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/* cygmon.c -- Glue code for linking apps to run on top of Cygmon.

 *

 * Copyright (c) 1998, 1999, 2000 Red Hat, Inc.

 *

 * The authors hereby grant permission to use, copy, modify, distribute,

 * and license this software and its documentation for any purpose, provided

 * that existing copyright notices are retained in all copies and that this

 * notice is included verbatim in any distributions. No written agreement,

 * license, or royalty fee is required for any of the authorized uses.

 * Modifications to this software may be copyrighted by their authors

 * and need not follow the licensing terms described here, provided that

 * the new terms are clearly indicated on the first page of each file where

 * they apply.

 */

#include "syscall.h"

int

write ( int file,

        char *buf,

        int nbytes)

{

  return sysCall(SYS_write, file, (unsigned long)buf, nbytes);

}

int

read (int file,

      char *buf,

      int nbytes)

{

  return sysCall(SYS_read, file, (unsigned long)buf, nbytes);

}

int

outbyte (unsigned char c)

{

  return sysCall(SYS_write, 0, (unsigned long)&c, 1);

}

unsigned char

inbyte (void)

{

  char c;

  sysCall(SYS_read, 0, (unsigned long)&c, 1);

  return c;

}

/* Structure filled in by get_mem_info.  Only the size field is

   actually used (by sbrk), so the others aren't even filled in.  */

struct s_mem

{

  unsigned int size;

  unsigned int icsize;

  unsigned int dcsize;

};

// Perform a system call.

// Unused parameters should be set to 0.

int sysCall(unsigned long func, unsigned long p1, unsigned long p2, unsigned long p3)

{

  int ret = 0;

  asm volatile ( "              \n\

          move $4, %1           \n\

          move $5, %2           \n\

          move $6, %3           \n\

          move $7, %4           \n\

          syscall               \n\

          nop                   \n\

          move %0, $2" : "=r"(ret) : "r"(func), "r"(p1), "r"(p2), "r"(p3));

  return ret;

}

// These need to be kept in sync with the definitions in Cygmon.

#define SYS_meminfo     1001

void *

get_mem_info (mem)

     struct s_mem *mem;

{

  unsigned long totmem = 0, topmem = 0;

  int numbanks;

  numbanks = sysCall(SYS_meminfo, (unsigned long)&totmem, (unsigned long)&topmem, 0);

  mem->size = totmem;

  return (void*)topmem;

}