/**
***************************************************************************
**  File        : syscalls.c
**  Abstract    : System Workbench Minimal System calls file
**                modified by Aegean Associates, Inc. (AO)
**
** 		  For more information about which c-functions
**                need which of these low level functions please
**                consult the Newlib libc-manual
**
**  Distribution: The file is distributed "as is", without any 
**                warranty of any kind.
***************************************************************************
** <h2><center>&copy; COPYRIGHT(c) 2014 Ac6</center></h2>
**
** Redistribution and use in source and binary forms, with or without modi-
** fication, are permitted provided that the following conditions are met:
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. Neither the name of Ac6 nor the names of its contributors may be 
**    used to endorse or promote products derived from this software
**    without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE  COPYRIGHT
** HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
** TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
** PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
** LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
** NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE  USE OF THIS
** SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
***************************************************************************
*/

#include <sys/stat.h>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
#include <signal.h>
#include <time.h>
#include <sys/time.h>
#include <sys/times.h>

extern int errno;
extern int __io_putchar(int ch) __attribute__((weak));
extern int __io_getchar(void) __attribute__((weak));

register char * stack_ptr asm("sp");

char *__env[1] = { 0 };
char **environ = __env;

void initialise_monitor_handles()
{

}

int _getpid(void)
{
    return 1;
}

int _kill(int pid, int sig)
{
    errno = EINVAL;
    return -1;
}

void _exit (int status)
{
    _kill(status, -1);
    while (1) {}  /* hang here */
}

int _read (int file, char *ptr, int len)
{
    int i;    
    for (i = len; i > 0; i--)
	*ptr++ = __io_getchar();
    return len;
}

int _write(int file, char *ptr, int len)
{
    int i;
    for (i = len; i > 0; i--)
	__io_putchar(*ptr++);
    return len;
}

#if 1  /* ###AO### reworked for Marlin */
extern char end asm("end");
char * __brkval;  // declared global for Marlin

caddr_t _sbrk(int incr)
{
    char * bv;

    if (! __brkval)
	__brkval = &end;
 
    bv = __brkval;
    if ((__brkval + incr) > stack_ptr) {
	errno = ENOMEM;
	return (caddr_t) -1;
    }
    __brkval += incr;
    return (caddr_t) bv;
}
#else
caddr_t _sbrk(int incr)
{
    extern char end asm("end");
    static char *heap_end;
    char *prev_heap_end;

    if (heap_end == 0)
	heap_end = &end;

    prev_heap_end = heap_end;
    if (heap_end + incr > stack_ptr) {
	write(1, "Heap and stack collision\n", 25);
	abort();
	errno = ENOMEM;
	return (caddr_t) -1;
    }
    
    heap_end += incr;
    return (caddr_t) prev_heap_end;
}
#endif

int _close(int file)
{
    return -1;
}

int _fstat(int file, struct stat *st)
{
    st->st_mode = S_IFCHR;
    return 0;
}

int _isatty(int file)
{
    return 1;
}

int _lseek(int file, int ptr, int dir)
{
    return 0;
}

int _open(char *path, int flags, ...)
{
    /* always fail */
    return -1;
}

int _wait(int *status)
{
    errno = ECHILD;
    return -1;
}

int _unlink(char *name)
{
    errno = ENOENT;
    return -1;
}

int _times(struct tms *buf)
{
    return -1;
}

int _stat(char *file, struct stat *st)
{
    st->st_mode = S_IFCHR;
    return 0;
}

int _link(char *old, char *new)
{
    errno = EMLINK;
    return -1;
}

int _fork(void)
{
    errno = EAGAIN;
    return -1;
}

int _execve(char *name, char **argv, char **env)
{
    errno = ENOMEM;
    return -1;
}
