aboutsummaryrefslogtreecommitdiff
path: root/hw
diff options
context:
space:
mode:
authorPeter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>2012-08-01 20:26:12 +1000
committerPeter Crosthwaite <peter.crosthwaite@xilinx.com>2012-10-10 11:13:32 +1000
commita3578d4a51250365fb7f048e8154942a2659cc4a (patch)
tree37bfcfe61da751e12477b1ea7ae51a6d42b7799f /hw
parent8120e7144b4007d26531835c7b6bc2b40a736cd2 (diff)
downloadqemu-a3578d4a51250365fb7f048e8154942a2659cc4a.zip
qemu-a3578d4a51250365fb7f048e8154942a2659cc4a.tar.gz
qemu-a3578d4a51250365fb7f048e8154942a2659cc4a.tar.bz2
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>
Diffstat (limited to 'hw')
-rw-r--r--hw/Makefile.objs1
-rw-r--r--hw/fifo.c78
-rw-r--r--hw/fifo.h99
3 files changed, 178 insertions, 0 deletions
diff --git a/hw/Makefile.objs b/hw/Makefile.objs
index b59c749..66abbb2 100644
--- a/hw/Makefile.objs
+++ b/hw/Makefile.objs
@@ -35,6 +35,7 @@ common-obj-$(CONFIG_APPLESMC) += applesmc.o
common-obj-$(CONFIG_SMARTCARD) += ccid-card-passthru.o
common-obj-$(CONFIG_SMARTCARD_NSS) += ccid-card-emulated.o
common-obj-$(CONFIG_I8259) += i8259_common.o i8259.o
+common-obj-y += fifo.o
# PPC devices
common-obj-$(CONFIG_PREP_PCI) += prep_pci.o
diff --git a/hw/fifo.c b/hw/fifo.c
new file mode 100644
index 0000000..68a955a
--- /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()
+ }
+};
diff --git a/hw/fifo.h b/hw/fifo.h
new file mode 100644
index 0000000..f23890a
--- /dev/null
+++ b/hw/fifo.h
@@ -0,0 +1,99 @@
+#ifndef FIFO_H
+#define FIFO_H
+
+#include "hw.h"
+
+typedef struct {
+ /* All fields are private */
+ uint8_t *data;
+ uint32_t capacity;
+ uint32_t head;
+ uint32_t num;
+} Fifo8;
+
+/**
+ * fifo8_create:
+ * @fifo: struct Fifo8 to initialise with new FIFO
+ * @capacity: capacity of the newly created FIFO
+ *
+ * Create a FIFO of the specified size. Clients should call fifo8_destroy()
+ * when finished using the fifo. The FIFO is initially empty.
+ */
+
+void fifo8_create(Fifo8 *fifo, uint32_t capacity);
+
+/**
+ * fifo8_destroy:
+ * @fifo: FIFO to cleanup
+ *
+ * Cleanup a FIFO created with fifo8_create(). Frees memory created for FIFO
+ *storage. The FIFO is no longer usable after this has been called.
+ */
+
+void fifo8_destroy(Fifo8 *fifo);
+
+/**
+ * fifo8_push:
+ * @fifo: FIFO to push to
+ * @data: data byte to push
+ *
+ * Push a data byte to the FIFO. Behaviour is undefined if the FIFO is full.
+ * Clients are responsible for checking for fullness using fifo8_is_full().
+ */
+
+void fifo8_push(Fifo8 *fifo, uint8_t data);
+
+/**
+ * fifo8_pop:
+ * @fifo: fifo to pop from
+ *
+ * Pop a data byte from the FIFO. Behaviour is undefined if the FIFO is empty.
+ * Clients are responsible for checking for emptyness using fifo8_is_empty().
+ *
+ * Returns: The popped data byte.
+ */
+
+uint8_t fifo8_pop(Fifo8 *fifo);
+
+/**
+ * fifo8_reset:
+ * @fifo: FIFO to reset
+ *
+ * Reset a FIFO. All data is discarded and the FIFO is emptied.
+ */
+
+void fifo8_reset(Fifo8 *fifo);
+
+/**
+ * fifo8_is_empty:
+ * @fifo: FIFO to check
+ *
+ * Check if a FIFO is empty.
+ *
+ * Returns: True if the fifo is empty, false otherwise.
+ */
+
+bool fifo8_is_empty(Fifo8 *fifo);
+
+/**
+ * fifo8_is_full:
+ * @fifo: FIFO to check
+ *
+ * Check if a FIFO is full.
+ *
+ * Returns: True if the fifo is full, false otherwise.
+ */
+
+bool fifo8_is_full(Fifo8 *fifo);
+
+extern const VMStateDescription vmstate_fifo8;
+
+#define VMSTATE_FIFO8(_field, _state) { \
+ .name = (stringify(_field)), \
+ .size = sizeof(Fifo8), \
+ .vmsd = &vmstate_fifo8, \
+ .flags = VMS_STRUCT, \
+ .offset = vmstate_offset_value(_state, _field, Fifo8), \
+}
+
+#endif /* FIFO_H */