root/os/unix/rfork_thread.S

/*
 * Copyright (C) Igor Sysoev
 */


#include <sys/syscall.h>
#include <machine/asm.h>

/*
 * rfork_thread(3) - rfork_thread(flags, stack, func, arg);
 */

#define KERNCALL        int $0x80

ENTRY(rfork_thread)
        push    %ebp
        mov     %esp, %ebp
        push    %esi

        mov     12(%ebp), %esi  # the thread stack address

        sub     $4, %esi
        mov     20(%ebp), %eax  # the thread argument
        mov     %eax, (%esi)

        sub     $4, %esi
        mov     16(%ebp), %eax  # the thread start address
        mov     %eax, (%esi)

        push    8(%ebp)         # rfork(2) flags
        push    $0
        mov     $SYS_rfork, %eax
        KERNCALL
        jc      error

        cmp     $0, %edx
        jne     child

parent:
        add     $8, %esp
        pop     %esi
        leave
        ret

child:
        mov     %esi, %esp
        pop     %eax
        call    *%eax           # call a thread start address ...
        add     $4, %esp

        push    %eax
        push    $0
        mov     $SYS_exit, %eax # ... and exit(2) after a thread would return
        KERNCALL

error:
        add     $8, %esp
        pop     %esi
        leave
        PIC_PROLOGUE

        /* libc's cerror: jmp  PIC_PLT(HIDENAME(cerror)) */

        push    %eax
        call    PIC_PLT(CNAME(__error))
        pop     %ecx
        PIC_EPILOGUE
        mov     %ecx, (%eax)
        mov     $-1, %eax
        mov     $-1, %edx
        ret