Date: Thu, 18 Oct 2007 14:20:44 -0500 From: Derek Ragona <derek@computinginnovations.com> To: Yuri <yuri@rawbw.com> Cc: freebsd-questions@freebsd.org Subject: Re: Calling syscalls through int 0x80 documentation? Message-ID: <6.0.0.22.2.20071018141850.02482e78@mail.computinginnovations.com> In-Reply-To: <1192733243.4717aa3b1843f@webmail.rawbw.com> References: <1192731161.4717a21980065@webmail.rawbw.com> <6.0.0.22.2.20071018132410.02311ad8@mail.computinginnovations.com> <1192733243.4717aa3b1843f@webmail.rawbw.com>
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At 01:47 PM 10/18/2007, Yuri wrote: > > You can try here: > > http://www.ctyme.com/intr/int-80.htm > > >Thanks Derek. >This site just says: parameters on stack. > >So when following this I write the function 'mysyscall' (below) it doesn't >work. >It should return 3 but returns 14. >And I am on i386. > >So something is missing. > >Yuri > >--- code---- >#include <fcntl.h> > >extern int mysyscall ( > int syscall_no, > int a1, int a2, int a3, > int a4, int a5, int a6); > >asm( >".text\n" >"mysyscall:\n" >" push 28(%esp)\n" >" push 24(%esp)\n" >" push 20(%esp)\n" >" push 16(%esp)\n" >" push 12(%esp)\n" >" push 8(%esp)\n" >" push 4(%esp)\n" >" int $0x80\n" >" pop %ecx\n" >" pop %ecx\n" >" pop %ecx\n" >" pop %ecx\n" >" pop %ecx\n" >" pop %ecx\n" >" pop %ecx\n" >" ret\n" >".previous\n" >); > >main() { > char *fname = "myxxxfile"; > //int fd = open(fname, O_WRONLY|O_CREAT); > int fd = mysyscall(5/*open*/, (int)fname,O_WRONLY|O_CREAT,0,0,0,0); // open > printf("fd=%i\n",fd); >} I guess I'd ask why you want to use syscall at all to just open a file? I thought you wanted to access some hardware and had no other way to do that. -Derek -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. MailScanner thanks transtec Computers for their support.
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