RE: stack frame of gcc?

["Wang, Freeman (Xiaoguang)" <Freeman dot Wang at Marconi dot com>]

One of the functions has following disaseembly:

<xyz+2> inl $0x83, %eax
<xyz+4> inb (%dx), %al
<xyz+5> adcb %dl, 0x53(%esi)
<xyz+2> movl 0x8(%ebp), %esi		//load the first parameter to esi?

function xyz is defined as

int xyz(xyz_handle_t* xyzh, int flags)
{
	int retval;
	if(xyzh->field1 == 0){
		sub1(1,2,3);
		sub2(4,5,6);
	....
	}
}

Why no %ebp and %esp reservation here? 

Thanks
Freeman
	
-----Original Message-----
From: Wang, Freeman (Xiaoguang) 
Sent: Thursday, August 16, 2001 6:56 PM
To: 'gcc@gcc.gnu.org'
Subject: stack frame of gcc?


Hi,

What controls the stack frame of functions when compiled with gcc?

I found in some code that most of the functions follow the same convention:
pushl %ebp  
movl %esp,%ebp 
but there are still some functions have a strange header.

If the options are : -fno-defer-pop -funsigned-char -fdollars-in-identifiers
-nostdinc -fno-builtin -fvolatile -O2 -pipe -march=pentium, -DCPU=PENTIUM,
which kinds of functions will be assigned the conventional header? 

How many variations? 

Thanks
Freeman