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739 lines
18 KiB
739 lines
18 KiB
/*---------------------------------------------------------------------------+
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| errors.c |
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| |
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| The error handling functions for wm-FPU-emu |
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| |
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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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+---------------------------------------------------------------------------*/
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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 <asm/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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{
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while ( 1 )
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{
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FPU_get_user(byte1, (u_char __user *) address);
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if ( (byte1 & 0xf8) == 0xd8 ) 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, FPU_modrm & 7);
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else
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printk("/%d\n", (FPU_modrm >> 3) & 7);
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}
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else
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{
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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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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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{
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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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{
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FPU_get_user(byte1, (u_char __user *) address);
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if ( (byte1 & 0xf8) == 0xd8 )
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{
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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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{
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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, 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, (FPU_modrm >> 6) & 3, FPU_modrm & 7);
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}
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}
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else
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{
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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 ) printk("SW: backward compatibility\n");
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if ( partial_status & SW_C3 ) printk("SW: condition bit 3\n");
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if ( partial_status & SW_C2 ) printk("SW: condition bit 2\n");
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if ( partial_status & SW_C1 ) printk("SW: condition bit 1\n");
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if ( partial_status & SW_C0 ) printk("SW: condition bit 0\n");
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if ( partial_status & SW_Summary ) printk("SW: exception summary\n");
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if ( partial_status & SW_Stack_Fault ) printk("SW: stack fault\n");
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if ( partial_status & SW_Precision ) printk("SW: loss of precision\n");
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if ( partial_status & SW_Underflow ) printk("SW: underflow\n");
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if ( partial_status & SW_Overflow ) printk("SW: overflow\n");
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if ( partial_status & SW_Zero_Div ) printk("SW: divide by zero\n");
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if ( partial_status & SW_Denorm_Op ) printk("SW: denormalized operand\n");
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if ( partial_status & SW_Invalid ) printk("SW: invalid operation\n");
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#endif /* DEBUGGING */
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printk(" SW: b=%d st=%ld es=%d sf=%d cc=%d%d%d%d ef=%d%d%d%d%d%d\n",
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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, partial_status & SW_Underflow?1:0,
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partial_status & SW_Overflow?1:0, partial_status & SW_Zero_Div?1:0,
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partial_status & SW_Denorm_Op?1:0, partial_status & SW_Invalid?1:0);
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printk(" CW: ic=%d rc=%ld%ld pc=%ld%ld 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, control_word & SW_Underflow?1:0,
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control_word & SW_Overflow?1:0, control_word & SW_Zero_Div?1:0,
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control_word & SW_Denorm_Op?1:0, control_word & SW_Invalid?1:0);
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for ( i = 0; i < 8; i++ )
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{
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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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{
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case TAG_Empty:
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continue;
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break;
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case TAG_Zero:
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case TAG_Special:
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tagi = FPU_Special(r);
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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, tagi);
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continue;
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break;
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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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{ 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 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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{
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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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}
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else
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{
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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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{
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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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{
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#ifdef PRINT_MESSAGES
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/* My message from the sponsor */
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printk(FPU_VERSION" "__DATE__" (C) W. Metzenthen.\n");
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#endif /* PRINT_MESSAGES */
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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) == exception_names[i].type )
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break;
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if (exception_names[i].type)
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{
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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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}
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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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{
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printk("FPU emulator: Internal error type 0x%04x\n", 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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/*
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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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|
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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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}
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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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|
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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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|
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if ( !signalling )
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{
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if ( !isNaN ) /* pseudo-NaN, or other unsupported? */
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{
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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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EXCEPTION(EX_Invalid);
|
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return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special;
|
|
}
|
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return TAG_Special;
|
|
}
|
|
|
|
if ( control_word & CW_Invalid )
|
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{
|
|
/* The masked response */
|
|
if ( !(a->sigh & 0x80000000) ) /* pseudo-NaN ? */
|
|
{
|
|
reg_copy(&CONST_QNaN, a);
|
|
}
|
|
/* 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;
|
|
}
|
|
|
|
|
|
/* 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)))
|
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|| ((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 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 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 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 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 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 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 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;
|
|
|
|
}
|
|
|
|
|