358 lines
9.2 KiB
C
358 lines
9.2 KiB
C
/* Intel 386 stuff.
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Copyright (C) 1988, 1989 Free Software Foundation, Inc.
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This file is part of GDB.
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GDB is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 1, or (at your option)
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any later version.
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GDB is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GDB; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include <stdio.h>
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#include "defs.h"
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#include "param.h"
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#include "frame.h"
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#include "inferior.h"
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#include "gdbcore.h"
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#ifdef USG
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#include <sys/types.h>
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#endif
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#include <sys/param.h>
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#include <sys/dir.h>
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#include <signal.h>
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#include <sys/user.h>
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#include <sys/ioctl.h>
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#include <fcntl.h>
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <sys/reg.h>
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/* this table must line up with REGISTER_NAMES in m-i386.h */
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/* symbols like 'EAX' come from <sys/reg.h> */
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static int regmap[] =
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{
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EAX, ECX, EDX, EBX,
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UESP, EBP, ESI, EDI,
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EIP, EFL, CS, SS,
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DS, ES, FS, GS,
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};
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/* blockend is the value of u.u_ar0, and points to the
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* place where GS is stored
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*/
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i386_register_u_addr (blockend, regnum)
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{
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#if 0
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/* this will be needed if fp registers are reinstated */
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/* for now, you can look at them with 'info float'
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* sys5 wont let you change them with ptrace anyway
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*/
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if (regnum >= FP0_REGNUM && regnum <= FP7_REGNUM)
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{
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int ubase, fpstate;
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struct user u;
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ubase = blockend + 4 * (SS + 1) - KSTKSZ;
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fpstate = ubase + ((char *)&u.u_fpstate - (char *)&u);
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return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
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}
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else
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#endif
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return (blockend + 4 * regmap[regnum]);
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}
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/* This is broken for cross debugging. Possible solutions are:
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1. Don't worry about whether the thing compiles for cross-debugging.
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Go ahead and call them from i386-tdep.c.
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1a. Same thing but use some macros in xm-i386.h so that gdb will
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compile for cross-debugging but just give an error (or some such behavior)
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when you attempt to convert floats.
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2. Write a portable (in the sense of running on any machine; it would
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always be for i387 floating-point formats) extended<->double converter
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(which just deals with the values as arrays of char).
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3. Assume the host machine has *some* IEEE chip. However, IEEE does
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not standardize formats for extended floats (387 is 10 bytes, 68881 is
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12 bytes), so this won't work. */
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i387_to_double (from, to)
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char *from;
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char *to;
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{
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long *lp;
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/* push extended mode on 387 stack, then pop in double mode
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*
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* first, set exception masks so no error is generated -
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* number will be rounded to inf or 0, if necessary
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*/
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asm ("pushl %eax"); /* grab a stack slot */
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asm ("fstcw (%esp)"); /* get 387 control word */
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asm ("movl (%esp),%eax"); /* save old value */
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asm ("orl $0x3f,%eax"); /* mask all exceptions */
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asm ("pushl %eax");
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asm ("fldcw (%esp)"); /* load new value into 387 */
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asm ("movl 8(%ebp),%eax");
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asm ("fldt (%eax)"); /* push extended number on 387 stack */
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asm ("fwait");
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asm ("movl 12(%ebp),%eax");
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asm ("fstpl (%eax)"); /* pop double */
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asm ("fwait");
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asm ("popl %eax"); /* flush modified control word */
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asm ("fnclex"); /* clear exceptions */
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asm ("fldcw (%esp)"); /* restore original control word */
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asm ("popl %eax"); /* flush saved copy */
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}
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double_to_i387 (from, to)
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char *from;
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char *to;
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{
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/* push double mode on 387 stack, then pop in extended mode
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* no errors are possible because every 64-bit pattern
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* can be converted to an extended
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*/
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asm ("movl 8(%ebp),%eax");
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asm ("fldl (%eax)");
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asm ("fwait");
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asm ("movl 12(%ebp),%eax");
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asm ("fstpt (%eax)");
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asm ("fwait");
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}
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struct env387
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{
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unsigned short control;
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unsigned short r0;
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unsigned short status;
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unsigned short r1;
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unsigned short tag;
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unsigned short r2;
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unsigned long eip;
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unsigned short code_seg;
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unsigned short opcode;
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unsigned long operand;
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unsigned short operand_seg;
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unsigned short r3;
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unsigned char regs[8][10];
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};
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static
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print_387_control_word (control)
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unsigned short control;
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{
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printf ("control 0x%04x: ", control);
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printf ("compute to ");
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switch ((control >> 8) & 3)
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{
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case 0: printf ("24 bits; "); break;
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case 1: printf ("(bad); "); break;
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case 2: printf ("53 bits; "); break;
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case 3: printf ("64 bits; "); break;
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}
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printf ("round ");
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switch ((control >> 10) & 3)
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{
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case 0: printf ("NEAREST; "); break;
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case 1: printf ("DOWN; "); break;
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case 2: printf ("UP; "); break;
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case 3: printf ("CHOP; "); break;
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}
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if (control & 0x3f)
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{
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printf ("mask:");
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if (control & 0x0001) printf (" INVALID");
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if (control & 0x0002) printf (" DENORM");
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if (control & 0x0004) printf (" DIVZ");
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if (control & 0x0008) printf (" OVERF");
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if (control & 0x0010) printf (" UNDERF");
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if (control & 0x0020) printf (" LOS");
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printf (";");
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}
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printf ("\n");
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if (control & 0xe080) printf ("warning: reserved bits on 0x%x\n",
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control & 0xe080);
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}
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static
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print_387_status_word (status)
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unsigned short status;
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{
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printf ("status 0x%04x: ", status);
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if (status & 0xff)
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{
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printf ("exceptions:");
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if (status & 0x0001) printf (" INVALID");
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if (status & 0x0002) printf (" DENORM");
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if (status & 0x0004) printf (" DIVZ");
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if (status & 0x0008) printf (" OVERF");
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if (status & 0x0010) printf (" UNDERF");
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if (status & 0x0020) printf (" LOS");
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if (status & 0x0040) printf (" FPSTACK");
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printf ("; ");
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}
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printf ("flags: %d%d%d%d; ",
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(status & 0x4000) != 0,
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(status & 0x0400) != 0,
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(status & 0x0200) != 0,
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(status & 0x0100) != 0);
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printf ("top %d\n", (status >> 11) & 7);
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}
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static
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print_387_status (status, ep)
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unsigned short status;
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struct env387 *ep;
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{
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int i;
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int bothstatus;
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int top;
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int fpreg;
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unsigned char *p;
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bothstatus = ((status != 0) && (ep->status != 0));
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if (status != 0)
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{
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if (bothstatus)
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printf ("u: ");
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print_387_status_word (status);
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}
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if (ep->status != 0)
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{
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if (bothstatus)
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printf ("e: ");
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print_387_status_word (ep->status);
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}
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print_387_control_word (ep->control);
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printf ("last exception: ");
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printf ("opcode 0x%x; ", ep->opcode);
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printf ("pc 0x%x:0x%x; ", ep->code_seg, ep->eip);
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printf ("operand 0x%x:0x%x\n", ep->operand_seg, ep->operand);
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top = (ep->status >> 11) & 7;
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printf ("regno tag msb lsb value\n");
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for (fpreg = 7; fpreg >= 0; fpreg--)
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{
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double val;
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printf ("%s %d: ", fpreg == top ? "=>" : " ", fpreg);
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switch ((ep->tag >> (fpreg * 2)) & 3)
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{
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case 0: printf ("valid "); break;
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case 1: printf ("zero "); break;
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case 2: printf ("trap "); break;
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case 3: printf ("empty "); break;
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}
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for (i = 9; i >= 0; i--)
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printf ("%02x", ep->regs[fpreg][i]);
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i387_to_double (ep->regs[fpreg], (char *)&val);
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printf (" %g\n", val);
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}
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if (ep->r0)
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printf ("warning: reserved0 is 0x%x\n", ep->r0);
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if (ep->r1)
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printf ("warning: reserved1 is 0x%x\n", ep->r1);
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if (ep->r2)
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printf ("warning: reserved2 is 0x%x\n", ep->r2);
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if (ep->r3)
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printf ("warning: reserved3 is 0x%x\n", ep->r3);
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}
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#ifndef U_FPSTATE
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#define U_FPSTATE(u) u.u_fpstate
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#endif
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i386_float_info ()
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{
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struct user u; /* just for address computations */
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int i;
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/* fpstate defined in <sys/user.h> */
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struct fpstate *fpstatep;
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char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
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unsigned int uaddr;
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char fpvalid;
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unsigned int rounded_addr;
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unsigned int rounded_size;
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extern int corechan;
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int skip;
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uaddr = (char *)&u.u_fpvalid - (char *)&u;
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if (have_inferior_p())
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{
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unsigned int data;
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unsigned int mask;
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rounded_addr = uaddr & -sizeof (int);
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data = ptrace (3, inferior_pid, rounded_addr, 0);
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mask = 0xff << ((uaddr - rounded_addr) * 8);
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fpvalid = ((data & mask) != 0);
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}
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else
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{
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if (lseek (corechan, uaddr, 0) < 0)
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perror ("seek on core file");
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if (myread (corechan, &fpvalid, 1) < 0)
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perror ("read on core file");
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}
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if (fpvalid == 0)
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{
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printf ("no floating point status saved\n");
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return;
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}
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uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
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if (have_inferior_p ())
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{
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int *ip;
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rounded_addr = uaddr & -sizeof (int);
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rounded_size = (((uaddr + sizeof (struct fpstate)) - uaddr) +
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sizeof (int) - 1) / sizeof (int);
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skip = uaddr - rounded_addr;
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ip = (int *)buf;
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for (i = 0; i < rounded_size; i++)
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{
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*ip++ = ptrace (3, inferior_pid, rounded_addr, 0);
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rounded_addr += sizeof (int);
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}
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}
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else
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{
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if (lseek (corechan, uaddr, 0) < 0)
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perror_with_name ("seek on core file");
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if (myread (corechan, buf, sizeof (struct fpstate)) < 0)
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perror_with_name ("read from core file");
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skip = 0;
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}
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fpstatep = (struct fpstate *)(buf + skip);
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print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
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}
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