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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;
}
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