• Basile B. (20/20) Feb 03 2018 compiles with -betterC -m32
• Adam D. Ruppe (8/10) Feb 03 2018 And that's the address of a D string, instead of the address of
• Basile B. (3/13) Feb 03 2018 Yeah, I forgot the ABI. It's working well
• Basile B. (21/42) Feb 03 2018 okay solved:
• Patrick Schluter (3/26) Feb 03 2018 [msg] contains the length of the string, so there's no need of

Basile B. <b2.temp gmx.com> writes:

compiles with -betterC -m32

module runnable;

__gshared static msg = "betterC";
__gshared static len = 7;

extern(C) int main(int argc, char** args)
{
     asm
     {
         naked;
         mov EDX, len ;//message length
         mov ECX, msg ;//message to write
         mov EBX, 1   ;//file descriptor (stdout)
         mov EAX, 4   ;//system call number (sys_write)
         int 0x80     ;//call kernel

         mov EBX, 0   ;//process' exit code
         mov EAX, 1   ;//system call number (sys_exit)
         int 0x80     ;//call kernel - this interrupt won't return
     }
}

nothing is printed. Could this work ?

Adam D. Ruppe <destructionator gmail.com> writes:

On Saturday, 3 February 2018 at 15:30:10 UTC, Basile B. wrote:
 __gshared static msg = "betterC";

That's a D string....

         mov ECX, msg ;//message to write

And that's the address of a D string, instead of the address of 
the characters.

You need to put the pointer in there. So either make msg a char*, 
or pass msg.ptr there. With inline asm the ptr word will cause 
weirdness so I tend to move the pointer and length into local 
variables first.

Basile B. <b2.temp gmx.com> writes:

On Saturday, 3 February 2018 at 15:38:02 UTC, Adam D. Ruppe wrote:
 On Saturday, 3 February 2018 at 15:30:10 UTC, Basile B. wrote:
 __gshared static msg = "betterC";

 That's a D string....

         mov ECX, msg ;//message to write

 And that's the address of a D string, instead of the address of 
 the characters.

 You need to put the pointer in there. So either make msg a 
 char*, or pass msg.ptr there. With inline asm the ptr word will 
 cause weirdness so I tend to move the pointer and length into 
 local variables first.

Yeah, I forgot the ABI. It's working well

https://forum.dlang.org/post/edjipahtfphiqmxsiioq forum.dlang.org

Basile B. <b2.temp gmx.com> writes:

On Saturday, 3 February 2018 at 15:30:10 UTC, Basile B. wrote:
 compiles with -betterC -m32

 module runnable;

 __gshared static msg = "betterC";
 __gshared static len = 7;

 extern(C) int main(int argc, char** args)
 {
     asm
     {
         naked;
         mov EDX, len ;//message length
         mov ECX, msg ;//message to write
         mov EBX, 1   ;//file descriptor (stdout)
         mov EAX, 4   ;//system call number (sys_write)
         int 0x80     ;//call kernel

         mov EBX, 0   ;//process' exit code
         mov EAX, 1   ;//system call number (sys_exit)
         int 0x80     ;//call kernel - this interrupt won't 
 return
     }
 }

 nothing is printed. Could this work ?

okay solved:



module runnable;

__gshared static msg = "betterC\n";
__gshared static len = 8;

extern(C) int main(int argc, char** args)
{
     asm
     {
         naked;
         mov EDX, len ;//message length
         mov ECX, [msg + 4] ;//message to write
         mov EBX, 1   ;//file descriptor (stdout)
         mov EAX, 4   ;//system call number (sys_write)
         int 0x80     ;//call kernel

         mov EBX, 0   ;//process' exit code
         mov EAX, 1   ;//system call number (sys_exit)
         int 0x80     ;//call kernel - this interrupt won't return
     }
}

the pointer to the string data is 4 bytes later...

Patrick Schluter <Patrick.Schluter bbox.fr> writes:

On Saturday, 3 February 2018 at 15:38:19 UTC, Basile B. wrote:
 On Saturday, 3 February 2018 at 15:30:10 UTC, Basile B. wrote:
 [...]

 okay solved:



 module runnable;

 __gshared static msg = "betterC\n";
 __gshared static len = 8;

 extern(C) int main(int argc, char** args)
 {
     asm
     {
         naked;
         mov EDX, len ;//message length
         mov ECX, [msg + 4] ;//message to write
         mov EBX, 1   ;//file descriptor (stdout)
         mov EAX, 4   ;//system call number (sys_write)
         int 0x80     ;//call kernel

         mov EBX, 0   ;//process' exit code
         mov EAX, 1   ;//system call number (sys_exit)
         int 0x80     ;//call kernel - this interrupt won't 
 return
     }
 }

 the pointer to the string data is 4 bytes later...

[msg] contains the length of the string, so there's no need of 
your len variable. Just saying.