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Re: x86 FPU support: "info float" and `long double'
- To: kettenis at wins dot uva dot nl (Mark Kettenis)
- Subject: Re: x86 FPU support: "info float" and `long double'
- From: hjl at lucon dot org (H.J. Lu)
- Date: Thu, 21 Oct 1999 10:13:07 -0700 (PDT)
- Cc: gdb at sourceware dot cygnus dot com, jtc at redback dot com, jimb at cygnus dot com,eliz at gnu dot org, gdb-patches at sourceware dot cygnus dot com
> (gdb) info float
> status 0x3800: flags 0000; top 7;
> control 0x37f: 64 bit; NEAR; mask INVAL DENOR DIVZ OVERF UNDER LOS;
> last FP instruction: opcode 0xdd05; pc 0x23:0x8048495; operand 0x2b:0x8048f04
> regno tag msb lsb value
> => 7: valid 4000c90fdaa22168c000 3.141592653589793116
> 6: empty 3ff7d100000000000000 0.006378173828125
> 5: empty 40098000000000000000 1024
> 4: empty 3fff8000000000000000 1
> 3: empty 3fff8000000000000000 1
> 2: empty 3ffb9d8909ff2e48e8c0 0.076921537494659423997
> 1: empty 3ffbdaf3e93361992eb3 0.10691053569844352396
> 0: empty 00000000000000000000 0
> (gdb)
>
> Suggestions for improvement are welcome!
>
My current gdb has
(gdb) info float
st0: 0x3ffed6d6d6d6d6d6d800 Empty Normal 0.8392156862745098200307
st1: 0x00000000000000000000 Empty Zero 0
st2: 0x00000000000000000000 Empty Zero 0
st3: 0x00000000000000000000 Empty Zero 0
st4: 0x00000000000000000000 Empty Zero 0
st5: 0x3ffe8000000000000000 Empty Normal 0.5
st6: 0x4003b000000000000000 Empty Normal 22
st7: 0x4003b000000000000000 Empty Normal 22
fctrl: 0x037f 64 bit; NEAR; mask INVAL DENOR DIVZ OVERF UNDER LOS;
fstat: 0x0000 flags 0000; top 0;
ftag: 0xffff
fip: 0x00000000
fcs: 0x00000000
fopoff: 0x00000000
fopsel: 0x0000
It is also the same as yours. However, I have an extra field for stack
register:
st0: 0x3ffed6d6d6d6d6d6d800 Empty Normal 0.8392156862745098200307
^^^^^^
It shouldn't be hard to add. I am enclosing the relevant code here.
H.J.
----
expon = extract_unsigned_integer (raw_regs + REGISTER_BYTE (regnum)
+ 8, 2);
sign = expon & 0x8000;
expon &= 0x7fff;
ms = extract_unsigned_integer (raw_regs + REGISTER_BYTE (regnum) + 4, 4);
ls = extract_signed_integer (raw_regs + REGISTER_BYTE (regnum), 4);
norm = ms & 0x80000000;
if ( expon == 0 )
{
if ( ms | ls )
{
/* Denormal or Pseudodenormal. */
if ( norm )
puts_unfiltered ("Pseudo ");
else
puts_unfiltered ("Denorm ");
}
else
{
/* Zero. */
puts_unfiltered ("Zero ");
}
}
else if ( expon == 0x7fff )
{
/* Infinity, NaN or unsupported. */
if ( (ms == 0x80000000) &&
(ls == 0) )
{
puts_unfiltered ("Infty ");
}
else if ( norm )
{
if ( ms & 0x40000000 )
puts_unfiltered ("QNaN ");
else
puts_unfiltered ("SNaN ");
}
else
{
puts_unfiltered ("Unsupp ");
}
}
else
{
/* Normal or unsupported. */
if ( norm )
puts_unfiltered ("Normal ");
else
puts_unfiltered ("Unsupp ");
}