uclibc-ng/libc/sysdeps/linux/sh/sysdep.h

/* Assembler macros for SH.
   Copyright (C) 1999, 2000, 2005 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.  */

#include <common/sysdep.h>

#include <features.h>
#include <libc-internal.h>

#ifdef	__ASSEMBLER__

/* Syntactic details of assembler.  */

#define ALIGNARG(log2) log2
/* For ELF we need the `.type' directive to make shared libs work right.  */
#define ASM_TYPE_DIRECTIVE(name,typearg) .type name,@##typearg;
#define ASM_SIZE_DIRECTIVE(name) .size name,.-name

#ifdef SHARED
#define PLTJMP(_x)	_x##@PLT
#else
#define PLTJMP(_x)	_x
#endif

/* Define an entry point visible from C.  */
#define	ENTRY(name)							      \
  ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(name);				      \
  ASM_TYPE_DIRECTIVE (C_SYMBOL_NAME(name),function)			      \
  .align ALIGNARG(5);							      \
  C_LABEL(name)								      \
  cfi_startproc;							      \
  CALL_MCOUNT

#undef	END
#define END(name)							      \
  cfi_endproc;								      \
  ASM_SIZE_DIRECTIVE(C_SYMBOL_NAME(name))

/* If compiled for profiling, call `mcount' at the start of each function.  */
#ifdef	PROF
#define CALL_MCOUNT					\
	mov.l	1f,r1;					\
	sts.l	pr,@-r15;				\
	cfi_adjust_cfa_offset (4);			\
	cfi_rel_offset (pr, 0);				\
	mova	2f,r0;					\
	jmp	@r1;					\
	 lds	r0,pr;					\
	.align	2;					\
1:	.long	mcount;					\
2:	lds.l	@r15+,pr;				\
	cfi_adjust_cfa_offset (-4);			\
	cfi_restore (pr)

#else
#define CALL_MCOUNT		/* Do nothing.  */
#endif

#ifdef	__UCLIBC_UNDERSCORES__
/* Since C identifiers are not normally prefixed with an underscore
   on this system, the asm identifier `syscall_error' intrudes on the
   C name space.  Make sure we use an innocuous name.  */
#define	syscall_error	__syscall_error
#define mcount		_mcount
#endif

/* For Linux we can use the system call table in the header file
	/usr/include/asm/unistd.h
   of the kernel.  But these symbols do not follow the SYS_* syntax
   so we have to redefine the `SYS_ify' macro here.  */
#undef SYS_ify
#define SYS_ify(syscall_name)	(__NR_##syscall_name)

#define ret	rts ; nop
/* The sh move insn is s, d.  */
#define MOVE(x,y)	mov x , y

/* Linux uses a negative return value to indicate syscall errors,
   unlike most Unices, which use the condition codes' carry flag.

   Since version 2.1 the return value of a system call might be
   negative even if the call succeeded.  E.g., the `lseek' system call
   might return a large offset.  Therefore we must not anymore test
   for < 0, but test for a real error by making sure the value in R0
   is a real error number.  Linus said he will make sure the no syscall
   returns a value in -1 .. -4095 as a valid result so we can savely
   test with -4095.  */

#define _IMM1 #-1
#define _IMM12 #-12
#undef	PSEUDO
#define	PSEUDO(name, syscall_name, args) \
 .text; \
 ENTRY (name); \
    DO_CALL (syscall_name, args); \
    mov r0,r1; \
    mov _IMM12,r2; \
    shad r2,r1; \
    not r1,r1; \
    tst r1,r1; \
    bf .Lpseudo_end; \
    SYSCALL_ERROR_HANDLER; \
 .Lpseudo_end:

#undef	PSEUDO_END
#define	PSEUDO_END(name) \
  END (name)

#undef	PSEUDO_NOERRNO
#define	PSEUDO_NOERRNO(name, syscall_name, args) \
 .text; \
 ENTRY (name); \
    DO_CALL (syscall_name, args)

#undef	PSEUDO_END_NOERRNO
#define	PSEUDO_END_NOERRNO(name) \
  END (name)

#define ret_NOERRNO ret

#define	PSEUDO_ERRVAL(name, syscall_name, args) \
 .text; \
 ENTRY (name); \
    DO_CALL (syscall_name, args);

#undef	PSEUDO_END_ERRVAL
#define	PSEUDO_END_ERRVAL(name) \
  END (name)

#define ret_ERRVAL ret

#ifndef __PIC__
# define SYSCALL_ERROR_HANDLER	\
	mov.l 0f,r1; \
	jmp @r1; \
	 mov r0,r4; \
	.align 2; \
     0: .long __syscall_error

#include <libc/sysdeps/linux/sh/syscall_error.S>
#else
# ifdef RTLD_PRIVATE_ERRNO

#  define SYSCALL_ERROR_HANDLER	\
	neg r0,r1; \
	mov.l 0f,r12; \
	mova 0f,r0; \
	add r0,r12; \
	mov.l 1f,r0; \
	mov.l r1,@(r0,r12)
	bra .Lpseudo_end; \
	 mov _IMM1,r0; \
	.align 2; \
     0: .long _GLOBAL_OFFSET_TABLE_; \
     1: .long rtld_errno@GOTOFF

# elif defined _LIBC_REENTRANT

#  if defined USE___THREAD

#   ifndef NOT_IN_libc
#    define SYSCALL_ERROR_ERRNO __libc_errno
#   else
#    define SYSCALL_ERROR_ERRNO errno
#   endif
#   define SYSCALL_ERROR_HANDLER \
	neg r0,r1; \
	mov r12,r2; \
	mov.l 0f,r12; \
	mova 0f,r0; \
	add r0,r12; \
	mov.l 1f,r0; \
	stc gbr, r4; \
	mov.l @(r0,r12),r0; \
	bra .Lskip; \
	add r4,r0; \
	.align 2; \
	1: .long SYSCALL_ERROR_ERRNO@GOTTPOFF; \
	.Lskip: \
	mov r2,r12; \
	mov.l r1,@r0; \
	bra .Lpseudo_end; \
	mov _IMM1,r0; \
	.align 2; \
	0: .long _GLOBAL_OFFSET_TABLE_
#  else

#   define SYSCALL_ERROR_HANDLER \
	neg r0,r1; \
	mov.l r14,@-r15; \
	mov.l r12,@-r15; \
	mov.l r1,@-r15; \
	mov.l 0f,r12; \
	mova 0f,r0; \
	add r0,r12; \
	sts.l pr,@-r15; \
	mov r15,r14; \
	mov.l 1f,r1; \
	bsrf r1; \
         nop; \
     2: mov r14,r15; \
	lds.l @r15+,pr; \
	mov.l @r15+,r1; \
	mov.l r1,@r0; \
	mov.l @r15+,r12; \
	mov.l @r15+,r14; \
	bra .Lpseudo_end; \
	 mov _IMM1,r0; \
	.align 2; \
     0: .long _GLOBAL_OFFSET_TABLE_; \
     1: .long PLTJMP(C_SYMBOL_NAME(__errno_location))-(2b-.)
/* A quick note: it is assumed that the call to `__errno_location' does
   not modify the stack!  */
#  endif
# else

/* Store (-r0) into errno through the GOT.  */
#  define SYSCALL_ERROR_HANDLER						      \
	neg r0,r1; \
	mov r12,r2; \
	mov.l 0f,r12; \
	mova 0f,r0; \
	add r0,r12; \
	mov.l 1f,r0; \
	mov.l @(r0,r12),r0; \
	mov r2,r12; \
	mov.l r1,@r0; \
	bra .Lpseudo_end; \
	 mov _IMM1,r0; \
	.align 2; \
     0: .long _GLOBAL_OFFSET_TABLE_; \
     1: .long errno@GOT
# endif	/* _LIBC_REENTRANT */
#endif	/* __PIC__ */

# ifdef __SH4__
#  define SYSCALL_INST_PAD \
	or r0,r0; or r0,r0; or r0,r0; or r0,r0; or r0,r0
# else
#  define SYSCALL_INST_PAD
# endif

#define SYSCALL_INST0	trapa #0x10
#define SYSCALL_INST1	trapa #0x11
#define SYSCALL_INST2	trapa #0x12
#define SYSCALL_INST3	trapa #0x13
#define SYSCALL_INST4	trapa #0x14
#define SYSCALL_INST5	mov.l @(0,r15),r0; trapa #0x15
#define SYSCALL_INST6	mov.l @(0,r15),r0; mov.l @(4,r15),r1; trapa #0x16

#undef	DO_CALL
#define DO_CALL(syscall_name, args)	\
    mov.l 1f,r3;			\
    SYSCALL_INST##args;			\
    SYSCALL_INST_PAD;			\
    bra 2f;				\
     nop;				\
    .align 2;				\
 1: .long SYS_ify (syscall_name);	\
 2:
#endif	/* __ASSEMBLER__ */

/* Pointer mangling support.  */
#if defined NOT_IN_libc && defined IS_IN_rtld
/* We cannot use the thread descriptor because in ld.so we use setjmp
   earlier than the descriptor is initialized.  Using a global variable
   is too complicated here since we have no PC-relative addressing mode.  */
#else
# ifdef __ASSEMBLER__
#  define PTR_MANGLE(reg, tmp) \
     stc gbr,tmp; mov.l @(POINTER_GUARD,tmp),tmp; xor tmp,reg
#  define PTR_MANGLE2(reg, tmp)	xor tmp,reg
#  define PTR_DEMANGLE(reg, tmp)	PTR_MANGLE (reg, tmp)
#  define PTR_DEMANGLE2(reg, tmp)	PTR_MANGLE2 (reg, tmp)
# else
#  define PTR_MANGLE(var) \
     (var) = (void *) ((uintptr_t) (var) ^ THREAD_GET_POINTER_GUARD ())
#  define PTR_DEMANGLE(var)	PTR_MANGLE (var)
# endif
#endif