687 lines
18 KiB
C
687 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*---------------------------------------------------------------------------+
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| errors.c |
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| The error handling functions for wm-FPU-emu |
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| Copyright (C) 1992,1993,1994,1996 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
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| E-mail billm@jacobi.maths.monash.edu.au |
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+---------------------------------------------------------------------------*/
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/*---------------------------------------------------------------------------+
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| Note: |
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| The file contains code which accesses user memory. |
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| Emulator static data may change when user memory is accessed, due to |
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| other processes using the emulator while swapping is in progress. |
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+---------------------------------------------------------------------------*/
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#include <linux/signal.h>
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#include <linux/uaccess.h>
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#include "fpu_emu.h"
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#include "fpu_system.h"
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#include "exception.h"
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#include "status_w.h"
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#include "control_w.h"
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#include "reg_constant.h"
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#include "version.h"
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/* */
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#undef PRINT_MESSAGES
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/* */
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#if 0
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void Un_impl(void)
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{
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u_char byte1, FPU_modrm;
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unsigned long address = FPU_ORIG_EIP;
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RE_ENTRANT_CHECK_OFF;
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/* No need to check access_ok(), we have previously fetched these bytes. */
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printk("Unimplemented FPU Opcode at eip=%p : ", (void __user *)address);
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if (FPU_CS == __USER_CS) {
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while (1) {
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FPU_get_user(byte1, (u_char __user *) address);
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if ((byte1 & 0xf8) == 0xd8)
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break;
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printk("[%02x]", byte1);
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address++;
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}
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printk("%02x ", byte1);
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FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
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if (FPU_modrm >= 0300)
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printk("%02x (%02x+%d)\n", FPU_modrm, FPU_modrm & 0xf8,
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FPU_modrm & 7);
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else
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printk("/%d\n", (FPU_modrm >> 3) & 7);
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} else {
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printk("cs selector = %04x\n", FPU_CS);
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}
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RE_ENTRANT_CHECK_ON;
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EXCEPTION(EX_Invalid);
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}
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#endif /* 0 */
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/*
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Called for opcodes which are illegal and which are known to result in a
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SIGILL with a real 80486.
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*/
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void FPU_illegal(void)
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{
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math_abort(FPU_info, SIGILL);
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}
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void FPU_printall(void)
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{
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int i;
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static const char *tag_desc[] = { "Valid", "Zero", "ERROR", "Empty",
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"DeNorm", "Inf", "NaN"
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};
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u_char byte1, FPU_modrm;
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unsigned long address = FPU_ORIG_EIP;
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RE_ENTRANT_CHECK_OFF;
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/* No need to check access_ok(), we have previously fetched these bytes. */
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printk("At %p:", (void *)address);
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if (FPU_CS == __USER_CS) {
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#define MAX_PRINTED_BYTES 20
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for (i = 0; i < MAX_PRINTED_BYTES; i++) {
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FPU_get_user(byte1, (u_char __user *) address);
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if ((byte1 & 0xf8) == 0xd8) {
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printk(" %02x", byte1);
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break;
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}
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printk(" [%02x]", byte1);
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address++;
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}
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if (i == MAX_PRINTED_BYTES)
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printk(" [more..]\n");
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else {
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FPU_get_user(FPU_modrm, 1 + (u_char __user *) address);
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if (FPU_modrm >= 0300)
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printk(" %02x (%02x+%d)\n", FPU_modrm,
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FPU_modrm & 0xf8, FPU_modrm & 7);
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else
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printk(" /%d, mod=%d rm=%d\n",
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(FPU_modrm >> 3) & 7,
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(FPU_modrm >> 6) & 3, FPU_modrm & 7);
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}
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} else {
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printk("%04x\n", FPU_CS);
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}
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partial_status = status_word();
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#ifdef DEBUGGING
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if (partial_status & SW_Backward)
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printk("SW: backward compatibility\n");
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if (partial_status & SW_C3)
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printk("SW: condition bit 3\n");
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if (partial_status & SW_C2)
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printk("SW: condition bit 2\n");
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if (partial_status & SW_C1)
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printk("SW: condition bit 1\n");
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if (partial_status & SW_C0)
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printk("SW: condition bit 0\n");
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if (partial_status & SW_Summary)
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printk("SW: exception summary\n");
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if (partial_status & SW_Stack_Fault)
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printk("SW: stack fault\n");
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if (partial_status & SW_Precision)
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printk("SW: loss of precision\n");
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if (partial_status & SW_Underflow)
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printk("SW: underflow\n");
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if (partial_status & SW_Overflow)
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printk("SW: overflow\n");
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if (partial_status & SW_Zero_Div)
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printk("SW: divide by zero\n");
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if (partial_status & SW_Denorm_Op)
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printk("SW: denormalized operand\n");
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if (partial_status & SW_Invalid)
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printk("SW: invalid operation\n");
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#endif /* DEBUGGING */
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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 */
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(partial_status & 0x3800) >> 11, /* stack top pointer */
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partial_status & 0x80 ? 1 : 0, /* Error summary status */
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partial_status & 0x40 ? 1 : 0, /* Stack flag */
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partial_status & SW_C3 ? 1 : 0, partial_status & SW_C2 ? 1 : 0, /* cc */
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partial_status & SW_C1 ? 1 : 0, partial_status & SW_C0 ? 1 : 0, /* cc */
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partial_status & SW_Precision ? 1 : 0,
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partial_status & SW_Underflow ? 1 : 0,
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partial_status & SW_Overflow ? 1 : 0,
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partial_status & SW_Zero_Div ? 1 : 0,
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partial_status & SW_Denorm_Op ? 1 : 0,
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partial_status & SW_Invalid ? 1 : 0);
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printk(" CW: ic=%d rc=%d%d pc=%d%d iem=%d ef=%d%d%d%d%d%d\n",
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control_word & 0x1000 ? 1 : 0,
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(control_word & 0x800) >> 11, (control_word & 0x400) >> 10,
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(control_word & 0x200) >> 9, (control_word & 0x100) >> 8,
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control_word & 0x80 ? 1 : 0,
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control_word & SW_Precision ? 1 : 0,
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control_word & SW_Underflow ? 1 : 0,
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control_word & SW_Overflow ? 1 : 0,
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control_word & SW_Zero_Div ? 1 : 0,
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control_word & SW_Denorm_Op ? 1 : 0,
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control_word & SW_Invalid ? 1 : 0);
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for (i = 0; i < 8; i++) {
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FPU_REG *r = &st(i);
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u_char tagi = FPU_gettagi(i);
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switch (tagi) {
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case TAG_Empty:
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continue;
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case TAG_Zero:
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case TAG_Special:
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/* Update tagi for the printk below */
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tagi = FPU_Special(r);
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fallthrough;
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case TAG_Valid:
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printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6d ", i,
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getsign(r) ? '-' : '+',
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(long)(r->sigh >> 16),
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(long)(r->sigh & 0xFFFF),
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(long)(r->sigl >> 16),
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(long)(r->sigl & 0xFFFF),
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exponent(r) - EXP_BIAS + 1);
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break;
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default:
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printk("Whoops! Error in errors.c: tag%d is %d ", i,
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tagi);
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continue;
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}
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printk("%s\n", tag_desc[(int)(unsigned)tagi]);
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}
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RE_ENTRANT_CHECK_ON;
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}
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static struct {
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int type;
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const char *name;
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} exception_names[] = {
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{
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EX_StackOver, "stack overflow"}, {
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EX_StackUnder, "stack underflow"}, {
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EX_Precision, "loss of precision"}, {
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EX_Underflow, "underflow"}, {
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EX_Overflow, "overflow"}, {
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EX_ZeroDiv, "divide by zero"}, {
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EX_Denormal, "denormalized operand"}, {
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EX_Invalid, "invalid operation"}, {
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EX_INTERNAL, "INTERNAL BUG in " FPU_VERSION}, {
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0, NULL}
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};
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/*
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EX_INTERNAL is always given with a code which indicates where the
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error was detected.
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Internal error types:
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0x14 in fpu_etc.c
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0x1nn in a *.c file:
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0x101 in reg_add_sub.c
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0x102 in reg_mul.c
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0x104 in poly_atan.c
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0x105 in reg_mul.c
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0x107 in fpu_trig.c
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0x108 in reg_compare.c
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0x109 in reg_compare.c
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0x110 in reg_add_sub.c
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0x111 in fpe_entry.c
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0x112 in fpu_trig.c
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0x113 in errors.c
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0x115 in fpu_trig.c
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0x116 in fpu_trig.c
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0x117 in fpu_trig.c
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0x118 in fpu_trig.c
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0x119 in fpu_trig.c
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0x120 in poly_atan.c
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0x121 in reg_compare.c
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0x122 in reg_compare.c
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0x123 in reg_compare.c
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0x125 in fpu_trig.c
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0x126 in fpu_entry.c
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0x127 in poly_2xm1.c
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0x128 in fpu_entry.c
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0x129 in fpu_entry.c
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0x130 in get_address.c
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0x131 in get_address.c
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0x132 in get_address.c
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0x133 in get_address.c
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0x140 in load_store.c
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0x141 in load_store.c
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0x150 in poly_sin.c
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0x151 in poly_sin.c
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0x160 in reg_ld_str.c
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0x161 in reg_ld_str.c
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0x162 in reg_ld_str.c
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0x163 in reg_ld_str.c
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0x164 in reg_ld_str.c
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0x170 in fpu_tags.c
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0x171 in fpu_tags.c
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0x172 in fpu_tags.c
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0x180 in reg_convert.c
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0x2nn in an *.S file:
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0x201 in reg_u_add.S
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0x202 in reg_u_div.S
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0x203 in reg_u_div.S
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0x204 in reg_u_div.S
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0x205 in reg_u_mul.S
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0x206 in reg_u_sub.S
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0x207 in wm_sqrt.S
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0x208 in reg_div.S
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0x209 in reg_u_sub.S
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0x210 in reg_u_sub.S
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0x211 in reg_u_sub.S
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0x212 in reg_u_sub.S
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0x213 in wm_sqrt.S
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0x214 in wm_sqrt.S
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0x215 in wm_sqrt.S
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0x220 in reg_norm.S
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0x221 in reg_norm.S
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0x230 in reg_round.S
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0x231 in reg_round.S
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0x232 in reg_round.S
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0x233 in reg_round.S
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0x234 in reg_round.S
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0x235 in reg_round.S
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0x236 in reg_round.S
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0x240 in div_Xsig.S
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0x241 in div_Xsig.S
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0x242 in div_Xsig.S
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*/
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asmlinkage __visible void FPU_exception(int n)
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{
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int i, int_type;
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int_type = 0; /* Needed only to stop compiler warnings */
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if (n & EX_INTERNAL) {
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int_type = n - EX_INTERNAL;
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n = EX_INTERNAL;
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/* Set lots of exception bits! */
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partial_status |= (SW_Exc_Mask | SW_Summary | SW_Backward);
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} else {
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/* Extract only the bits which we use to set the status word */
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n &= (SW_Exc_Mask);
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/* Set the corresponding exception bit */
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partial_status |= n;
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/* Set summary bits iff exception isn't masked */
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if (partial_status & ~control_word & CW_Exceptions)
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partial_status |= (SW_Summary | SW_Backward);
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if (n & (SW_Stack_Fault | EX_Precision)) {
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if (!(n & SW_C1))
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/* This bit distinguishes over- from underflow for a stack fault,
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and roundup from round-down for precision loss. */
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partial_status &= ~SW_C1;
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}
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}
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RE_ENTRANT_CHECK_OFF;
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if ((~control_word & n & CW_Exceptions) || (n == EX_INTERNAL)) {
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/* Get a name string for error reporting */
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for (i = 0; exception_names[i].type; i++)
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if ((exception_names[i].type & n) ==
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exception_names[i].type)
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break;
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if (exception_names[i].type) {
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#ifdef PRINT_MESSAGES
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printk("FP Exception: %s!\n", exception_names[i].name);
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#endif /* PRINT_MESSAGES */
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} else
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printk("FPU emulator: Unknown Exception: 0x%04x!\n", n);
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if (n == EX_INTERNAL) {
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printk("FPU emulator: Internal error type 0x%04x\n",
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int_type);
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FPU_printall();
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}
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#ifdef PRINT_MESSAGES
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else
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FPU_printall();
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#endif /* PRINT_MESSAGES */
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/*
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* The 80486 generates an interrupt on the next non-control FPU
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* instruction. So we need some means of flagging it.
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* We use the ES (Error Summary) bit for this.
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*/
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}
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RE_ENTRANT_CHECK_ON;
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#ifdef __DEBUG__
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math_abort(FPU_info, SIGFPE);
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#endif /* __DEBUG__ */
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}
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/* Real operation attempted on a NaN. */
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/* Returns < 0 if the exception is unmasked */
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int real_1op_NaN(FPU_REG *a)
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{
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int signalling, isNaN;
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isNaN = (exponent(a) == EXP_OVER) && (a->sigh & 0x80000000);
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/* The default result for the case of two "equal" NaNs (signs may
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differ) is chosen to reproduce 80486 behaviour */
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signalling = isNaN && !(a->sigh & 0x40000000);
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if (!signalling) {
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if (!isNaN) { /* pseudo-NaN, or other unsupported? */
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if (control_word & CW_Invalid) {
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/* Masked response */
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reg_copy(&CONST_QNaN, a);
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}
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EXCEPTION(EX_Invalid);
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return (!(control_word & CW_Invalid) ? FPU_Exception :
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0) | TAG_Special;
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}
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return TAG_Special;
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}
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if (control_word & CW_Invalid) {
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/* The masked response */
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if (!(a->sigh & 0x80000000)) { /* pseudo-NaN ? */
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reg_copy(&CONST_QNaN, a);
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}
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/* ensure a Quiet NaN */
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a->sigh |= 0x40000000;
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}
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EXCEPTION(EX_Invalid);
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return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
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}
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/* Real operation attempted on two operands, one a NaN. */
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/* Returns < 0 if the exception is unmasked */
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int real_2op_NaN(FPU_REG const *b, u_char tagb,
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int deststnr, FPU_REG const *defaultNaN)
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{
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FPU_REG *dest = &st(deststnr);
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FPU_REG const *a = dest;
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u_char taga = FPU_gettagi(deststnr);
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FPU_REG const *x;
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int signalling, unsupported;
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if (taga == TAG_Special)
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taga = FPU_Special(a);
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if (tagb == TAG_Special)
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tagb = FPU_Special(b);
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/* TW_NaN is also used for unsupported data types. */
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unsupported = ((taga == TW_NaN)
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&& !((exponent(a) == EXP_OVER)
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&& (a->sigh & 0x80000000)))
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|| ((tagb == TW_NaN)
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&& !((exponent(b) == EXP_OVER) && (b->sigh & 0x80000000)));
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if (unsupported) {
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if (control_word & CW_Invalid) {
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/* Masked response */
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FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr);
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}
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EXCEPTION(EX_Invalid);
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return (!(control_word & CW_Invalid) ? FPU_Exception : 0) |
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TAG_Special;
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}
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if (taga == TW_NaN) {
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x = a;
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if (tagb == TW_NaN) {
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signalling = !(a->sigh & b->sigh & 0x40000000);
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if (significand(b) > significand(a))
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x = b;
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else if (significand(b) == significand(a)) {
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/* The default result for the case of two "equal" NaNs (signs may
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differ) is chosen to reproduce 80486 behaviour */
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x = defaultNaN;
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}
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} else {
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/* return the quiet version of the NaN in a */
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signalling = !(a->sigh & 0x40000000);
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}
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} else
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#ifdef PARANOID
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if (tagb == TW_NaN)
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#endif /* PARANOID */
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{
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signalling = !(b->sigh & 0x40000000);
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x = b;
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}
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#ifdef PARANOID
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else {
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signalling = 0;
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EXCEPTION(EX_INTERNAL | 0x113);
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x = &CONST_QNaN;
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}
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#endif /* PARANOID */
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if ((!signalling) || (control_word & CW_Invalid)) {
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if (!x)
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x = b;
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if (!(x->sigh & 0x80000000)) /* pseudo-NaN ? */
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x = &CONST_QNaN;
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FPU_copy_to_regi(x, TAG_Special, deststnr);
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if (!signalling)
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return TAG_Special;
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/* ensure a Quiet NaN */
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dest->sigh |= 0x40000000;
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}
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EXCEPTION(EX_Invalid);
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return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
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}
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/* Invalid arith operation on Valid registers */
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|
/* 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;
|
|
|
|
}
|