91 lines
2.3 KiB
C
91 lines
2.3 KiB
C
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/* -*-comment-start: "//";comment-end:""-*-
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* GNU Mes --- Maxwell Equations of Software
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* Copyright © 2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
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* Copyright © 2019,2020 Danny Milosavljevic <dannym@scratchpost.org>
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* Copyright © 2021 W. J. van der Laan <laanwj@protonmail.com>
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*
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* This file is part of GNU Mes.
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*
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* GNU 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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* GNU 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 GNU Mes. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <mes/lib-mini.h>
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//int main (int argc, char *argv[], char *envp[]);
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/* gcc will generate the following preamble:
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addi sp,sp,-16
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sd s0,8(sp)
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addi s0,sp,16
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*/
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// *INDENT-OFF*
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void
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_start ()
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{
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asm (
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".option push\n\t"
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".option norelax\n\t"
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"lla gp, __global_pointer$\n\t"
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".option pop\n\t"
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"andi sp, sp, ~15\n\t" // make sure sp conforms to ABI alignment
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);
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asm (
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"li t0, 0\n\t"
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"mv %0, t0\n"
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: "=r" (__stdin)
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: //no inputs ""
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);
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asm (
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"li t0, 1\n\t"
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"mv %0, t0\n"
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: "=r" (__stdout)
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: //no inputs ""
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);
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asm (
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"li t0, 2\n\t"
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"mv %0, t0\n"
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: "=r" (__stderr)
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: //no inputs ""
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);
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// environ is &argv[argc + 1]
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asm (
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"lw t0, 0(s0)\n\t"
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"addi t1, s0, 8\n\t"
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"addi t0, t0, 1\n\t"
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"slli t0, t0, 3\n\t"
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"add %0, t1, t0\n\t"
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: "=r" (environ)
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: //no inputs ""
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);
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asm (
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"lw a0, 0(s0)\n\t" // a0 argc
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"addi a1, s0, 8\n\t" // a1 argv
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"mv a2, %0\n\t" // a2 envp
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"jal main\n\t"
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"li a7, 93\n\t" // SYS_exit
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"ecall\n\t" // exit(return value from main)
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"ebreak\n\t"
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: //no outputs ""
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: "r" (environ)
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);
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}
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