newlib-cygwin/libgloss/riscv/semihost-sys_read.c

33 lines
676 B
C

/*
* Copyright (C) 2020 Embecosm Limited
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <machine/syscall.h>
#include <errno.h>
#include <sys/types.h>
#include "semihost_syscall.h"
#include "semihost_fdtable.h"
/* Read from a file. */
ssize_t _read (int file, void *ptr, size_t len)
{
struct fdentry *fd =__get_fdentry (file);
long data_block[3];
long res;
if (fd == NULL)
return -1;
data_block[0] = fd->handle;
data_block[1] = (long) ptr;
data_block[2] = len;
res = syscall_errno (SEMIHOST_read, data_block);
if (res >= 0)
{
ssize_t bytes_read = len - res;
fd->pos += bytes_read;
return bytes_read;
}
return -1;
}