mes/mlibc/libc-mes.c
Jan Nieuwenhuizen 4479540aed mescc: Put _start at top of mlibc.
* mlibc/libc-mes.c (_start): Move to top.
* mlibc/mini-libc-mes.c (_start): Likewise.
* module/mes/elf-util.mes (function-prefix): Update for _start == 0.
  (function-offset): Likewise.
2017-06-11 13:01:46 +02:00

391 lines
8 KiB
C

/* -*-comment-start: "//";comment-end:""-*-
* Mes --- Maxwell Equations of Software
* Copyright © 2016,2017 Jan Nieuwenhuizen <janneke@gnu.org>
*
* This file is part of Mes.
*
* Mes is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* Mes is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Mes. If not, see <http://www.gnu.org/licenses/>.
*/
int g_stdin = 0;
char **g_environment;
int _env ();
int exit ();
int main(int,char*[]);
int
_start ()
{
asm (".byte 0x89 0xe8"); // mov %ebp,%eax
asm (".byte 0x83 0xc0 0x08"); // add $0x8,%eax
asm (".byte 0x50"); // push %eax
asm (".byte 0x89 0xe8"); // mov %ebp,%eax
asm (".byte 0x83 0xc0 0x04"); // add $0x4,%eax
asm (".byte 0x0f 0xb6 0x00"); // movzbl (%eax),%eax
asm (".byte 0x50"); // push %eax
asm (".byte 0x89 0xe8"); // mov %ebp,%eax
asm (".byte 0x83 0xc0 0x04"); // add $0x4,%eax
asm (".byte 0x0f 0xb6 0x00"); // movzbl (%eax),%eax
asm (".byte 0x83 0xc0 0x03"); // add $0x3,%eax
asm (".byte 0xc1 0xe0 0x02"); // shl $0x2,%eax
asm (".byte 0x01 0xe8"); // add %ebp,%eax
asm (".byte 0x50"); // push %eax
g_environment = _env ();
asm (".byte 0x58");
int r = main ();
exit (r);
}
char **
_env (char **e)
{
return e;
}
void
exit ()
{
asm (".byte 0x8b 0x5d 0x08"); // mov 0x8(%ebp),%ebx
asm (".byte 0xb8 0x01 0x00 0x00 0x00"); // mov $0x1,%eax
asm (".byte 0xcd 0x80"); // int $0x80
}
void
read ()
{
asm (".byte 0x8b 0x5d 0x08"); // mov 0x8(%ebp),%ebx
asm (".byte 0x8b 0x4d 0x0c"); // mov 0xc(%ebp),%ecx
asm (".byte 0x8b 0x55 0x10"); // mov 0x10(%ebp),%edx
asm (".byte 0xb8 0x03 0x00 0x00 0x00"); // mov $0x3,%eax
asm (".byte 0xcd 0x80"); // int $0x80
}
void
write ()
{
asm (".byte 0x8b 0x5d 0x08"); // mov 0x8(%ebp),%ebx
asm (".byte 0x8b 0x4d 0x0c"); // mov 0xc(%ebp),%ecx
asm (".byte 0x8b 0x55 0x10"); // mov 0x10(%ebp),%edx
asm (".byte 0xb8 0x04 0x00 0x00 0x00"); // mov $0x4,%eax
asm (".byte 0xcd 0x80"); // int $0x80
}
void
open ()
{
asm (".byte 0x8b 0x5d 0x08"); // mov 0x8(%ebp),%ebx
asm (".byte 0x8b 0x4d 0x0c"); // mov 0xc(%ebp),%ecx
asm (".byte 0x8b 0x55 0x10"); // mov 0x10(%ebp),%edx
asm (".byte 0xb8 0x05 0x00 0x00 0x00"); // mov $0x5,%eax
asm (".byte 0xcd 0x80"); // int $0x80
}
void
access ()
{
asm (".byte 0x8b 0x5d 0x08"); // mov 0x8(%ebp),%ebx
asm (".byte 0x8b 0x4d 0x0c"); // mov 0xc(%ebp),%ecx
asm (".byte 0xb8 0x21 0x00 0x00 0x00"); // mov $0x21,%eax
asm (".byte 0xcd 0x80"); // int $0x80
}
void
brk ()
{
asm (".byte 0x8b 0x5d 0x08"); // mov 0x8(%ebp),%ebx
asm (".byte 0xb8 0x2d 0x00 0x00 0x00"); // mov $0x2d,%eax
asm (".byte 0xcd 0x80"); // int $0x80
}
void
fsync ()
{
asm (".byte 0x8b 0x5d 0x08"); // mov 0x8(%ebp),%ebx
asm (".byte 0xb8 0x76 0x00 0x00 0x00"); // mov $0x76,%eax
asm (".byte 0xcd 0x80"); // int $0x80
}
int
strlen (char const* s)
{
int i = 0;
while (s[i]) i++;
return i;
}
int
eputs (char const* s)
{
int i = strlen (s);
write (2, s, i);
return 0;
}
int
fputs (char const* s, int fd)
{
int i = strlen (s);
write (fd, s, i);
return 0;
}
int
puts (char const* s)
{
int i = strlen (s);
write (1, s, i);
return 0;
}
int
putchar (int c)
{
write (1, (char*)&c, 1);
return 0;
}
int
fputc (int c, int fd)
{
write (fd, (char*)&c, 1);
return 0;
}
void
assert_fail (char* s)
{
eputs ("assert fail: ");
eputs (s);
eputs ("\n");
//*((int*)0) = 0;
char *fail = s;
fail = 0;
*fail = 0;
}
int ungetc_char = -1;
char ungetc_buf[2];
int
getchar ()
{
char c;
int i;
if (ungetc_char == -1)
{
int r = read (g_stdin, &c, 1);
if (r < 1) return -1;
i = c;
}
else
{
//FIXME
//i = ungetc_buf[ungetc_char--];
i = ungetc_buf[ungetc_char];
//ungetc_char--;
ungetc_char = ungetc_char - 1;
}
if (i < 0) i += 256;
return i;
}
//#define assert(x) ((x) ? (void)0 : assert_fail (#x))
int
ungetc (int c, int fd)
{
//FIXME
//assert (ungetc_char < 2);
//assert (ungetc_char == -1 || ungetc_char < 2);
//FIXME
//ungetc_buf[++ungetc_char] = c;
ungetc_char++;
ungetc_buf[ungetc_char] = c;
return c;
}
int
strcmp (char const* a, char const* b)
{
while (*a && *b && *a == *b)
{
a++;b++;
}
return *a - *b;
}
char *
strcpy (char *dest, char const *src)
{
char *p = dest;
while (*src) *p++ = *src++;
*p = 0;
return dest;
}
char itoa_buf[10];
char const*
itoa (int x)
{
//static char itoa_buf[10];
//char *p = buf+9;
char *p = itoa_buf;
p += 9;
*p-- = 0;
//int sign = x < 0; // FIXME
int sign = 0;
if (x < 0) sign = 1;
if (sign)
x = -x;
do
{
*p-- = '0' + (x % 10);
x = x / 10;
} while (x);
if (sign && *(p + 1) != '0')
*p-- = '-';
return p+1;
}
int
isdigit (char c)
{
//return (c>='0') && (c<='9');
if (c>='0' && c<='9') return 1;
return 0;
}
int
atoi (char const *s)
{
int i = 0;
int sign = 1;
if (*s && *s == '-')
{
sign = -1;
s++;
}
while (isdigit (*s))
{
i *= 10;
i += (*s - '0');
s++;
}
return i * sign;
}
//void *g_malloc_base = 0;
char *g_malloc_base = 0;
//void *
int *
malloc (int size)
{
//void *p = brk (0);
char *p = 0;
p = brk (0);
if (!g_malloc_base) g_malloc_base = p;
brk (p+size);
return p;
}
//void *
int *
//realloc (void *p, int size)
realloc (int *p, int size)
{
brk (g_malloc_base + size);
return g_malloc_base;
}
int
strncmp (char const* a, char const* b, int length)
{
while (*a && *b && *a == *b && --length) {a++;b++;}
return *a - *b;
}
char **g_environment;
char *
getenv (char const* s)
{
char **p = g_environment;
p = *g_environment;
int length = strlen (s);
while (*p)
{
if (!strncmp (s, *p, length) && *(*p + length) == '=') return (*p + length + 1);
p++;
}
return 0;
}
#if 0
// !__MESC__
// FIXME: mes+nyacc parser bug here
// works fine with Guile, but let's keep a single input source
#define pop_va_arg \
asm (".byte 0x8b 0x45 0xfc"); /* mov -<0x4>(%ebp),%eax :va_arg */ \
asm (".byte 0xc1 0xe0 0x02"); /* shl $0x2,%eax */ \
asm (".byte 0x01 0xe8"); /* add %ebp,%eax */ \
asm (".byte 0x83 0xc0 0x0c"); /* add $0xc,%eax */ \
asm (".byte 0x8b 0x00"); /* mov (%eax),%eax */ \
asm (".byte 0x89 0x45 0xf8"); /* mov %eax,-0x8(%ebp) :va */ \
asm (".byte 0x50") /* push %eax */
#else // __MESC__
#define pop_va_arg asm (".byte 0x8b 0x45 0xfc 0xc1 0xe0 0x02 0x01 0xe8 0x83 0xc0 0x0c 0x8b 0x00 0x89 0x45 0xf8 0x50")
#endif
int
printf (char const* format, int va_args)
{
int va_arg = 0;
int va;
char *p = format;
while (*p)
if (*p != '%')
putchar (*p++);
else
{
p++;
char c = *p;
switch (c)
{
case '%': {putchar (*p); break;}
case 'c': {pop_va_arg; putchar ((char)va); va_arg++; break;}
case 'd': {pop_va_arg; puts (itoa (va)); va_arg++; break;}
case 's': {pop_va_arg; puts ((char*)va); va_arg++; break;}
default: putchar (*p);
}
p++;
}
return 0;
}