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arch
x86
math-emu
fpu_tags.c
Go to the documentation of this file.
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/*---------------------------------------------------------------------------+
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| fpu_tags.c |
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| |
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| Set FPU register tags. |
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| |
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| Copyright (C) 1997 |
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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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#include "
fpu_emu.h
"
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#include "
fpu_system.h
"
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#include "
exception.h
"
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void
FPU_pop
(
void
)
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{
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fpu_tag_word
|= 3 << ((
top
& 7) * 2);
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top
++;
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}
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int
FPU_gettag0
(
void
)
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{
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return
(
fpu_tag_word
>> ((
top
& 7) * 2)) & 3;
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}
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int
FPU_gettagi
(
int
stnr)
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{
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return
(
fpu_tag_word
>> (((
top
+ stnr) & 7) * 2)) & 3;
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}
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int
FPU_gettag
(
int
regnr)
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{
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return
(
fpu_tag_word
>> ((regnr & 7) * 2)) & 3;
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}
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void
FPU_settag0
(
int
tag
)
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{
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int
regnr =
top
;
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regnr &= 7;
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fpu_tag_word
&= ~(3 << (regnr * 2));
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fpu_tag_word
|= (tag & 3) << (regnr * 2);
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}
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void
FPU_settagi
(
int
stnr,
int
tag
)
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{
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int
regnr = stnr +
top
;
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regnr &= 7;
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fpu_tag_word
&= ~(3 << (regnr * 2));
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fpu_tag_word
|= (tag & 3) << (regnr * 2);
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}
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void
FPU_settag
(
int
regnr,
int
tag
)
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{
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regnr &= 7;
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fpu_tag_word
&= ~(3 << (regnr * 2));
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fpu_tag_word
|= (tag & 3) << (regnr * 2);
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}
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int
FPU_Special
(
FPU_REG
const
*
ptr
)
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{
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int
exp
=
exponent
(ptr);
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if
(exp ==
EXP_BIAS
+
EXP_UNDER
)
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return
TW_Denormal
;
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else
if
(exp !=
EXP_BIAS
+
EXP_OVER
)
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return
TW_NaN
;
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else
if
((ptr->
sigh
== 0x80000000) && (ptr->
sigl
== 0))
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return
TW_Infinity
;
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return
TW_NaN
;
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}
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int
isNaN
(
FPU_REG
const
*
ptr
)
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{
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return
((
exponent
(ptr) ==
EXP_BIAS
+
EXP_OVER
)
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&& !((ptr->
sigh
== 0x80000000) && (ptr->
sigl
== 0)));
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}
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int
FPU_empty_i
(
int
stnr)
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{
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int
regnr = (
top
+ stnr) & 7;
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return
((
fpu_tag_word
>> (regnr * 2)) & 3) ==
TAG_Empty
;
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}
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int
FPU_stackoverflow
(
FPU_REG
** st_new_ptr)
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{
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*st_new_ptr = &
st
(-1);
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return
((
fpu_tag_word
>> (((
top
- 1) & 7) * 2)) & 3) !=
TAG_Empty
;
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}
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void
FPU_copy_to_regi
(
FPU_REG
const
*
r
,
u_char
tag
,
int
stnr)
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{
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reg_copy(r, &
st
(stnr));
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FPU_settagi
(stnr, tag);
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}
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void
FPU_copy_to_reg1
(
FPU_REG
const
*
r
,
u_char
tag
)
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{
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reg_copy(r, &
st
(1));
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FPU_settagi
(1, tag);
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}
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void
FPU_copy_to_reg0
(
FPU_REG
const
*
r
,
u_char
tag
)
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{
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int
regnr =
top
;
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regnr &= 7;
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reg_copy(r, &
st
(0));
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fpu_tag_word
&= ~(3 << (regnr * 2));
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fpu_tag_word
|= (tag & 3) << (regnr * 2);
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}
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