添加一些关于midi播放的项目

Midi/music-box-nv32-master/gcc-stdio-retarget.c

@@ -0,0 +1,117 @@
+#include <errno.h>
+#include <stdio.h>
+#include <sys/stat.h>
+#include <sys/unistd.h>
+#include "common.h"
+#include "uart.h"
+
+#undef errno
+extern int errno;
+
+#define OUTPUT_PRINTF 0
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+
+void stdio_setup(void)
+{
+#if OUTPUT_PRINTF
+    // Turn off buffers, so I/O occurs immediately
+    setvbuf(stdin, NULL, _IONBF, 0);
+    setvbuf(stdout, NULL, _IONBF, 0);
+    setvbuf(stderr, NULL, _IONBF, 0);
+#endif
+}
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+
+int _read(int file, char *data, int len)
+{
+    int bytes_read = 0;
+
+#if OUTPUT_PRINTF
+    if (file != STDIN_FILENO)
+    {
+        errno = EBADF;
+        return -1;
+    }
+
+    for (bytes_read = 0; bytes_read < len; bytes_read++)
+    {
+        *data = (char)UART_GetChar(TERM_PORT);
+        data++;
+    }
+#endif
+    return bytes_read;
+}
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+
+int _write(int file, char *data, int len)
+{
+    int bytes_written = 0;
+#if OUTPUT_PRINTF
+    if ((file != STDOUT_FILENO) && (file != STDERR_FILENO))
+    {
+        errno = EBADF;
+        return -1;
+    }
+
+    for (bytes_written = 0; bytes_written < len; bytes_written++)
+    {
+        UART_PutChar(TERM_PORT, *data);
+        data++;
+    }
+#endif
+    return bytes_written;
+}
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+
+int _close(int file)
+{
+    return -1;
+}
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+
+int _lseek(int file, int ptr, int dir)
+{
+    return 0;
+}
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+
+int _fstat(int file, struct stat *st)
+{
+    st->st_mode = S_IFCHR;
+    return 0;
+}
+
+/******************************************************************************
+ *
+ ******************************************************************************/
+
+int _isatty(int file)
+{
+    if ((file == STDOUT_FILENO) ||
+        (file == STDIN_FILENO) ||
+        (file == STDERR_FILENO))
+    {
+        return 1;
+    }
+
+    errno = EBADF;
+    return 0;
+}