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/*
* This is derived from i386-xdep.c
*/
/* Intel 386 stuff.
Copyright (C) 1988, 1989 Free Software Foundation, Inc.
This file is part of GDB.
GDB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 1, or (at your option)
any later version.
GDB is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with GDB; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "gdb.h"
/* This is broken for cross debugging. Possible solutions are:
1. Don't worry about whether the thing compiles for cross-debugging.
Go ahead and call them from i386-tdep.c.
1a. Same thing but use some macros in xm-i386.h so that gdb will
compile for cross-debugging but just give an error (or some such behavior)
when you attempt to convert floats.
2. Write a portable (in the sense of running on any machine; it would
always be for i387 floating-point formats) extended<->double converter
(which just deals with the values as arrays of char).
3. Assume the host machine has *some* IEEE chip. However, IEEE does
not standardize formats for extended floats (387 is 10 bytes, 68881 is
12 bytes), so this won't work. */
void
i387_to_double (from, to)
char *from;
char *to;
{
long *lp;
/* push extended mode on 387 stack, then pop in double mode
*
* first, set exception masks so no error is generated -
* number will be rounded to inf or 0, if necessary
*/
asm ("pushl %eax"); /* grab a stack slot */
asm ("fstcw (%esp)"); /* get 387 control word */
asm ("movl (%esp),%eax"); /* save old value */
asm ("orl $0x3f,%eax"); /* mask all exceptions */
asm ("pushl %eax");
asm ("fldcw (%esp)"); /* load new value into 387 */
asm ("movl 8(%ebp),%eax");
asm ("fldt (%eax)"); /* push extended number on 387 stack */
asm ("fwait");
asm ("movl 12(%ebp),%eax");
asm ("fstpl (%eax)"); /* pop double */
asm ("fwait");
asm ("popl %eax"); /* flush modified control word */
asm ("fnclex"); /* clear exceptions */
asm ("fldcw (%esp)"); /* restore original control word */
asm ("popl %eax"); /* flush saved copy */
}
void
double_to_i387 (from, to)
char *from;
char *to;
{
/* push double mode on 387 stack, then pop in extended mode
* no errors are possible because every 64-bit pattern
* can be converted to an extended
*/
asm ("movl 8(%ebp),%eax");
asm ("fldl (%eax)");
asm ("fwait");
asm ("movl 12(%ebp),%eax");
asm ("fstpt (%eax)");
asm ("fwait");
}
static void
print_387_control_word (control)
fp_control_t *control;
{
printf ("control 0x%04x: ", *((unsigned short *) control));
printf ("compute to ");
switch (control->pc) {
case FP_PREC_24B: printf ("24 bits; "); break;
case FP_PREC_53B: printf ("53 bits; "); break;
case FP_PREC_64B: printf ("64 bits; "); break;
default: printf ("(bad); "); break;
}
printf ("round ");
switch (control->rc) {
case FP_RND_NEAR: printf ("NEAREST; "); break;
case FP_RND_DOWN: printf ("DOWN; "); break;
case FP_RND_UP: printf ("UP; "); break;
case FP_CHOP: printf ("CHOP; "); break;
}
printf ("mask:");
if (control->invalid) printf (" INVALID");
if (control->denorm) printf (" DENORM");
if (control->zdiv) printf (" DIVZ");
if (control->ovrfl) printf (" OVERF");
if (control->undfl) printf (" UNDERF");
if (control->precis) printf (" LOS");
printf (";");
printf ("\n");
}
static void
print_387_status_word (status)
fp_status_t *status;
{
printf ("status 0x%04x: ", *((unsigned short *)status));
printf ("exceptions:");
if (status->invalid) printf (" INVALID");
if (status->denorm) printf (" DENORM");
if (status->zdiv) printf (" DIVZ");
if (status->ovrfl) printf (" OVERF");
if (status->undfl) printf (" UNDERF");
if (status->precis) printf (" LOS");
if (status->stkflt) printf (" FPSTACK");
if (status->errsumm) printf (" ERRSUMM");
printf ("; ");
printf ("flags: %d%d%d%d; ",
status->c0, status->c1, status->c2, status->c3);
printf ("top %d\n", status->tos);
}
static void
print_387_status (fp)
i386_thread_fpstate_t *fp;
{
int i;
int top;
int fpreg;
unsigned short tag;
unsigned char *p;
print_387_status_word (&fp->environ.status);
print_387_control_word (&fp->environ.control);
printf ("last exception: ");
printf ("opcode 0x%x; ", fp->environ.opcode);
printf ("pc 0x%x:0x%x; ",
*((unsigned short *) &fp->environ.cs), fp->environ.ip);
printf ("operand 0x%x:0x%x\n",
*((unsigned short *) &fp->environ.ds), fp->environ.dp);
top = fp->environ.status.tos;
tag = *((unsigned short *) &fp->environ.tag);
printf ("regno tag msb lsb value\n");
for (fpreg = 7; fpreg >= 0; fpreg--) {
double val;
printf ("%s %d: ", fpreg == top ? "=>" : " ", fpreg);
switch ((tag >> (fpreg * 2)) & 3) {
case 0: printf ("valid "); break;
case 1: printf ("zero "); break;
case 2: printf ("trap "); break;
case 3: printf ("empty "); break;
}
p = (char *) &(fp->stack.ST[fpreg]);
for (i = 9; i >= 0; i--)
printf ("%02x", p[i]);
i387_to_double ((char *)&fp->stack.ST[fpreg], (char *)&val);
printf (" %g\n", val);
}
}
void
i386_float_info ()
{
i386_thread_fpstate_t fpstate;
unsigned int fpstate_size = i386_THREAD_FPSTATE_COUNT;
extern thread_t current_thread;
if (current_thread) {
mach_call(thread_get_state(current_thread, i386_THREAD_FPSTATE, \
(thread_state_t)&fpstate, &fpstate_size),
"thread_get_state", "i386_float_info");
print_387_status (&fpstate);
}
return;
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.