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	Since kernel 2.6.0 all Linux version accept the system call number
in register 1 for svc 0. There is no need to have special handling
that uses EX for system calls < 256. This will simplify and speed
up that code.
A microbenchmark doing "syscall(__NR_getpid);" in a loops gets faster
by ~12%.
        * sysdeps/unix/sysv/linux/s390/s390-32/syscall.S: Simplify
        code by always using SVC 0 instead of EX.
        * sysdeps/unix/sysv/linux/s390/s390-64/syscall.S: Likewise.
		
	
		
			
				
	
	
		
			63 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
			
		
		
	
	
			63 lines
		
	
	
		
			2.1 KiB
		
	
	
	
		
			ArmAsm
		
	
	
	
	
	
/* Copyright (C) 2001-2017 Free Software Foundation, Inc.
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   Contributed by Martin Schwidefsky (schwidefsky@de.ibm.com).
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   This file is part of the GNU C Library.
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   The GNU C Library is free software; you can redistribute it and/or
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   modify it under the terms of the GNU Lesser General Public
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   License as published by the Free Software Foundation; either
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   version 2.1 of the License, or (at your option) any later version.
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   The GNU C Library is distributed in the hope that it will be useful,
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   but WITHOUT ANY WARRANTY; without even the implied warranty of
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   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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   Lesser General Public License for more details.
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   You should have received a copy of the GNU Lesser General Public
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   License along with the GNU C Library; if not, see
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   <http://www.gnu.org/licenses/>.  */
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#include <sysdep.h>
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/* Please consult the file sysdeps/unix/sysv/linux/s390/sysdep.h for
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   more information about the value -4095 used below.*/
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ENTRY (syscall)
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	/* Save registers and setup stack.  */
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	stmg	%r6,%r15,48(%r15)  /* Save registers.  */
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	cfi_offset (%r15,-40)
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	cfi_offset (%r14,-48)
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	cfi_offset (%r13,-56)
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	cfi_offset (%r12,-64)
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	cfi_offset (%r11,-72)
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	cfi_offset (%r10,-80)
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	cfi_offset (%r9,-88)
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	cfi_offset (%r8,-96)
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	cfi_offset (%r7,-104)
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	cfi_offset (%r6,-112)
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	lgr	%r1,%r15
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	lg	%r0,8(%r15)	   /* Load eos.	 */
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	aghi	%r15,-160	   /* Buy stack space.	*/
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	cfi_adjust_cfa_offset (160)
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	stg	%r1,0(%r15)	   /* Store back chain.	 */
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	stg	%r0,8(%r15)	   /* Store eos.  */
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	lgr    %r1,%r2		   /* Move syscall number.  */
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	lgr    %r2,%r3		   /* First parameter.	*/
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	lgr    %r3,%r4		   /* Second parameter.	 */
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	lgr    %r4,%r5		   /* Third parameter.	*/
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	lgr    %r5,%r6		   /* Fourth parameter.	 */
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	lg     %r6,320(%r15)	   /* Fifth parameter.	*/
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	lg     %r7,328(%r15)	   /* Sixth parameter.	*/
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	svc    0
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	lg     %r15,0(%r15)        /* Load back chain.  */
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	cfi_adjust_cfa_offset (-160)
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	lmg    %r6,%r15,48(%r15)   /* Load registers.  */
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	lghi   %r0,-4095
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	clgr   %r2,%r0		   /* Check R2 for error.  */
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	jgnl   SYSCALL_ERROR_LABEL
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	br     %r14		   /* Return to caller.	 */
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PSEUDO_END (syscall)
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