From 9435a85605d7efc75642491c85b0942bd558fcec Mon Sep 17 00:00:00 2001
From: xengineering <mail2xengineering@protonmail.com>
Date: Sun, 25 Oct 2020 12:49:35 +0100
Subject: Add usart_irq Code

---
 libraries/fifo.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 libraries/fifo.c

(limited to 'libraries/fifo.c')

diff --git a/libraries/fifo.c b/libraries/fifo.c
new file mode 100644
index 0000000..faa9fc4
--- /dev/null
+++ b/libraries/fifo.c
@@ -0,0 +1,66 @@
+
+
+#include "fifo.h"
+
+
+void fifo_init(FIFO *fifo, uint16_t bufferlength)
+{
+    fifo->buffer_ptr = calloc(bufferlength, sizeof(uint8_t));
+    fifo->read_index = 0;
+    fifo->write_index = 0;
+    fifo->bufferlength = bufferlength;
+}
+
+void fifo_deinit(FIFO *fifo)
+{
+    free(fifo->buffer_ptr);
+}
+
+uint16_t fifo_get_buffersize(FIFO *fifo)
+{
+    return fifo->bufferlength;
+}
+
+uint16_t fifo_bytes_available(FIFO *fifo)
+{
+    if (fifo->write_index > fifo->read_index){
+        return (fifo->write_index - fifo->read_index);
+    }
+    else if (fifo->write_index < fifo->read_index){
+        return (fifo_get_buffersize(fifo) - (fifo->read_index - fifo->write_index));
+    }
+    else {  // read_index == write_index
+        return 0;
+    }
+}
+
+//uint16_t fifo_lines_available(FIFO *fifo){}
+
+void fifo_move_read_index(FIFO *fifo)
+{
+    fifo->read_index++;
+    fifo->read_index %= fifo_get_buffersize(fifo);
+}
+
+void fifo_move_write_index(FIFO *fifo)
+{
+    fifo->write_index++;
+    fifo->write_index %= fifo_get_buffersize(fifo);
+}
+
+void fifo_get_byte(FIFO *fifo, uint8_t *data_sink)
+{
+    if(fifo_bytes_available(fifo)){
+        *data_sink = fifo->buffer_ptr[fifo->read_index];
+        fifo_move_read_index(fifo);
+    }
+}
+
+void fifo_put_byte(FIFO *fifo, uint8_t *data_source)
+{
+    fifo->buffer_ptr[fifo->write_index] = *data_source;
+    fifo_move_write_index(fifo);
+    if(fifo->read_index == fifo->write_index){  // buffer overflow case
+        fifo_move_read_index(fifo);
+    }
+}
-- 
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