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+/* 64 bit S/390-specific implementation of profiling support.
+ Copyright (C) 2001-2017 Free Software Foundation, Inc.
+ Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com)
+ 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, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <sysdep.h>
+
+/* How profiling works on 64 bit S/390:
+ On the start of each function _mcount is called with the address of a
+ data word in %r1 (initialized to 0, used for counting). The compiler
+ with the option -p generates code of the form:
+
+ STM 6,15,24(15)
+ BRAS 13,.LTN0_0
+ .LT0_0:
+ .LC13: .long .LP0
+ .data
+ .align 4
+ .LP0: .long 0
+ .text
+ # function profiler
+ stg 14,4(15)
+ lg 1,.LC13-.LT0_0(13)
+ brasl 14,_mcount
+ lg 14,4(15)
+
+ The _mcount implementation now has to call __mcount_internal with the
+ address of .LP0 as first parameter and the return address as second
+ parameter. &.LP0 was loaded to %r1 and the return address is in %r14.
+ _mcount may not modify any register. */
+
+ .globl C_SYMBOL_NAME(_mcount)
+ .type C_SYMBOL_NAME(_mcount), @function
+ cfi_startproc
+ .align ALIGNARG(4)
+C_LABEL(_mcount)
+ /* Save the caller-clobbered registers. */
+ aghi %r15,-224
+ cfi_adjust_cfa_offset (224)
+ stmg %r14,%r5,160(%r15)
+ cfi_offset (r14, 0)
+ cfi_offset (r15, 8)
+ lg %r2,232(%r15) # callers address = first parameter
+ la %r2,0(%r2) # clear bit 0
+ la %r3,0(%r14) # callees address = second parameter
+
+#ifdef PIC
+ brasl %r14,__mcount_internal@PLT
+#else
+ brasl %r14,__mcount_internal
+#endif
+
+ /* Pop the saved registers. Please note that `mcount' has no
+ return value. */
+ lmg %r14,%r5,160(%r15)
+ aghi %r15,224
+ cfi_adjust_cfa_offset (-224)
+ br %r14
+ cfi_endproc
+ ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(_mcount))
+
+#undef mcount
+weak_alias (_mcount, mcount)