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686 lines
18 KiB
686 lines
18 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/*---------------------------------------------------------------------------+ |
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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 [email protected] | |
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| | |
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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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|
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#include <linux/signal.h> |
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|
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#include <linux/uaccess.h> |
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|
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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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/* */ |
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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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|
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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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|
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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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|
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if (!signalling) |
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return TAG_Special; |
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|
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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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|
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return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Special; |
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} |
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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 */ |
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asmlinkage __visible int arith_invalid(int deststnr) |
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{ |
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|
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EXCEPTION(EX_Invalid); |
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|
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if (control_word & CW_Invalid) { |
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/* The masked response */ |
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FPU_copy_to_regi(&CONST_QNaN, TAG_Special, deststnr); |
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} |
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|
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return (!(control_word & CW_Invalid) ? FPU_Exception : 0) | TAG_Valid; |
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|
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} |
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|
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/* Divide a finite number by zero */ |
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asmlinkage __visible int FPU_divide_by_zero(int deststnr, u_char sign) |
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{ |
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FPU_REG *dest = &st(deststnr); |
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int tag = TAG_Valid; |
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|
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if (control_word & CW_ZeroDiv) { |
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/* The masked response */ |
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FPU_copy_to_regi(&CONST_INF, TAG_Special, deststnr); |
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setsign(dest, sign); |
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tag = TAG_Special; |
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} |
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EXCEPTION(EX_ZeroDiv); |
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|
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return (!(control_word & CW_ZeroDiv) ? FPU_Exception : 0) | tag; |
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|
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} |
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|
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/* This may be called often, so keep it lean */ |
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int set_precision_flag(int flags) |
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{ |
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if (control_word & CW_Precision) { |
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partial_status &= ~(SW_C1 & flags); |
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partial_status |= flags; /* The masked response */ |
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return 0; |
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} else { |
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EXCEPTION(flags); |
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return 1; |
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} |
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} |
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|
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/* This may be called often, so keep it lean */ |
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asmlinkage __visible void set_precision_flag_up(void) |
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{ |
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if (control_word & CW_Precision) |
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partial_status |= (SW_Precision | SW_C1); /* The masked response */ |
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else |
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EXCEPTION(EX_Precision | SW_C1); |
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} |
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|
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/* This may be called often, so keep it lean */ |
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asmlinkage __visible void set_precision_flag_down(void) |
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{ |
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if (control_word & CW_Precision) { /* The masked response */ |
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partial_status &= ~SW_C1; |
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partial_status |= SW_Precision; |
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} else |
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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; |
|
|
|
}
|
|
|