628 lines
16 KiB
C
628 lines
16 KiB
C
/*---------------------------------------------------------------------------+
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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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| Copyright (C) 1992,1993,1994 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
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| Australia. E-mail billm@vaxc.cc.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 <asm/segment.h>
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#include "fpu_system.h"
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#include "exception.h"
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#include "fpu_emu.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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void Un_impl(void)
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{
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unsigned 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 verify_area(), we have previously fetched these bytes. */
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printk("Unimplemented FPU Opcode at eip=%p : ", (void *) address);
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while ( 1 )
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{
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byte1 = get_fs_byte((unsigned char *) 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_modrm = get_fs_byte(1 + (unsigned char *) 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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RE_ENTRANT_CHECK_ON;
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EXCEPTION(EX_Invalid);
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}
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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 emu_printall()
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{
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int i;
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static char *tag_desc[] = { "Valid", "Zero", "ERROR", "ERROR",
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"DeNorm", "Inf", "NaN", "Empty" };
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unsigned 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 verify_area(), we have previously fetched these bytes. */
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printk("At %p: ", (void *) address);
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while ( 1 )
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{
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byte1 = get_fs_byte((unsigned char *) 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_modrm = get_fs_byte(1 + (unsigned char *) address);
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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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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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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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switch (r->tag)
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{
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case TW_Empty:
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continue;
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break;
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case TW_Zero:
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#if 0
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printk("st(%d) %c .0000 0000 0000 0000 ",
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i, r->sign ? '-' : '+');
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break;
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#endif
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case TW_Valid:
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case TW_NaN:
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/* case TW_Denormal: */
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case TW_Infinity:
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printk("st(%d) %c .%04lx %04lx %04lx %04lx e%+-6ld ", i,
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r->sign ? '-' : '+',
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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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r->exp - EXP_BIAS + 1);
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break;
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default:
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printk("Whoops! Error in errors.c ");
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break;
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}
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printk("%s\n", tag_desc[(int) (unsigned) r->tag]);
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}
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printk("[data] %c .%04lx %04lx %04lx %04lx e%+-6ld ",
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FPU_loaded_data.sign ? '-' : '+',
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(long)(FPU_loaded_data.sigh >> 16),
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(long)(FPU_loaded_data.sigh & 0xFFFF),
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(long)(FPU_loaded_data.sigl >> 16),
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(long)(FPU_loaded_data.sigl & 0xFFFF),
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FPU_loaded_data.exp - EXP_BIAS + 1);
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printk("%s\n", tag_desc[(int) (unsigned) FPU_loaded_data.tag]);
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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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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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0 in load_store.c
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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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0x103 in poly_sin.c
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0x104 in poly_atan.c
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0x105 in reg_mul.c
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0x106 in reg_ld_str.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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0x114 in reg_ld_str.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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0x2nn in an *.S file:
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0x201 in reg_u_add.S, reg_round.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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0x216 in reg_round.S
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0x217 in reg_round.S
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0x218 in reg_round.S
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0x220 in reg_norm.S
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0x221 in reg_norm.S
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*/
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void 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("FP emulator: Unknown Exception: 0x%04x!\n", n);
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if ( n == EX_INTERNAL )
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{
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printk("FP emulator: Internal error type 0x%04x\n", int_type);
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emu_printall();
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}
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#ifdef PRINT_MESSAGES
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else
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emu_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, assuming that
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* this is the way a real FPU does it (until I can check it out),
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* if not, then some method such as the following kludge might
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* be needed.
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*/
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/* regs[0].tag |= TW_FPU_Interrupt; */
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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 two operands, one a NaN. */
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/* Returns nz if the exception is unmasked */
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asmlinkage int real_2op_NaN(FPU_REG const *a, FPU_REG const *b, FPU_REG *dest)
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{
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FPU_REG const *x;
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int signalling;
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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 = a;
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if (a->tag == TW_NaN)
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{
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if (b->tag == TW_NaN)
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{
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signalling = !(a->sigh & b->sigh & 0x40000000);
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/* find the "larger" */
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if ( significand(a) < significand(b) )
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x = b;
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}
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else
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{
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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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}
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else
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#ifdef PARANOID
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if (b->tag == 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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{
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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 )
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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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reg_move(x, dest);
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return 0;
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}
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if ( control_word & CW_Invalid )
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{
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/* The masked response */
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if ( !(x->sigh & 0x80000000) ) /* pseudo-NaN ? */
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x = &CONST_QNaN;
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reg_move(x, dest);
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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);
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}
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/* Invalid arith operation on Valid registers */
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/* Returns nz if the exception is unmasked */
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asmlinkage int arith_invalid(FPU_REG *dest)
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{
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EXCEPTION(EX_Invalid);
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if ( control_word & CW_Invalid )
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{
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/* The masked response */
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reg_move(&CONST_QNaN, dest);
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}
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return !(control_word & CW_Invalid);
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}
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/* Divide a finite number by zero */
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asmlinkage int divide_by_zero(int sign, FPU_REG *dest)
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{
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if ( control_word & CW_ZeroDiv )
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{
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/* The masked response */
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reg_move(&CONST_INF, dest);
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dest->sign = (unsigned char)sign;
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}
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EXCEPTION(EX_ZeroDiv);
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return !(control_word & CW_ZeroDiv);
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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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{
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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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}
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else
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{
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exception(flags);
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return 1;
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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 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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/* This may be called often, so keep it lean */
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asmlinkage void set_precision_flag_down(void)
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{
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if ( control_word & CW_Precision )
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{ /* The masked response */
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partial_status &= ~SW_C1;
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partial_status |= SW_Precision;
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}
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else
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exception(EX_Precision);
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}
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asmlinkage int denormal_operand(void)
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{
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if ( control_word & CW_Denormal )
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{ /* The masked response */
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partial_status |= SW_Denorm_Op;
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return 0;
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}
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else
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{
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exception(EX_Denormal);
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return 1;
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}
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}
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asmlinkage int arith_overflow(FPU_REG *dest)
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{
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if ( control_word & CW_Overflow )
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{
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char sign;
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/* The masked response */
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/* ###### The response here depends upon the rounding mode */
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sign = dest->sign;
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reg_move(&CONST_INF, dest);
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dest->sign = sign;
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}
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else
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{
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/* Subtract the magic number from the exponent */
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dest->exp -= (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 !(control_word & CW_Precision);
|
|
}
|
|
|
|
return !(control_word & CW_Overflow);
|
|
|
|
}
|
|
|
|
|
|
asmlinkage int arith_underflow(FPU_REG *dest)
|
|
{
|
|
|
|
if ( control_word & CW_Underflow )
|
|
{
|
|
/* The masked response */
|
|
if ( dest->exp <= EXP_UNDER - 63 )
|
|
{
|
|
reg_move(&CONST_Z, dest);
|
|
partial_status &= ~SW_C1; /* Round down. */
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* Add the magic number to the exponent. */
|
|
dest->exp += (3 * (1 << 13));
|
|
}
|
|
|
|
EXCEPTION(EX_Underflow);
|
|
if ( control_word & CW_Underflow )
|
|
{
|
|
/* The underflow exception is masked. */
|
|
EXCEPTION(EX_Precision);
|
|
return !(control_word & CW_Precision);
|
|
}
|
|
|
|
return !(control_word & CW_Underflow);
|
|
|
|
}
|
|
|
|
|
|
void stack_overflow(void)
|
|
{
|
|
|
|
if ( control_word & CW_Invalid )
|
|
{
|
|
/* The masked response */
|
|
top--;
|
|
reg_move(&CONST_QNaN, FPU_st0_ptr = &st(0));
|
|
}
|
|
|
|
EXCEPTION(EX_StackOver);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
void stack_underflow(void)
|
|
{
|
|
|
|
if ( control_word & CW_Invalid )
|
|
{
|
|
/* The masked response */
|
|
reg_move(&CONST_QNaN, FPU_st0_ptr);
|
|
}
|
|
|
|
EXCEPTION(EX_StackUnder);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
void stack_underflow_i(int i)
|
|
{
|
|
|
|
if ( control_word & CW_Invalid )
|
|
{
|
|
/* The masked response */
|
|
reg_move(&CONST_QNaN, &(st(i)));
|
|
}
|
|
|
|
EXCEPTION(EX_StackUnder);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
void stack_underflow_pop(int i)
|
|
{
|
|
|
|
if ( control_word & CW_Invalid )
|
|
{
|
|
/* The masked response */
|
|
reg_move(&CONST_QNaN, &(st(i)));
|
|
pop();
|
|
}
|
|
|
|
EXCEPTION(EX_StackUnder);
|
|
|
|
return;
|
|
|
|
}
|
|
|