544 lines
9.0 KiB
C
544 lines
9.0 KiB
C
/* -*-comment-start: "//";comment-end:""-*-
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* Mes --- Maxwell Equations of Software
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* Copyright © 2016,2017 Jan Nieuwenhuizen <janneke@gnu.org>
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*
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* This file is part of Mes.
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*
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* Mes is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or (at
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* your option) any later version.
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*
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* Mes is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Mes. If not, see <http://www.gnu.org/licenses/>.
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*/
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char **g_environment = 0;
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int g_stdin = 0;
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#include <stdio.h>
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#include <mlibc.h>
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#if __GNUC__
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#include <stdlib.h>
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#endif
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#if __GNUC__ && !POSIX
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void
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exit (int code)
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{
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asm (
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"mov %0,%%ebx\n\t"
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"mov $1,%%eax\n\t"
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"int $0x80"
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: // no outputs "=" (r)
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: "" (code)
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);
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// not reached
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exit (0);
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}
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int
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read (int fd, void* buf, size_t n)
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{
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int r;
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//syscall (SYS_write, fd, s, n));
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asm (
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"mov %1,%%ebx\n\t"
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"mov %2,%%ecx\n\t"
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"mov %3,%%edx\n\t"
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"movl $0x3,%%eax\n\t"
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"int $0x80\n\t"
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"mov %%eax,%0\n\t"
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: "=r" (r)
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: "" (fd), "" (buf), "" (n)
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: "eax", "ebx", "ecx", "edx"
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);
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return r;
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}
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int
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write (int fd, char const* s, int n)
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{
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int r;
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//syscall (SYS_write, fd, s, n));
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asm (
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"mov %1,%%ebx\n\t"
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"mov %2,%%ecx\n\t"
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"mov %3,%%edx\n\t"
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"mov $0x4, %%eax\n\t"
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"int $0x80\n\t"
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"mov %%eax,%0\n\t"
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: "=r" (r)
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: "" (fd), "" (s), "" (n)
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: "eax", "ebx", "ecx", "edx"
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);
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return r;
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}
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int
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open (char const *s, int flags, ...)
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{
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int mode;
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asm (
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"mov %%ebp,%%eax\n\t"
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"add $0x10,%%eax\n\t"
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"mov (%%eax),%%eax\n\t"
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"mov %%eax,%0\n\t"
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: "=mode" (mode)
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: //no inputs ""
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);
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int r;
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//syscall (SYS_open, mode));
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asm (
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"mov %1,%%ebx\n\t"
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"mov %2,%%ecx\n\t"
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"mov %3,%%edx\n\t"
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"mov $0x5,%%eax\n\t"
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"int $0x80\n\t"
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"mov %%eax,%0\n\t"
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: "=r" (r)
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: "" (s), "" (flags), "" (mode)
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: "eax", "ebx", "ecx", "edx"
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);
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return r;
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}
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int
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access (char const *s, int mode)
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{
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int r;
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//syscall (SYS_access, mode));
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asm (
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"mov %1,%%ebx\n\t"
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"mov %2,%%ecx\n\t"
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"mov $0x21,%%eax\n\t"
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"int $0x80\n\t"
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"mov %%eax,%0\n\t"
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: "=r" (r)
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: "" (s), "" (mode)
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: "eax", "ebx", "ecx"
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);
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return r;
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}
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void *
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brk (void *p)
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{
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void *r;
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asm (
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"mov %1,%%ebx\n\t"
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"mov $0x2d,%%eax\n\t"
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"int $0x80\n\t"
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"mov %%eax,%0\n\t"
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: "=r" (r)
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: "" (p)
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: "eax", "ebx"
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);
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return r;
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}
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int
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fsync (int fd)
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{
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int r;
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//syscall (SYS_fsync, fd));
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asm (
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"mov %1,%%ebx\n\t"
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"mov $0x76, %%eax\n\t"
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"int $0x80\n\t"
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"mov %%eax,%0\n\t"
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: "=r" (r)
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: "" (fd)
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: "eax", "ebx"
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);
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return r;
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}
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int
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fputc (int c, int fd)
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{
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write (fd, (char*)&c, 1);
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return 0;
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}
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int
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putchar (int c)
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{
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write (STDOUT, (char*)&c, 1);
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return 0;
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}
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void *g_malloc_base = 0;
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void *
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malloc (size_t size)
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{
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void *p = brk (0);
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if (!g_malloc_base) g_malloc_base = p;
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brk (p+size);
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return p;
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}
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void *
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realloc (void *p, size_t size)
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{
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(void)p;
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brk (g_malloc_base + size);
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return g_malloc_base;
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}
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void
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free (void *p)
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{
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int *n = (int*)p-1;
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//munmap ((void*)p, *n);
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}
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size_t
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strlen (char const* s)
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{
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int i = 0;
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while (s[i]) i++;
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return i;
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}
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int
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strcmp (char const* a, char const* b)
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{
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while (*a && *b && *a == *b) {a++;b++;}
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return *a - *b;
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}
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char *
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strcpy (char *dest, char const *src)
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{
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char *p = dest;
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while (*src) *p++ = *src++;
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*p = 0;
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return dest;
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}
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int
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eputs (char const* s)
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{
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int i = strlen (s);
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write (STDERR, s, i);
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return 0;
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}
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int
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fputs (char const* s, int fd)
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{
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int i = strlen (s);
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write (fd, s, i);
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return 0;
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}
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int
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puts (char const* s)
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{
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int i = strlen (s);
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write (STDOUT, s, i);
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return 0;
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}
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void
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assert_fail (char* s)
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{
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eputs ("assert fail: ");
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eputs (s);
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eputs ("\n");
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*((int*)0) = 0;
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}
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#define assert(x) ((x) ? (void)0 : assert_fail (#x))
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int ungetc_char = -1;
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char ungetc_buf[2];
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int
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getchar ()
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{
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char c;
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int i;
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if (ungetc_char == -1)
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{
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int r = read (g_stdin, &c, 1);
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if (r < 1) return -1;
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i = c;
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}
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else
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i = ungetc_buf[ungetc_char--];
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if (i < 0) i += 256;
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return i;
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}
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int
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ungetc (int c, int fd)
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{
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assert (ungetc_char < 2);
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ungetc_buf[++ungetc_char] = c;
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return c;
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}
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char const* itoa (int);
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int
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strncmp (char const* a, char const* b, size_t length)
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{
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while (*a && *b && *a == *b && --length) {a++;b++;}
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return *a - *b;
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}
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char *
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getenv (char const* s)
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{
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char **p = g_environment;
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int length = strlen (s);
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while (*p)
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{
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if (!strncmp (s, *p, length) && *(*p + length) == '=') return (*p + length + 1);
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p++;
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}
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return 0;
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}
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int
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isdigit (int c)
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{
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return (c>='0') && (c<='9');
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}
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int
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atoi (char const *s)
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{
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int i = 0;
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int sign = 1;
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if (*s && *s == '-')
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{
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sign = -1;
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s++;
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}
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while (isdigit (*s))
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{
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i *= 10;
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i += (*s - '0');
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s++;
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}
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return i * sign;
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}
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int
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printf (char const* format, ...)
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{
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int va_arg = 0;
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int va;
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char const *p = format;
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while (*p)
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if (*p != '%')
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putchar (*p++);
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else
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{
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p++;
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char c = *p;
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switch (c)
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{
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case '%': {putchar (*p); break;}
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case 'c':
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{
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asm (
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"mov -0xc(%%ebp),%%eax\n\t"
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"shl $0x2,%%eax\n\t"
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"add %%ebp,%%eax\n\t"
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"add $0xc,%%eax\n\t"
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"mov (%%eax),%%eax\n\t"
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//"mov %%eax,%0\n\t"
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: "=va" (va)
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: //no inputs ""
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);
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putchar ((char)va);
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va_arg++;
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break;
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}
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case 'd': {
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asm (
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"mov -0xc(%%ebp),%%eax\n\t"
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"shl $0x2,%%eax\n\t"
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"add %%ebp,%%eax\n\t"
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"add $0xc,%%eax\n\t"
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"mov (%%eax),%%eax\n\t"
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//"mov %%eax,%0\n\t"
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: "=va" (va)
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: //no inputs ""
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);
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puts (itoa ((int)va));
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va_arg++;
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break;
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}
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case 's': {
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asm (
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"mov -0xc(%%ebp),%%eax\n\t"
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"shl $0x2,%%eax\n\t"
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"add %%ebp,%%eax\n\t"
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"add $0xc,%%eax\n\t"
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"mov (%%eax),%%eax\n\t"
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//"mov %%eax,%0\n\t"
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: "=va" (va)
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: //no inputs ""
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);
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puts ((char*)va);
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va_arg++;
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break;
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}
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default: putchar (*p);
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}
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p++;
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}
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return 0;
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}
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#endif
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char itoa_buf[10];
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char const*
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itoa (int x)
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{
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//static char itoa_buf[10];
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//char *p = buf+9;
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char *p = itoa_buf;
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p += 9;
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*p-- = 0;
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//int sign = x < 0;
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int sign;
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sign = x < 0;
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if (sign)
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x = -x;
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do
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{
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*p-- = '0' + (x % 10);
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x = x / 10;
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} while (x);
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if (sign)
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*p-- = '-';
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return p+1;
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}
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#if POSIX
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#define _GNU_SOURCE
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#include <assert.h>
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#include <fcntl.h>
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#include <string.h>
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#include <unistd.h>
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#endif // POSIX
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int
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fdputs (char const* s, int fd)
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{
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int i = strlen (s);
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write (fd, s, i);
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return 0;
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}
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#if POSIX
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int
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fdputc (int c, int fd)
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{
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write (fd, (char*)&c, 1);
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return 0;
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}
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int
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putchar (int c)
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{
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write (STDOUT, (char*)&c, 1);
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return 0;
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}
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int ungetc_char = -1;
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char ungetc_buf[2];
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int
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getchar ()
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{
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char c;
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int i;
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if (ungetc_char == -1)
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{
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int r = read (g_stdin, &c, 1);
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if (r < 1) return -1;
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i = c;
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}
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else
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i = ungetc_buf[ungetc_char--];
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if (i < 0) i += 256;
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return i;
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}
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int
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fdungetc (int c, int fd)
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{
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assert (ungetc_char < 2);
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ungetc_buf[++ungetc_char] = c;
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return c;
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}
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#endif // POSIX
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#if __GNUC__ && !POSIX
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void
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_start ()
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{
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// char **;
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asm (
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"mov %%ebp,%%eax\n\t"
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"addl $4,%%eax\n\t"
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"movzbl (%%eax),%%eax\n\t"
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"addl $3,%%eax\n\t"
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"shl $2,%%eax\n\t"
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"add %%ebp,%%eax\n\t"
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"movl %%eax,%0\n\t"
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: "=g_environment" (g_environment)
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: //no inputs ""
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);
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int r;
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asm (
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"mov %%ebp,%%eax\n\t"
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"addl $8,%%eax\n\t"
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"push %%eax\n\t"
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"mov %%ebp,%%eax\n\t"
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"addl $4,%%eax\n\t"
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"movzbl (%%eax),%%eax\n\t"
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"push %%eax\n\t"
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"call main\n\t"
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"movl %%eax,%0\n\t"
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: "=r" (r)
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: //no inputs ""
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);
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exit (r);
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}
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#endif // __GNUC__ && !POSIX
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