glibc/sysdeps/powerpc/ppc-mcount.S

/* PowerPC-specific implementation of profiling support.
   Copyright (C) 1997, 1999 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

/* This would be bad.  */
#ifdef PROF
#undef PROF
#endif

#include <sysdep.h>

/* We do profiling as described in the SYSV ELF ABI, _mcount is called
   with the address of a data word in r0 (that is different for every
   routine, initialised to 0, and otherwise unused).  The caller has put
   the address the caller will return to in the usual place on the stack,
   4(r1).  _mcount is responsible for ensuring that when it returns no
   argument-passing registers are disturbed, and that the LR is set back
   to (what the caller sees as) 4(r1).

   This is intended so that the following code can be inserted at the
   front of any routine without changing the routine:

	.data
	.align	2
   0:	.long	0
	.previous
	mflr	r0
	lis	r11,0b@ha
	stw	r0,4(r1)
	addi	r0,r11,0b@l
	bl	_mcount
*/

ENTRY(_mcount)
	stwu	r1,-48(r1)
/* We need to save the parameter-passing registers.  */
	stw	r3, 12(r1)
	stw	r4, 16(r1)
	stw	r5, 20(r1)
	stw	r6, 24(r1)
	mflr	r4
	lwz	r3, 52(r1)
	mfcr	r5
	stw	r7, 28(r1)
	stw	r8, 32(r1)
	stw	r9, 36(r1)
	stw	r10,40(r1)
	stw	r4, 44(r1)
	stw	r5,  8(r1)
	bl	JUMPTARGET(__mcount_internal)
	nop
 /* Restore the registers...  */
	lwz     r6,  8(r1)
	lwz	r0, 44(r1)
	lwz	r3, 12(r1)
	mtctr	r0
	lwz	r4, 16(r1)
	mtcrf	0xff,r6
	lwz	r5, 20(r1)
	lwz	r6, 24(r1)
	lwz	r0, 52(r1)
	lwz	r7, 28(r1)
	lwz	r8, 32(r1)
	mtlr	r0
	lwz	r9, 36(r1)
	lwz	r10,40(r1)
 /* ...unwind the stack frame, and return to your usual programming.  */
	addi	r1,r1,48
	bctr
END(_mcount)