{
+    g_free(fifo->data);
+}
+
+void fifo8_push(Fifo8 *fifo, uint8_t data)
+{
+    if (fifo->num == fifo->capacity) {
+        abort();
+    }
+    fifo->data[(fifo->head + fifo->num) % fifo->capacity] = data;
+    fifo->num++;
+}
+
+uint8_t fifo8_pop(Fifo8 *fifo)
+{
+    uint8_t ret;
+
+    if (fifo->num == 0) {
+        abort();
+    }
+    ret = fifo->data[fifo->head++];
+    fifo->head %= fifo->capacity;
+    fifo->num--;
+    return ret;
+}
+
+void fifo8_reset(Fifo8 *fifo)
+{
+    fifo->num = 0;
+}
+
+bool fifo8_is_empty(Fifo8 *fifo)
+{
+    return (fifo->num == 0);
+}
+
+bool fifo8_is_full(Fifo8 *fifo)
+{
+    return (fifo->num == fifo->capacity);
+}
+
+const VMStateDescription vmstate_fifo8 = {
+    .name = "Fifo8",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField[]) {
+        VMSTATE_VBUFFER_UINT32(data, Fifo8, 1, NULL, 0, capacity),
+        VMSTATE_UINT32(head, Fifo8),
+        VMSTATE_UINT32(num, Fifo8),
+        VMSTATE_END_OF_LIST()
+    }
+};