1 /* Machine-specific calling sequence for `mcount' profiling function. ia64
2 Copyright (C) 2000 Free Software Foundation, Inc.
3 Contributed by David Mosberger <davidm@hpl.hp.com>
4 This file is part of the GNU C Library.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
21 /* Assembly stub to invoke _mcount(). Compiler generated code calls
22 this stub before executing a function's prologue and without saving
23 any registers. It is therefore necessary to preserve the input
24 registers as they may contain function arguments. To work
25 correctly with frame-less functions, it is also necessary to
26 preserve the return pointer (b0 aka rp).
28 State upon entering _mcount:
30 r8 address of return value structure (used only when called
31 function returns a large structure)
32 r15 static link (used only for nested functions)
33 in0 ar.pfs to restore before returning to the function that
35 in1 gp value to restore before returning to the function that
37 in2 return address in the function that invoked the caller
39 in3 address of the global-offset table entry that holds the
40 profile count dword allocated by the compiler; to get
41 the address of this dword, use "ld8 in2=[in2]; this
42 dword can be used in any way by _mcount (including
43 not at all, as is the case with the current implementation)
44 b0 address to return to after _mcount is done
52 .prologue ASM_UNW_PRLG_RP|ASM_UNW_PRLG_PFS, ASM_UNW_PRLG_GRSAVE(4)
53 alloc loc1 = ar.pfs, 4, 4, 3, 0
56 mov loc2 = r8 // gcc uses r8 to pass pointer to return structure
58 mov loc3 = r15 // gcc uses r15 to pass the static link to nested functions
61 br.call.sptk.few rp = __mcount
71 adds r2 = _mcount_ret_helper - .here, r2
82 LOCAL_LEAF(_mcount_ret_helper)
87 alloc r2 = ar.pfs, 0, 0, 8, 0
90 END(_mcount_ret_helper)
92 weak_alias (_mcount, mcount)