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fpu_system.h

/*---------------------------------------------------------------------------+
 |  fpu_system.h                                                             |
 |                                                                           |
 | Copyright (C) 1992,1994,1997                                              |
 |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
 |                       Australia.  E-mail   billm@suburbia.net             |
 |                                                                           |
 +---------------------------------------------------------------------------*/

#ifndef _FPU_SYSTEM_H
#define _FPU_SYSTEM_H

/* system dependent definitions */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>

/* This sets the pointer FPU_info to point to the argument part
   of the stack frame of math_emulate() */
#define SETUP_DATA_AREA(arg)  FPU_info = (struct info *) &arg

/* s is always from a cpu register, and the cpu does bounds checking
 * during register load --> no further bounds checks needed */
#define LDT_DESCRIPTOR(s)     (((struct desc_struct *)current->mm->context.ldt)[(s) >> 3])
#define SEG_D_SIZE(x)         ((x).b & (3 << 21))
#define SEG_G_BIT(x)          ((x).b & (1 << 23))
#define SEG_GRANULARITY(x)    (((x).b & (1 << 23)) ? 4096 : 1)
#define SEG_286_MODE(x)       ((x).b & ( 0xff000000 | 0xf0000 | (1 << 23)))
#define SEG_BASE_ADDR(s)      (((s).b & 0xff000000) \
                         | (((s).b & 0xff) << 16) | ((s).a >> 16))
#define SEG_LIMIT(s)          (((s).b & 0xff0000) | ((s).a & 0xffff))
#define SEG_EXECUTE_ONLY(s)   (((s).b & ((1 << 11) | (1 << 9))) == (1 << 11))
#define SEG_WRITE_PERM(s)     (((s).b & ((1 << 11) | (1 << 9))) == (1 << 9))
#define SEG_EXPAND_DOWN(s)    (((s).b & ((1 << 11) | (1 << 10))) \
                         == (1 << 10))

#define I387                  (current->thread.i387)
#define FPU_info        (I387.soft.info)

#define FPU_CS                (*(unsigned short *) &(FPU_info->___cs))
#define FPU_SS                (*(unsigned short *) &(FPU_info->___ss))
#define FPU_DS                (*(unsigned short *) &(FPU_info->___ds))
#define FPU_EAX               (FPU_info->___eax)
#define FPU_EFLAGS            (FPU_info->___eflags)
#define FPU_EIP               (FPU_info->___eip)
#define FPU_ORIG_EIP          (FPU_info->___orig_eip)

#define FPU_lookahead           (I387.soft.lookahead)

/* nz if ip_offset and cs_selector are not to be set for the current
   instruction. */
#define no_ip_update          (*(u_char *)&(I387.soft.no_update))
#define FPU_rm                (*(u_char *)&(I387.soft.rm))

/* Number of bytes of data which can be legally accessed by the current
   instruction. This only needs to hold a number <= 108, so a byte will do. */
#define access_limit          (*(u_char *)&(I387.soft.alimit))

#define partial_status        (I387.soft.swd)
#define control_word          (I387.soft.cwd)
#define fpu_tag_word          (I387.soft.twd)
#define registers       (I387.soft.st_space)
#define top             (I387.soft.ftop)

#define instruction_address   (*(struct address *)&I387.soft.fip)
#define operand_address       (*(struct address *)&I387.soft.foo)

#define FPU_access_ok(x,y,z)  if ( !access_ok(x,y,z) ) \
                        math_abort(FPU_info,SIGSEGV)
#define FPU_abort       math_abort(FPU_info, SIGSEGV)

#undef FPU_IGNORE_CODE_SEGV
#ifdef FPU_IGNORE_CODE_SEGV
/* access_ok() is very expensive, and causes the emulator to run
   about 20% slower if applied to the code. Anyway, errors due to bad
   code addresses should be much rarer than errors due to bad data
   addresses. */
#define     FPU_code_access_ok(z)
#else
/* A simpler test than access_ok() can probably be done for
   FPU_code_access_ok() because the only possible error is to step
   past the upper boundary of a legal code area. */
#define     FPU_code_access_ok(z) FPU_access_ok(VERIFY_READ,(void __user *)FPU_EIP,z)
#endif

#define FPU_get_user(x,y)       get_user((x),(y))
#define FPU_put_user(x,y)       put_user((x),(y))

#endif

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