//******************************************************************************
/// _read - read a file descriptor.
int _read(int file, char *buf, int len)
{
// stdin reads from the UART by default
if (file == STDIN_FILENO)
{
int i;
int seen_newline = 0;
// read data
for(i = 0; i < len; i++)
{
int s, c;
// return if nothing is available and we already have a full line
__PATMOS_UART_STATUS(s);
if ((s & (__PATMOS_UART_DAV | __PATMOS_UART_PAE)) == 0 && seen_newline)
{
break;
}
// wait for data to be available from the UART
while ((s & (__PATMOS_UART_DAV | __PATMOS_UART_PAE)) == 0)
{
__PATMOS_UART_STATUS(s);
}
// simulator signals EOF via parity error
if ((s & __PATMOS_UART_PAE) != 0) {
break;
}
// read the data from the UART.
__PATMOS_UART_RD_DATA(c);
// copy data into the given buffer.
*buf++ = c & 0xff;
// stdin is usually line buffered, so stop reading on newline
if (c == '\n')
{
seen_newline = 1;
}
}
// keep track of offset for lseek
__patmos_stdin_offset += i;
// clear error code and return
errno = 0;
return i;
}
// TODO: implement for simulator target
errno = EBADF;
return -1;
}
//******************************************************************************
/// _lseek - seek position for a file descriptor.
int _lseek(int fd, off_t offset, int whenceq)
{
// For stdin and (positive) seek relative to current pos, we just consume bytes
if (fd == STDIN_FILENO) {
int curoff;
switch (whenceq) {
case SEEK_SET: curoff = offset - __patmos_stdin_offset; break;
case SEEK_CUR: curoff = offset; break;
default:
// We do not support SEEK_END for now
errno = EINVAL;
return -1;
}
if (curoff < 0) {
// We do not support seeking backwards
errno = EINVAL;
return -1;
}
int i;
// consume data from UART
for(i = 0; i < curoff; i++)
{
int s, c;
// wait for data to be available from the UART
do
{
__PATMOS_UART_STATUS(s);
} while((s & (__PATMOS_UART_DAV | __PATMOS_UART_PAE)) == 0);
// reached EOF?
if ((s & __PATMOS_UART_PAE) == 0)
{
// read the data from the UART.
__PATMOS_UART_RD_DATA(c);
}
else
{
// signal EOF
errno = EINVAL;
return -1;
}
}
// successful, update offset
__patmos_stdin_offset += curoff;
return __patmos_stdin_offset;
}
// TODO: implement for simulator target
errno = EBADF;
return -1;
}
/*
* console_inbyte_nonblocking
*
* This routine polls for a character.
*/
int console_inbyte_nonblocking( int port )
{
int s, c;
/* wait for data to be available from the UART */
do
{
__PATMOS_UART_STATUS(s);
} while((s & (__PATMOS_UART_DAV | __PATMOS_UART_PAE)) == 0);
/* read the data from the UART */
__PATMOS_UART_RD_DATA(c);
return c;
}
/*
* console_outbyte_polled
*
* This routine transmits a character using polling.
*/
void console_outbyte_polled(
int port,
unsigned char ch
)
{
int s;
/*
* Wait for the UART to be ready for transmission
*/
do
{
__PATMOS_UART_STATUS(s);
} while((s & __PATMOS_UART_TRE) == 0);
/*
* Write data to the UART
*/
__PATMOS_UART_WR_DATA(ch);
}
