mes/lib/linux/arm-mes-gcc/crt1.c

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/* -*-comment-start: "//";comment-end:""-*-
* GNU Mes --- Maxwell Equations of Software
* Copyright © 2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
* Copyright © 2019,2020 Danny Milosavljevic <dannym@scratchpost.org>
*
* This file is part of GNU Mes.
*
* GNU 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.
*
* GNU 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 GNU Mes. If not, see <http://www.gnu.org/licenses/>.
*/
#include <mes/lib-mini.h>
//int main (int argc, char *argv[], char *envp[]);
#if !__TINYC__
/* Note: GCC automatically emits a preable in order to set up the
frame pointer: "push {fp}" "add fp, sp, 0"
*/
// *INDENT-OFF*
void
_start ()
{
asm (
"mov r0,#0\n\t"
"mov %0,r0\n"
: "=r" (__stdin)
: //no inputs ""
);
asm (
"mov r0,#1\n\t"
"mov %0,r0\n"
: "=r" (__stdout)
: //no inputs ""
);
asm (
"mov r0,#2\n\t"
"mov %0,r0\n"
: "=r" (__stderr)
: //no inputs ""
);
/* environ = argv + argc + 1 */
asm (
"ldr r0,[fp,#4]\n\t" /* r0 = argc */
"add r1,fp,#8\n\t" /* r1 = &argv[0] */
"add r2,r0,#1\n\t" /* r2 = r0 + 1 */
"lsl r2,#2\n\t" /* r2 = (r0 + 1) << 2 */
"add r2,r2,r1\n\t" /* r2 = ((r0 + 1) << 2) + r1 */
"push {r2}\n\t" /* envp */
"push {r1}\n\t" /* argv */
"push {r0}\n\t" /* argc */
"mov %0,r2\n\t"
: "=r" (environ)
: //no inputs ""
);
asm (
"ldr r0,[sp]\n\t" /* argc */
"ldr r1,[sp, #4]\n\t" /* argv */
"ldr r2,[sp, #8]\n\t" /* envp */
"bl main\n\t"
"mov r7, #1\n\t"
"swi #0\n\t"
"wfi \n\t"
);
}
#else //__TINYC__
__asm__ (".global _start\n");
__asm__ ("_start:\n");
__asm__ (".int 0xe52db004\n"); //push {fp} ; (str fp, [sp, #-4]!)
__asm__ (".int 0xe28db000\n"); //add fp, sp, #0
__asm__ (".int 0xe3a00000\n"); //mov r0, #0
__asm__ (".int 0xe1a02000\n"); //mov r2, r0
__asm__ (".int 0xe3003000\n"); //movw r3, #0
__asm__ (".int 0xe3403000\n"); //movt r3, #0
__asm__ (".int 0xe5832000\n"); //str r2, [r3]
__asm__ (".int 0xe3a00001\n"); //mov r0, #1
__asm__ (".int 0xe1a02000\n"); //mov r2, r0
__asm__ (".int 0xe3003000\n"); //movw r3, #0
__asm__ (".int 0xe3403000\n"); //movt r3, #0
__asm__ (".int 0xe5832000\n"); //str r2, [r3]
__asm__ (".int 0xe3a00002\n"); //mov r0, #2
__asm__ (".int 0xe1a02000\n"); //mov r2, r0
__asm__ (".int 0xe3003000\n"); //movw r3, #0
__asm__ (".int 0xe3403000\n"); //movt r3, #0
__asm__ (".int 0xe5832000\n"); //str r2, [r3]
__asm__ (".int 0xe59b0004\n"); //ldr r0, [fp, #4]
__asm__ (".int 0xe28b1008\n"); //add r1, fp, #8
__asm__ (".int 0xe2802001\n"); //add r2, r0, #1
__asm__ (".int 0xe1a02102\n"); //lsl r2, r2, #2
__asm__ (".int 0xe0822001\n"); //add r2, r2, r1
__asm__ (".int 0xe52d2004\n"); //push {r2} ; (str r2, [sp, #-4]!)
__asm__ (".int 0xe52d1004\n"); //push {r1} ; (str r1, [sp, #-4]!)
__asm__ (".int 0xe52d0004\n"); //push {r0} ; (str r0, [sp, #-4]!)
__asm__ (".int 0xe1a02002\n"); //mov r2, r2
__asm__ (".int 0xe3003000\n"); //movw r3, #0
__asm__ (".int 0xe3403000\n"); //movt r3, #0
__asm__ (".int 0xe5832000\n"); //str r2, [r3]
__asm__ (".int 0xe59d0000\n"); //ldr r0, [sp]
__asm__ (".int 0xe59d1004\n"); //ldr r1, [sp, #4]
__asm__ (".int 0xe59d2008\n"); //ldr r2, [sp, #8]
__asm__ (".int 0xebfffffe\n"); //bl 0 <main>
__asm__ (".int 0xe3a07001\n"); //mov r7, #1
__asm__ (".int 0xef000000\n"); //svc 0x00000000
__asm__ (".int 0xe320f003\n"); //wfi
__asm__ (".int 0xe320f000\n"); //nop {0}
__asm__ (".int 0xe28bd000\n"); //add sp, fp, #0
__asm__ (".int 0xe49db004\n"); //pop {fp} ; (ldr fp, [sp], #4)
__asm__ (".int 0xe12fff1e\n"); //bx lr
#endif //__TINYC__