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//printf needs following syscalls: sbrk write close fstat isatty lseek read
//
#include <sys/stat.h>
#include <string.h>
#include <stdint.h>
#include "../fs/fs.h"
static int preread;
static int alloc;
easywrite(char *c);
// init syscalls
void syscalls_init()
{
// TODO dynamic!
alloc=0x300000;
}
// generic syscall interface!
int syscall(int call, int p1, int p2, int p3)
{
int ebx; // will hold return value;
asm("pusha");
// select syscall
asm("mov %0, %%eax"::"m"(call));
// pass params
asm("mov %0,%%edx"::"m"(p1));
asm("mov %0,%%ecx"::"m"(p2));
asm("mov %0,%%ebx"::"m"(p3));
// interrrupt
asm("int $0x80");
// get return value
asm("mov %%ebx, %0": "=b" (ebx));
asm("popa");
return ebx;
}
//
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)
{
if(dir==0)preread=ptr;
else{ puts("other modes unsupported sorry"); while(1);}
return preread;
}
int read(int file, char *ptr, int len)
{
return syscall(62,file,ptr,len);
}
int readdir(const char *name,fs_dirent *dirs,int max)
{
return syscall(63,name,dirs,max);
}
int open(const char *name, int flags, int mode)
{
return name;
}
int write(int file, char *ptr, int len)
{
return syscall(61,file,ptr,len);
}
int execve(char *name, char **argv, char **env)
{
return syscall(64,name,argv,env);
}
caddr_t sbrk(int incr)
{
// easywrite("syscall: sbrk!!\n");
int oldalloc=alloc;
alloc+=incr;
return oldalloc;
/*
extern char end;
// char _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 ();
}
heap_end += incr;
return (caddr_t) prev_heap_end;
*/
}
//
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