arch/x86/math-emu/errors.c - arm/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*---------------------------------------------------------------------------+
  |  errors.c                                                                 |
  |                                                                           |
  |  The error handling functions for wm-FPU-emu                              |
  |                                                                           |
  | Copyright (C) 1992,1993,1994,1996                                         |
  |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
  |                  E-mail   billm@jacobi.maths.monash.edu.au                |
  |                                                                           |
  |                                                                           |
  +---------------------------------------------------------------------------*/

 /*---------------------------------------------------------------------------+
  | 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 <linux/signal.h>

 #include <linux/uaccess.h>

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

 /* */
 #undef PRINT_MESSAGES
 /* */

 #if 0
 void Un_impl(void)
 {
 	u_char byte1, FPU_modrm;
 	unsigned long address = FPU_ORIG_EIP;

 	RE_ENTRANT_CHECK_OFF;
 	/* No need to check access_ok(), we have previously fetched these bytes. */
 	printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *)address);
 	if (FPU_CS == __USER_CS) {
 		while (1) {
 			FPU_get_user(byte1, (u_char __user *) address);
 			if ((byte1 & 0xf8) == 0xd8)
 				break;
 			printk("[%02x]", byte1);
 			address++;
 		}
 		printk("%02x ", byte1);
 		FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);

 		if (FPU_modrm >= 0300)
 			printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8,
 			       FPU_modrm & 7);
 		else
 			printk("/%d\n", (FPU_modrm >> 3) & 7);
 	} else {
 		printk("cs selector = %04x\n", FPU_CS);
 	}

 	RE_ENTRANT_CHECK_ON;

 	EXCEPTION(EX_Invalid);

 }
 #endif /*  0  */

 /*
    Called for opcodes which are illegal and which are known to result in a
    SIGILL with a real 80486.
    */
 void FPU_illegal(void)
 {
 	math_abort(FPU_info, SIGILL);
 }

 void FPU_printall(void)
 {
 	int i;
 	static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty",
 		"DeNorm", "Inf", "NaN"
 	};
 	u_char byte1, FPU_modrm;
 	unsigned long address = FPU_ORIG_EIP;

 	RE_ENTRANT_CHECK_OFF;
 	/* No need to check access_ok(), we have previously fetched these bytes. */
 	printk("At %p:", (void *)address);
 	if (FPU_CS == __USER_CS) {
 #define MAX_PRINTED_BYTES 20
 		for (i = 0; i < MAX_PRINTED_BYTES; i++) {
 			FPU_get_user(byte1, (u_char __user *) address);
 			if ((byte1 & 0xf8) == 0xd8) {
 				printk(" %02x", byte1);
 				break;
 			}
 			printk(" [%02x]", byte1);
 			address++;
 		}
 		if (i == MAX_PRINTED_BYTES)
 			printk(" [more..]\n");
 		else {
 			FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);

 			if (FPU_modrm >= 0300)
 				printk(" %02x (%02x+%d)\n", FPU_modrm,
 				       FPU_modrm & 0xf8, FPU_modrm & 7);
 			else
 				printk(" /%d, mod=%d rm=%d\n",
 				       (FPU_modrm >> 3) & 7,
 				       (FPU_modrm >> 6) & 3, FPU_modrm & 7);
 		}
 	} else {
 		printk("%04x\n", FPU_CS);
 	}

 	partial_status = status_word();

 #ifdef DEBUGGING
 	if (partial_status & SW_Backward)
 		printk("SW: backward compatibility\n");
 	if (partial_status & SW_C3)
 		printk("SW: condition bit 3\n");
 	if (partial_status & SW_C2)
 		printk("SW: condition bit 2\n");
 	if (partial_status & SW_C1)
 		printk("SW: condition bit 1\n");
 	if (partial_status & SW_C0)
 		printk("SW: condition bit 0\n");
 	if (partial_status & SW_Summary)
 		printk("SW: exception summary\n");
 	if (partial_status & SW_Stack_Fault)
 		printk("SW: stack fault\n");
 	if (partial_status & SW_Precision)
 		printk("SW: loss of precision\n");
 	if (partial_status & SW_Underflow)
 		printk("SW: underflow\n");
 	if (partial_status & SW_Overflow)
 		printk("SW: overflow\n");
 	if (partial_status & SW_Zero_Div)
 		printk("SW: divide by zero\n");
 	if (partial_status & SW_Denorm_Op)
 		printk("SW: denormalized operand\n");
 	if (partial_status & SW_Invalid)
 		printk("SW: invalid operation\n");
 #endif /* DEBUGGING */

 	printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n", partial_status & 0x8000 ? 1 : 0,	/* busy */
 	       (partial_status & 0x3800) >> 11,	/* stack top pointer */
 	       partial_status & 0x80 ? 1 : 0,	/* Error summary status */
 	       partial_status & 0x40 ? 1 : 0,	/* Stack flag */
 	       partial_status & SW_C3 ? 1 : 0, partial_status & SW_C2 ? 1 : 0,	/* cc */
 	       partial_status & SW_C1 ? 1 : 0, partial_status & SW_C0 ? 1 : 0,	/* cc */
 	       partial_status & SW_Precision ? 1 : 0,
 	       partial_status & SW_Underflow ? 1 : 0,
 	       partial_status & SW_Overflow ? 1 : 0,
 	       partial_status & SW_Zero_Div ? 1 : 0,
 	       partial_status & SW_Denorm_Op ? 1 : 0,
 	       partial_status & SW_Invalid ? 1 : 0);

 	printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d     ef=%d%d%d%d%d%d\n",
 	       control_word & 0x1000 ? 1 : 0,
 	       (control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
 	       (control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
 	       control_word & 0x80 ? 1 : 0,
 	       control_word & SW_Precision ? 1 : 0,
 	       control_word & SW_Underflow ? 1 : 0,
 	       control_word & SW_Overflow ? 1 : 0,
 	       control_word & SW_Zero_Div ? 1 : 0,
 	       control_word & SW_Denorm_Op ? 1 : 0,
 	       control_word & SW_Invalid ? 1 : 0);

 	for (i = 0; i < 8; i++) {
 		FPU_REG *r = &st(i);
 		u_char tagi = FPU_gettagi(i);
 		switch (tagi) {
 		case TAG_Empty:
 			continue;
 			break;
 		case TAG_Zero:
 		case TAG_Special:
 			tagi = FPU_Special(r);
 		case TAG_Valid:
 			printk("st(%d)  %c .%04lx %04lx %04lx %04lx e%+-6d ", i,
 			       getsign(r) ? '-' : '+',
 			       (long)(r->sigh >> 16),
 			       (long)(r->sigh & 0xFFFF),
 			       (long)(r->sigl >> 16),
 			       (long)(r->sigl & 0xFFFF),
 			       exponent(r) - EXP_BIAS + 1);
 			break;
 		default:
 			printk("Whoops! Error in errors.c: tag%d is %d ", i,
 			       tagi);
 			continue;
 			break;
 		}
 		printk("%s\n", tag_desc[(int)(unsigned)tagi]);
 	}

 	RE_ENTRANT_CHECK_ON;

 }

 static struct {
 	int type;
 	const char *name;
 } exception_names[] = {
 	{
 	EX_StackOver, "stack overflow"}, {
 	EX_StackUnder, "stack underflow"}, {
 	EX_Precision, "loss of precision"}, {
 	EX_Underflow, "underflow"}, {
 	EX_Overflow, "overflow"}, {
 	EX_ZeroDiv, "divide by zero"}, {
 	EX_Denormal, "denormalized operand"}, {
 	EX_Invalid, "invalid operation"}, {
 	EX_INTERNAL, "INTERNAL BUG in " FPU_VERSION}, {
 	0, NULL}
 };

 /*
  EX_INTERNAL is always given with a code which indicates where the
  error was detected.

  Internal error types:
        0x14   in fpu_etc.c
        0x1nn  in a *.c file:
               0x101  in reg_add_sub.c
               0x102  in reg_mul.c
               0x104  in poly_atan.c
               0x105  in reg_mul.c
               0x107  in fpu_trig.c
 	      0x108  in reg_compare.c
 	      0x109  in reg_compare.c
 	      0x110  in reg_add_sub.c
 	      0x111  in fpe_entry.c
 	      0x112  in fpu_trig.c
 	      0x113  in errors.c
 	      0x115  in fpu_trig.c
 	      0x116  in fpu_trig.c
 	      0x117  in fpu_trig.c
 	      0x118  in fpu_trig.c
 	      0x119  in fpu_trig.c
 	      0x120  in poly_atan.c
 	      0x121  in reg_compare.c
 	      0x122  in reg_compare.c
 	      0x123  in reg_compare.c
 	      0x125  in fpu_trig.c
 	      0x126  in fpu_entry.c
 	      0x127  in poly_2xm1.c
 	      0x128  in fpu_entry.c
 	      0x129  in fpu_entry.c
 	      0x130  in get_address.c
 	      0x131  in get_address.c
 	      0x132  in get_address.c
 	      0x133  in get_address.c
 	      0x140  in load_store.c
 	      0x141  in load_store.c
               0x150  in poly_sin.c
               0x151  in poly_sin.c
 	      0x160  in reg_ld_str.c
 	      0x161  in reg_ld_str.c
 	      0x162  in reg_ld_str.c
 	      0x163  in reg_ld_str.c
 	      0x164  in reg_ld_str.c
 	      0x170  in fpu_tags.c
 	      0x171  in fpu_tags.c
 	      0x172  in fpu_tags.c
 	      0x180  in reg_convert.c
        0x2nn  in an *.S file:
               0x201  in reg_u_add.S
               0x202  in reg_u_div.S
               0x203  in reg_u_div.S
               0x204  in reg_u_div.S
               0x205  in reg_u_mul.S
               0x206  in reg_u_sub.S
               0x207  in wm_sqrt.S
 	      0x208  in reg_div.S
               0x209  in reg_u_sub.S
               0x210  in reg_u_sub.S
               0x211  in reg_u_sub.S
               0x212  in reg_u_sub.S
 	      0x213  in wm_sqrt.S
 	      0x214  in wm_sqrt.S
 	      0x215  in wm_sqrt.S
 	      0x220  in reg_norm.S
 	      0x221  in reg_norm.S
 	      0x230  in reg_round.S
 	      0x231  in reg_round.S
 	      0x232  in reg_round.S
 	      0x233  in reg_round.S
 	      0x234  in reg_round.S
 	      0x235  in reg_round.S
 	      0x236  in reg_round.S
 	      0x240  in div_Xsig.S
 	      0x241  in div_Xsig.S
 	      0x242  in div_Xsig.S
  */

 asmlinkage __visible void FPU_exception(int n)
 {
 	int i, int_type;

 	int_type = 0;		/* Needed only to stop compiler warnings */
 	if (n & EX_INTERNAL) {
 		int_type = n - EX_INTERNAL;
 		n = EX_INTERNAL;
 		/* Set lots of exception bits! */
 		partial_status |= (SW_Exc_Mask | SW_Summary | SW_Backward);
 	} else {
 		/* Extract only the bits which we use to set the status word */
 		n &= (SW_Exc_Mask);
 		/* Set the corresponding exception bit */
 		partial_status |= n;
 		/* Set summary bits iff exception isn't masked */
 		if (partial_status & ~control_word & CW_Exceptions)
 			partial_status |= (SW_Summary | SW_Backward);
 		if (n & (SW_Stack_Fault | EX_Precision)) {
 			if (!(n & SW_C1))
 				/* This bit distinguishes over- from underflow for a stack fault,
 				   and roundup from round-down for precision loss. */
 				partial_status &= ~SW_C1;
 		}
 	}

 	RE_ENTRANT_CHECK_OFF;
 	if ((~control_word & n & CW_Exceptions) || (n == EX_INTERNAL)) {
 		/* Get a name string for error reporting */
 		for (i = 0; exception_names[i].type; i++)
 			if ((exception_names[i].type & n) ==
 			    exception_names[i].type)
 				break;

 		if (exception_names[i].type) {
 #ifdef PRINT_MESSAGES
 			printk("FP Exception: %s!\n", exception_names[i].name);
 #endif /* PRINT_MESSAGES */
 		} else
 			printk("FPU emulator: Unknown Exception: 0x%04x!\n", n);

 		if (n == EX_INTERNAL) {
 			printk("FPU emulator: Internal error type 0x%04x\n",
 			       int_type);
 			FPU_printall();
 		}
 #ifdef PRINT_MESSAGES
 		else
 			FPU_printall();
 #endif /* PRINT_MESSAGES */

 		/*
 		 * The 80486 generates an interrupt on the next non-control FPU
 		 * instruction. So we need some means of flagging it.
 		 * We use the ES (Error Summary) bit for this.
 		 */
 	}
 	RE_ENTRANT_CHECK_ON;

 #ifdef __DEBUG__
 	math_abort(FPU_info, SIGFPE);
 #endif /* __DEBUG__ */

 }

 /* Real operation attempted on a NaN. */
 /* Returns < 0 if the exception is unmasked */
 int real_1op_NaN(FPU_REG *a)
 {
 	int signalling, isNaN;

 	isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000);

 	/* The default result for the case of two "equal" NaNs (signs may
 	   differ) is chosen to reproduce 80486 behaviour */
 	signalling = isNaN && !(a->sigh & 0x40000000);

 	if (!signalling) {
 		if (!isNaN) {	/* pseudo-NaN, or other unsupported? */
 			if (control_word & CW_Invalid) {
 				/* Masked response */
 				reg_copy(&CONST_QNaN, a);
 			}
 			EXCEPTION(EX_Invalid);
 			return (!(control_word & CW_Invalid) ? FPU_Exception :
 				0) | TAG_Special;
 		}
 		return TAG_Special;
 	}

 	if (control_word & CW_Invalid) {
 		/* The masked response */
 		if (!(a->sigh & 0x80000000)) {	/* pseudo-NaN ? */
 			reg_copy(&CONST_QNaN, a);
 		}
 		/* ensure a Quiet NaN */
 		a->sigh |= 0x40000000;
 	}

 	EXCEPTION(EX_Invalid);

 	return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
 }

 /* Real operation attempted on two operands, one a NaN. */
 /* Returns < 0 if the exception is unmasked */
 int real_2op_NaN(FPU_REG const *b, u_char tagb,
 		 int deststnr, FPU_REG const *defaultNaN)
 {
 	FPU_REG *dest = &st(deststnr);
 	FPU_REG const *a = dest;
 	u_char taga = FPU_gettagi(deststnr);
 	FPU_REG const *x;
 	int signalling, unsupported;

 	if (taga == TAG_Special)
 		taga = FPU_Special(a);
 	if (tagb == TAG_Special)
 		tagb = FPU_Special(b);

 	/* TW_NaN is also used for unsupported data types. */
 	unsupported = ((taga == TW_NaN)
 		       && !((exponent(a) == EXP_OVER)
 			    && (a->sigh & 0x80000000)))
 	    || ((tagb == TW_NaN)
 		&& !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)));
 	if (unsupported) {
 		if (control_word & CW_Invalid) {
 			/* Masked response */
 			FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
 		}
 		EXCEPTION(EX_Invalid);
 		return (!(control_word & CW_Invalid) ? FPU_Exception : 0) |
 		    TAG_Special;
 	}

 	if (taga == TW_NaN) {
 		x = a;
 		if (tagb == TW_NaN) {
 			signalling = !(a->sigh & b->sigh & 0x40000000);
 			if (significand(b) > significand(a))
 				x = b;
 			else if (significand(b) == significand(a)) {
 				/* The default result for the case of two "equal" NaNs (signs may
 				   differ) is chosen to reproduce 80486 behaviour */
 				x = defaultNaN;
 			}
 		} else {
 			/* return the quiet version of the NaN in a */
 			signalling = !(a->sigh & 0x40000000);
 		}
 	} else
 #ifdef PARANOID
 	if (tagb == TW_NaN)
 #endif /* PARANOID */
 	{
 		signalling = !(b->sigh & 0x40000000);
 		x = b;
 	}
 #ifdef PARANOID
 	else {
 		signalling = 0;
 		EXCEPTION(EX_INTERNAL | 0x113);
 		x = &CONST_QNaN;
 	}
 #endif /* PARANOID */

 	if ((!signalling) || (control_word & CW_Invalid)) {
 		if (!x)
 			x = b;

 		if (!(x->sigh & 0x80000000))	/* pseudo-NaN ? */
 			x = &CONST_QNaN;

 		FPU_copy_to_regi(x, TAG_Special, deststnr);

 		if (!signalling)
 			return TAG_Special;

 		/* ensure a Quiet NaN */
 		dest->sigh |= 0x40000000;
 	}

 	EXCEPTION(EX_Invalid);

 	return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
 }

 /* Invalid arith operation on Valid registers */
 /* Returns < 0 if the exception is unmasked */
 asmlinkage __visible int arith_invalid(int deststnr)
 {

 	EXCEPTION(EX_Invalid);

 	if (control_word & CW_Invalid) {
 		/* The masked response */
 		FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
 	}

 	return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Valid;

 }

 /* Divide a finite number by zero */
 asmlinkage __visible int FPU_divide_by_zero(int deststnr, u_char sign)
 {
 	FPU_REG *dest = &st(deststnr);
 	int tag = TAG_Valid;

 	if (control_word & CW_ZeroDiv) {
 		/* The masked response */
 		FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr);
 		setsign(dest, sign);
 		tag = TAG_Special;
 	}

 	EXCEPTION(EX_ZeroDiv);

 	return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) | tag;

 }

 /* This may be called often, so keep it lean */
 int set_precision_flag(int flags)
 {
 	if (control_word & CW_Precision) {
 		partial_status &= ~(SW_C1 & flags);
 		partial_status |= flags;	/* The masked response */
 		return 0;
 	} else {
 		EXCEPTION(flags);
 		return 1;
 	}
 }

 /* This may be called often, so keep it lean */
 asmlinkage __visible void set_precision_flag_up(void)
 {
 	if (control_word & CW_Precision)
 		partial_status |= (SW_Precision | SW_C1);	/* The masked response */
 	else
 		EXCEPTION(EX_Precision | SW_C1);
 }

 /* This may be called often, so keep it lean */
 asmlinkage __visible void set_precision_flag_down(void)
 {
 	if (control_word & CW_Precision) {	/* The masked response */
 		partial_status &= ~SW_C1;
 		partial_status |= SW_Precision;
 	} else
 		EXCEPTION(EX_Precision);
 }

 asmlinkage __visible int denormal_operand(void)
 {
 	if (control_word & CW_Denormal) {	/* The masked response */
 		partial_status |= SW_Denorm_Op;
 		return TAG_Special;
 	} else {
 		EXCEPTION(EX_Denormal);
 		return TAG_Special | FPU_Exception;
 	}
 }

 asmlinkage __visible int arith_overflow(FPU_REG *dest)
 {
 	int tag = TAG_Valid;

 	if (control_word & CW_Overflow) {
 		/* The masked response */
 /* ###### The response here depends upon the rounding mode */
 		reg_copy(&CONST_INF, dest);
 		tag = TAG_Special;
 	} else {
 		/* Subtract the magic number from the exponent */
 		addexponent(dest, (-3 * (1 << 13)));
 	}

 	EXCEPTION(EX_Overflow);
 	if (control_word & CW_Overflow) {
 		/* The overflow exception is masked. */
 		/* By definition, precision is lost.
 		   The roundup bit (C1) is also set because we have
 		   "rounded" upwards to Infinity. */
 		EXCEPTION(EX_Precision | SW_C1);
 		return tag;
 	}

 	return tag;

 }

 asmlinkage __visible int arith_underflow(FPU_REG *dest)
 {
 	int tag = TAG_Valid;

 	if (control_word & CW_Underflow) {
 		/* The masked response */
 		if (exponent16(dest) <= EXP_UNDER - 63) {
 			reg_copy(&CONST_Z, dest);
 			partial_status &= ~SW_C1;	/* Round down. */
 			tag = TAG_Zero;
 		} else {
 			stdexp(dest);
 		}
 	} else {
 		/* Add the magic number to the exponent. */
 		addexponent(dest, (3 * (1 << 13)) + EXTENDED_Ebias);
 	}

 	EXCEPTION(EX_Underflow);
 	if (control_word & CW_Underflow) {
 		/* The underflow exception is masked. */
 		EXCEPTION(EX_Precision);
 		return tag;
 	}

 	return tag;

 }

 void FPU_stack_overflow(void)
 {

 	if (control_word & CW_Invalid) {
 		/* The masked response */
 		top--;
 		FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
 	}

 	EXCEPTION(EX_StackOver);

 	return;

 }

 void FPU_stack_underflow(void)
 {

 	if (control_word & CW_Invalid) {
 		/* The masked response */
 		FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
 	}

 	EXCEPTION(EX_StackUnder);

 	return;

 }

 void FPU_stack_underflow_i(int i)
 {

 	if (control_word & CW_Invalid) {
 		/* The masked response */
 		FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
 	}

 	EXCEPTION(EX_StackUnder);

 	return;

 }

 void FPU_stack_underflow_pop(int i)
 {

 	if (control_word & CW_Invalid) {
 		/* The masked response */
 		FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
 		FPU_pop();
 	}

 	EXCEPTION(EX_StackUnder);

 	return;

 }
	// SPDX-License-Identifier: GPL-2.0
	/*---------------------------------------------------------------------------+
	\| errors.c \|
	\| \|
	\| The error handling functions for wm-FPU-emu \|
	\| \|
	\| Copyright (C) 1992,1993,1994,1996 \|
	\| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia \|
	\| E-mail billm@jacobi.maths.monash.edu.au \|
	\| \|
	\| \|
	+---------------------------------------------------------------------------*/

	/*---------------------------------------------------------------------------+
	\| 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 <linux/signal.h>

	#include <linux/uaccess.h>

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

	/* */
	#undef PRINT_MESSAGES
	/* */

	#if 0
	void Un_impl(void)
	{
	u_char byte1, FPU_modrm;
	unsigned long address = FPU_ORIG_EIP;

	RE_ENTRANT_CHECK_OFF;
	/* No need to check access_ok(), we have previously fetched these bytes. */
	printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *)address);
	if (FPU_CS == __USER_CS) {
	while (1) {
	FPU_get_user(byte1, (u_char __user *) address);
	if ((byte1 & 0xf8) == 0xd8)
	break;
	printk("[%02x]", byte1);
	address++;
	}
	printk("%02x ", byte1);
	FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);

	if (FPU_modrm >= 0300)
	printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8,
	FPU_modrm & 7);
	else
	printk("/%d\n", (FPU_modrm >> 3) & 7);
	} else {
	printk("cs selector = %04x\n", FPU_CS);
	}

	RE_ENTRANT_CHECK_ON;

	EXCEPTION(EX_Invalid);

	}
	#endif /* 0 */

	/*
	Called for opcodes which are illegal and which are known to result in a
	SIGILL with a real 80486.
	*/
	void FPU_illegal(void)
	{
	math_abort(FPU_info, SIGILL);
	}

	void FPU_printall(void)
	{
	int i;
	static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty",
	"DeNorm", "Inf", "NaN"
	};
	u_char byte1, FPU_modrm;
	unsigned long address = FPU_ORIG_EIP;

	RE_ENTRANT_CHECK_OFF;
	/* No need to check access_ok(), we have previously fetched these bytes. */
	printk("At %p:", (void *)address);
	if (FPU_CS == __USER_CS) {
	#define MAX_PRINTED_BYTES 20
	for (i = 0; i < MAX_PRINTED_BYTES; i++) {
	FPU_get_user(byte1, (u_char __user *) address);
	if ((byte1 & 0xf8) == 0xd8) {
	printk(" %02x", byte1);
	break;
	}
	printk(" [%02x]", byte1);
	address++;
	}
	if (i == MAX_PRINTED_BYTES)
	printk(" [more..]\n");
	else {
	FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);

	if (FPU_modrm >= 0300)
	printk(" %02x (%02x+%d)\n", FPU_modrm,
	FPU_modrm & 0xf8, FPU_modrm & 7);
	else
	printk(" /%d, mod=%d rm=%d\n",
	(FPU_modrm >> 3) & 7,
	(FPU_modrm >> 6) & 3, FPU_modrm & 7);
	}
	} else {
	printk("%04x\n", FPU_CS);
	}

	partial_status = status_word();

	#ifdef DEBUGGING
	if (partial_status & SW_Backward)
	printk("SW: backward compatibility\n");
	if (partial_status & SW_C3)
	printk("SW: condition bit 3\n");
	if (partial_status & SW_C2)
	printk("SW: condition bit 2\n");
	if (partial_status & SW_C1)
	printk("SW: condition bit 1\n");
	if (partial_status & SW_C0)
	printk("SW: condition bit 0\n");
	if (partial_status & SW_Summary)
	printk("SW: exception summary\n");
	if (partial_status & SW_Stack_Fault)
	printk("SW: stack fault\n");
	if (partial_status & SW_Precision)
	printk("SW: loss of precision\n");
	if (partial_status & SW_Underflow)
	printk("SW: underflow\n");
	if (partial_status & SW_Overflow)
	printk("SW: overflow\n");
	if (partial_status & SW_Zero_Div)
	printk("SW: divide by zero\n");
	if (partial_status & SW_Denorm_Op)
	printk("SW: denormalized operand\n");
	if (partial_status & SW_Invalid)
	printk("SW: invalid operation\n");
	#endif /* DEBUGGING */

	printk(" SW: b=%d st=%d es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n", partial_status & 0x8000 ? 1 : 0, /* busy */
	(partial_status & 0x3800) >> 11, /* stack top pointer */
	partial_status & 0x80 ? 1 : 0, /* Error summary status */
	partial_status & 0x40 ? 1 : 0, /* Stack flag */
	partial_status & SW_C3 ? 1 : 0, partial_status & SW_C2 ? 1 : 0, /* cc */
	partial_status & SW_C1 ? 1 : 0, partial_status & SW_C0 ? 1 : 0, /* cc */
	partial_status & SW_Precision ? 1 : 0,
	partial_status & SW_Underflow ? 1 : 0,
	partial_status & SW_Overflow ? 1 : 0,
	partial_status & SW_Zero_Div ? 1 : 0,
	partial_status & SW_Denorm_Op ? 1 : 0,
	partial_status & SW_Invalid ? 1 : 0);

	printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d ef=%d%d%d%d%d%d\n",
	control_word & 0x1000 ? 1 : 0,
	(control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
	(control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
	control_word & 0x80 ? 1 : 0,
	control_word & SW_Precision ? 1 : 0,
	control_word & SW_Underflow ? 1 : 0,
	control_word & SW_Overflow ? 1 : 0,
	control_word & SW_Zero_Div ? 1 : 0,
	control_word & SW_Denorm_Op ? 1 : 0,
	control_word & SW_Invalid ? 1 : 0);

	for (i = 0; i < 8; i++) {
	FPU_REG *r = &st(i);
	u_char tagi = FPU_gettagi(i);
	switch (tagi) {
	case TAG_Empty:
	continue;
	break;
	case TAG_Zero:
	case TAG_Special:
	tagi = FPU_Special(r);
	case TAG_Valid:
	printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6d ", i,
	getsign(r) ? '-' : '+',
	(long)(r->sigh >> 16),
	(long)(r->sigh & 0xFFFF),
	(long)(r->sigl >> 16),
	(long)(r->sigl & 0xFFFF),
	exponent(r) - EXP_BIAS + 1);
	break;
	default:
	printk("Whoops! Error in errors.c: tag%d is %d ", i,
	tagi);
	continue;
	break;
	}
	printk("%s\n", tag_desc[(int)(unsigned)tagi]);
	}

	RE_ENTRANT_CHECK_ON;

	}

	static struct {
	int type;
	const char *name;
	} exception_names[] = {
	{
	EX_StackOver, "stack overflow"}, {
	EX_StackUnder, "stack underflow"}, {
	EX_Precision, "loss of precision"}, {
	EX_Underflow, "underflow"}, {
	EX_Overflow, "overflow"}, {
	EX_ZeroDiv, "divide by zero"}, {
	EX_Denormal, "denormalized operand"}, {
	EX_Invalid, "invalid operation"}, {
	EX_INTERNAL, "INTERNAL BUG in " FPU_VERSION}, {
	0, NULL}
	};

	/*
	EX_INTERNAL is always given with a code which indicates where the
	error was detected.

	Internal error types:
	0x14 in fpu_etc.c
	0x1nn in a *.c file:
	0x101 in reg_add_sub.c
	0x102 in reg_mul.c
	0x104 in poly_atan.c
	0x105 in reg_mul.c
	0x107 in fpu_trig.c
	0x108 in reg_compare.c
	0x109 in reg_compare.c
	0x110 in reg_add_sub.c
	0x111 in fpe_entry.c
	0x112 in fpu_trig.c
	0x113 in errors.c
	0x115 in fpu_trig.c
	0x116 in fpu_trig.c
	0x117 in fpu_trig.c
	0x118 in fpu_trig.c
	0x119 in fpu_trig.c
	0x120 in poly_atan.c
	0x121 in reg_compare.c
	0x122 in reg_compare.c
	0x123 in reg_compare.c
	0x125 in fpu_trig.c
	0x126 in fpu_entry.c
	0x127 in poly_2xm1.c
	0x128 in fpu_entry.c
	0x129 in fpu_entry.c
	0x130 in get_address.c
	0x131 in get_address.c
	0x132 in get_address.c
	0x133 in get_address.c
	0x140 in load_store.c
	0x141 in load_store.c
	0x150 in poly_sin.c
	0x151 in poly_sin.c
	0x160 in reg_ld_str.c
	0x161 in reg_ld_str.c
	0x162 in reg_ld_str.c
	0x163 in reg_ld_str.c
	0x164 in reg_ld_str.c
	0x170 in fpu_tags.c
	0x171 in fpu_tags.c
	0x172 in fpu_tags.c
	0x180 in reg_convert.c
	0x2nn in an *.S file:
	0x201 in reg_u_add.S
	0x202 in reg_u_div.S
	0x203 in reg_u_div.S
	0x204 in reg_u_div.S
	0x205 in reg_u_mul.S
	0x206 in reg_u_sub.S
	0x207 in wm_sqrt.S
	0x208 in reg_div.S
	0x209 in reg_u_sub.S
	0x210 in reg_u_sub.S
	0x211 in reg_u_sub.S
	0x212 in reg_u_sub.S
	0x213 in wm_sqrt.S
	0x214 in wm_sqrt.S
	0x215 in wm_sqrt.S
	0x220 in reg_norm.S
	0x221 in reg_norm.S
	0x230 in reg_round.S
	0x231 in reg_round.S
	0x232 in reg_round.S
	0x233 in reg_round.S
	0x234 in reg_round.S
	0x235 in reg_round.S
	0x236 in reg_round.S
	0x240 in div_Xsig.S
	0x241 in div_Xsig.S
	0x242 in div_Xsig.S
	*/

	asmlinkage __visible void FPU_exception(int n)
	{
	int i, int_type;

	int_type = 0; /* Needed only to stop compiler warnings */
	if (n & EX_INTERNAL) {
	int_type = n - EX_INTERNAL;
	n = EX_INTERNAL;
	/* Set lots of exception bits! */
	partial_status \|= (SW_Exc_Mask \| SW_Summary \| SW_Backward);
	} else {
	/* Extract only the bits which we use to set the status word */
	n &= (SW_Exc_Mask);
	/* Set the corresponding exception bit */
	partial_status \|= n;
	/* Set summary bits iff exception isn't masked */
	if (partial_status & ~control_word & CW_Exceptions)
	partial_status \|= (SW_Summary \| SW_Backward);
	if (n & (SW_Stack_Fault \| EX_Precision)) {
	if (!(n & SW_C1))
	/* This bit distinguishes over- from underflow for a stack fault,
	and roundup from round-down for precision loss. */
	partial_status &= ~SW_C1;
	}
	}

	RE_ENTRANT_CHECK_OFF;
	if ((~control_word & n & CW_Exceptions) \|\| (n == EX_INTERNAL)) {
	/* Get a name string for error reporting */
	for (i = 0; exception_names[i].type; i++)
	if ((exception_names[i].type & n) ==
	exception_names[i].type)
	break;

	if (exception_names[i].type) {
	#ifdef PRINT_MESSAGES
	printk("FP Exception: %s!\n", exception_names[i].name);
	#endif /* PRINT_MESSAGES */
	} else
	printk("FPU emulator: Unknown Exception: 0x%04x!\n", n);

	if (n == EX_INTERNAL) {
	printk("FPU emulator: Internal error type 0x%04x\n",
	int_type);
	FPU_printall();
	}
	#ifdef PRINT_MESSAGES
	else
	FPU_printall();
	#endif /* PRINT_MESSAGES */

	/*
	* The 80486 generates an interrupt on the next non-control FPU
	* instruction. So we need some means of flagging it.
	* We use the ES (Error Summary) bit for this.
	*/
	}
	RE_ENTRANT_CHECK_ON;

	#ifdef __DEBUG__
	math_abort(FPU_info, SIGFPE);
	#endif /* __DEBUG__ */

	}

	/* Real operation attempted on a NaN. */
	/* Returns < 0 if the exception is unmasked */
	int real_1op_NaN(FPU_REG *a)
	{
	int signalling, isNaN;

	isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000);

	/* The default result for the case of two "equal" NaNs (signs may
	differ) is chosen to reproduce 80486 behaviour */
	signalling = isNaN && !(a->sigh & 0x40000000);

	if (!signalling) {
	if (!isNaN) { /* pseudo-NaN, or other unsupported? */
	if (control_word & CW_Invalid) {
	/* Masked response */
	reg_copy(&CONST_QNaN, a);
	}
	EXCEPTION(EX_Invalid);
	return (!(control_word & CW_Invalid) ? FPU_Exception :
	0) \| TAG_Special;
	}
	return TAG_Special;
	}

	if (control_word & CW_Invalid) {
	/* The masked response */
	if (!(a->sigh & 0x80000000)) { /* pseudo-NaN ? */
	reg_copy(&CONST_QNaN, a);
	}
	/* ensure a Quiet NaN */
	a->sigh \|= 0x40000000;
	}

	EXCEPTION(EX_Invalid);

	return (!(control_word & CW_Invalid) ? FPU_Exception : 0) \| TAG_Special;
	}

	/* Real operation attempted on two operands, one a NaN. */
	/* Returns < 0 if the exception is unmasked */
	int real_2op_NaN(FPU_REG const *b, u_char tagb,
	int deststnr, FPU_REG const *defaultNaN)
	{
	FPU_REG *dest = &st(deststnr);
	FPU_REG const *a = dest;
	u_char taga = FPU_gettagi(deststnr);
	FPU_REG const *x;
	int signalling, unsupported;

	if (taga == TAG_Special)
	taga = FPU_Special(a);
	if (tagb == TAG_Special)
	tagb = FPU_Special(b);

	/* TW_NaN is also used for unsupported data types. */
	unsupported = ((taga == TW_NaN)
	&& !((exponent(a) == EXP_OVER)
	&& (a->sigh & 0x80000000)))
	\|\| ((tagb == TW_NaN)
	&& !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)));
	if (unsupported) {
	if (control_word & CW_Invalid) {
	/* Masked response */
	FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
	}
	EXCEPTION(EX_Invalid);
	return (!(control_word & CW_Invalid) ? FPU_Exception : 0) \|
	TAG_Special;
	}

	if (taga == TW_NaN) {
	x = a;
	if (tagb == TW_NaN) {
	signalling = !(a->sigh & b->sigh & 0x40000000);
	if (significand(b) > significand(a))
	x = b;
	else if (significand(b) == significand(a)) {
	/* The default result for the case of two "equal" NaNs (signs may
	differ) is chosen to reproduce 80486 behaviour */
	x = defaultNaN;
	}
	} else {
	/* return the quiet version of the NaN in a */
	signalling = !(a->sigh & 0x40000000);
	}
	} else
	#ifdef PARANOID
	if (tagb == TW_NaN)
	#endif /* PARANOID */
	{
	signalling = !(b->sigh & 0x40000000);
	x = b;
	}
	#ifdef PARANOID
	else {
	signalling = 0;
	EXCEPTION(EX_INTERNAL \| 0x113);
	x = &CONST_QNaN;
	}
	#endif /* PARANOID */

	if ((!signalling) \|\| (control_word & CW_Invalid)) {
	if (!x)
	x = b;

	if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */
	x = &CONST_QNaN;

	FPU_copy_to_regi(x, TAG_Special, deststnr);

	if (!signalling)
	return TAG_Special;

	/* ensure a Quiet NaN */
	dest->sigh \|= 0x40000000;
	}

	EXCEPTION(EX_Invalid);

	return (!(control_word & CW_Invalid) ? FPU_Exception : 0) \| TAG_Special;
	}

	/* Invalid arith operation on Valid registers */
	/* Returns < 0 if the exception is unmasked */
	asmlinkage __visible int arith_invalid(int deststnr)
	{

	EXCEPTION(EX_Invalid);

	if (control_word & CW_Invalid) {
	/* The masked response */
	FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
	}

	return (!(control_word & CW_Invalid) ? FPU_Exception : 0) \| TAG_Valid;

	}

	/* Divide a finite number by zero */
	asmlinkage __visible int FPU_divide_by_zero(int deststnr, u_char sign)
	{
	FPU_REG *dest = &st(deststnr);
	int tag = TAG_Valid;

	if (control_word & CW_ZeroDiv) {
	/* The masked response */
	FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr);
	setsign(dest, sign);
	tag = TAG_Special;
	}

	EXCEPTION(EX_ZeroDiv);

	return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) \| tag;

	}

	/* This may be called often, so keep it lean */
	int set_precision_flag(int flags)
	{
	if (control_word & CW_Precision) {
	partial_status &= ~(SW_C1 & flags);
	partial_status \|= flags; /* The masked response */
	return 0;
	} else {
	EXCEPTION(flags);
	return 1;
	}
	}

	/* This may be called often, so keep it lean */
	asmlinkage __visible void set_precision_flag_up(void)
	{
	if (control_word & CW_Precision)
	partial_status \|= (SW_Precision \| SW_C1); /* The masked response */
	else
	EXCEPTION(EX_Precision \| SW_C1);
	}

	/* This may be called often, so keep it lean */
	asmlinkage __visible void set_precision_flag_down(void)
	{
	if (control_word & CW_Precision) { /* The masked response */
	partial_status &= ~SW_C1;
	partial_status \|= SW_Precision;
	} else
	EXCEPTION(EX_Precision);
	}

	asmlinkage __visible int denormal_operand(void)
	{
	if (control_word & CW_Denormal) { /* The masked response */
	partial_status \|= SW_Denorm_Op;
	return TAG_Special;
	} else {
	EXCEPTION(EX_Denormal);
	return TAG_Special \| FPU_Exception;
	}
	}

	asmlinkage __visible int arith_overflow(FPU_REG *dest)
	{
	int tag = TAG_Valid;

	if (control_word & CW_Overflow) {
	/* The masked response */
	/* ###### The response here depends upon the rounding mode */
	reg_copy(&CONST_INF, dest);
	tag = TAG_Special;
	} else {
	/* Subtract the magic number from the exponent */
	addexponent(dest, (-3 * (1 << 13)));
	}

	EXCEPTION(EX_Overflow);
	if (control_word & CW_Overflow) {
	/* The overflow exception is masked. */
	/* By definition, precision is lost.
	The roundup bit (C1) is also set because we have
	"rounded" upwards to Infinity. */
	EXCEPTION(EX_Precision \| SW_C1);
	return tag;
	}

	return tag;

	}

	asmlinkage __visible int arith_underflow(FPU_REG *dest)
	{
	int tag = TAG_Valid;

	if (control_word & CW_Underflow) {
	/* The masked response */
	if (exponent16(dest) <= EXP_UNDER - 63) {
	reg_copy(&CONST_Z, dest);
	partial_status &= ~SW_C1; /* Round down. */
	tag = TAG_Zero;
	} else {
	stdexp(dest);
	}
	} else {
	/* Add the magic number to the exponent. */
	addexponent(dest, (3 * (1 << 13)) + EXTENDED_Ebias);
	}

	EXCEPTION(EX_Underflow);
	if (control_word & CW_Underflow) {
	/* The underflow exception is masked. */
	EXCEPTION(EX_Precision);
	return tag;
	}

	return tag;

	}

	void FPU_stack_overflow(void)
	{

	if (control_word & CW_Invalid) {
	/* The masked response */
	top--;
	FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
	}

	EXCEPTION(EX_StackOver);

	return;

	}

	void FPU_stack_underflow(void)
	{

	if (control_word & CW_Invalid) {
	/* The masked response */
	FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
	}

	EXCEPTION(EX_StackUnder);

	return;

	}

	void FPU_stack_underflow_i(int i)
	{

	if (control_word & CW_Invalid) {
	/* The masked response */
	FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
	}

	EXCEPTION(EX_StackUnder);

	return;

	}

	void FPU_stack_underflow_pop(int i)
	{

	if (control_word & CW_Invalid) {
	/* The masked response */
	FPU_copy_to_regi(&CONST_QNaN, TAG_Special, i);
	FPU_pop();
	}

	EXCEPTION(EX_StackUnder);

	return;

	}