usr/src/lib/csu/mips/crt0.s

/*
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Ralph Campbell.
 *
 * %sccs.include.redist.c%
 *
 *      @(#)crt0.s      5.7 (Berkeley) %G%
 */

#include <machine/regdef.h>
#include <machine/machAsmDefs.h>

        .comm   environ, 4
        .data
        .align  2
        .globl  __progname
__progname:
        .word   $L1
$L1:
        .word   0               # null string plus padding
        .text

NON_LEAF(start, 24, ra)
        .set    noreorder
        lw      s0, 0(sp)       # get argc from stack
        addu    s1, sp, 4       # get pointer to argv
        addu    s2, s1, 4       # skip null pointer on stack
        sll     v0, s0, 2       # add number of argv pointers
        addu    s2, s2, v0      # final pointer to environment list
        sw      s2, environ     # save environment pointer
        subu    sp, sp, 24      # allocate standard frame
        .mask   0x80000000, -4
        sw      zero, 20(sp)    # clear return address for debugging
#ifdef MCRT0
eprol:
        la      a0, eprol
        la      a1, etext
        jal     monstartup      # monstartup(eprol, etext);
        nop
        la      a0, _mcleanup
        jal     atexit          # atext(_mcleanup);
        nop
        sw      zero, errno
#endif
        lw      a0, 0(s1)       # a0 = argv[0];
        nop
        beq     a0, zero, 2f    # skip if a0 == NULL
        move    s3, a0          # save argv[0]
        jal     strrchr
        li      a1, 0x2f        # a1 = '/'
        bne     v0, zero, 1f    # if slash found
        addu    v0, v0, 1
        move    v0, s3          # v0 = argv[0];
1:
        sw      v0, __progname
2:
        move    a0, s0
        move    a1, s1
        jal     main            # v0 = main(argc, argv, env);
        move    a2, s2
        jal     exit            # exit(v0);
        move    a0, v0
        break   0
        .set    reorder
END(start)

LEAF(__main)
        j       ra
END(__main)

#ifndef MCRT0
LEAF(moncontrol)
        j       ra
END(moncontrol)

LEAF(_mcount)
        .set    noreorder
        .set    noat
        addu    sp, sp, 8       # undo push
        j       ra
        move    ra, AT
        .set    at
        .set    reorder
END(_mcount)
#endif