path: root/arch/x86/math-emu/reg_ld_str.c

/*---------------------------------------------------------------------------+
 |  reg_ld_str.c                                                             |
 |                                                                           |
 | All of the functions which transfer data between user memory and FPU_REGs.|
 |                                                                           |
 | Copyright (C) 1992,1993,1994,1996,1997                                    |
 |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
 |                  E-mail   billm@suburbia.net                              |
 |                                                                           |
 |                                                                           |
 +---------------------------------------------------------------------------*/

/*---------------------------------------------------------------------------+
 | Note:                                                                     |
 |    The file contains code which accesses user memory.                     |
 |    Emulator static data may change when user memory is accessed, due to   |
 |    other processes using the emulator while swapping is in progress.      |
 +---------------------------------------------------------------------------*/

#include "fpu_emu.h"

#include <asm/uaccess.h>

#include "fpu_system.h"
#include "exception.h"
#include "reg_constant.h"
#include "control_w.h"
#include "status_w.h"

#define DOUBLE_Emax 1023	/* largest valid exponent */
#define DOUBLE_Ebias 1023
#define DOUBLE_Emin (-1022)	/* smallest valid exponent */

#define SINGLE_Emax 127		/* largest valid exponent */
#define SINGLE_Ebias 127
#define SINGLE_Emin (-126)	/* smallest valid exponent */

static u_char normalize_no_excep(FPU_REG * r, int exp, int sign)
{
	u_char tag;

	setexponent16(r, exp);

	tag = FPU_normalize_nuo(r);
	stdexp(r);
	if (sign)
		setnegative(r);

	return tag;
}

int FPU_tagof(FPU_REG * ptr)
{
	int exp;

	exp = exponent16(ptr) & 0x7fff;
	if (exp == 0) {
		if (!(ptr->sigh | ptr->sigl)) {
			return TAG_Zero;
		}
		/* The number is a de-normal or pseudodenormal. */
		return TAG_Special;
	}

	if (exp == 0x7fff) {
		/* Is an Infinity, a NaN, or an unsupported data type. */
		return TAG_Special;
	}

	if (!(ptr->sigh & 0x80000000)) {
		/* Unsupported data type. */
		/* Valid numbers have the ms bit set to 1. */
		/* Unnormal. */
		return TAG_Special;
	}

	return TAG_Valid;
}

/* Get a long double from user memory */
int FPU_load_extended(long double __user * s, int stnr)
{
	FPU_REG *sti_ptr = &st(stnr);

	RE_ENTRANT_CHECK_OFF;
	FPU_access_ok(VERIFY_READ, s, 10);
	__copy_from_user(sti_ptr, s, 10);
	RE_ENTRANT_CHECK_ON;

	return FPU_tagof(sti_ptr);
}

/* Get a double from user memory */
int FPU_load_double(double __user * dfloat, FPU_REG * loaded_data)
{
	int exp, tag, negative;
	unsigned m64, l64;

	RE_ENTRANT_CHECK_OFF;
	FPU_access_ok(VERIFY_READ, dfloat, 8);
	FPU_get_user(m64, 1 + (unsigned long __user *)dfloat);
	FPU_get_user(l64, (unsigned long __user *)dfloat);
	RE_ENTRANT_CHECK_ON;

	negative = (m64 & 0x80000000) ? SIGN_Negative : SIGN_Positive;
	exp = ((m64 & 0x7ff00000) >> 20) - DOUBLE_Ebias + EXTENDED_Ebias;
	m64 &= 0xfffff;
	if (exp > DOUBLE_Emax + EXTENDED_Ebias) {
		/* Infinity or NaN */
		if ((