linux/arch/x86/math-emu/reg_compare.c
Ingo Molnar 3d0d14f983 x86: lindent arch/i386/math-emu
lindent these files:
                                       errors   lines of code   errors/KLOC
 arch/x86/math-emu/                      2236            9424         237.2
 arch/x86/math-emu/                       128            8706          14.7

no other changes. No code changed:

   text    data     bss     dec     hex filename
   5589802  612739 3833856 10036397         9924ad vmlinux.before
   5589802  612739 3833856 10036397         9924ad vmlinux.after

the intent of this patch is to ease the automated tracking of kernel
code quality - it's just much easier for us to maintain it if every file
in arch/x86 is supposed to be clean.

NOTE: it is a known problem of lindent that it causes some style damage
of its own, but it's a safe tool (well, except for the gcc array range
initializers extension), so we did the bulk of the changes via lindent,
and did the manual fixups in a followup patch.

the resulting math-emu code has been tested by Thomas Gleixner on a real
386 DX CPU as well, and it works fine.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:30:11 +01:00

351 lines
8.1 KiB
C

/*---------------------------------------------------------------------------+
| reg_compare.c |
| |
| Compare two floating point registers |
| |
| Copyright (C) 1992,1993,1994,1997 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
| E-mail billm@suburbia.net |
| |
| |
+---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------+
| compare() is the core FPU_REG comparison function |
+---------------------------------------------------------------------------*/
#include "fpu_system.h"
#include "exception.h"
#include "fpu_emu.h"
#include "control_w.h"
#include "status_w.h"
static int compare(FPU_REG const *b, int tagb)
{
int diff, exp0, expb;
u_char st0_tag;
FPU_REG *st0_ptr;
FPU_REG x, y;
u_char st0_sign, signb = getsign(b);
st0_ptr = &st(0);
st0_tag = FPU_gettag0();
st0_sign = getsign(st0_ptr);
if (tagb == TAG_Special)
tagb = FPU_Special(b);
if (st0_tag == TAG_Special)
st0_tag = FPU_Special(st0_ptr);
if (((st0_tag != TAG_Valid) && (st0_tag != TW_Denormal))
|| ((tagb != TAG_Valid) && (tagb != TW_Denormal))) {
if (st0_tag == TAG_Zero) {
if (tagb == TAG_Zero)
return COMP_A_eq_B;
if (tagb == TAG_Valid)
return ((signb ==
SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B);
if (tagb == TW_Denormal)
return ((signb ==
SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
| COMP_Denormal;
} else if (tagb == TAG_Zero) {
if (st0_tag == TAG_Valid)
return ((st0_sign ==
SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
if (st0_tag == TW_Denormal)
return ((st0_sign ==
SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
| COMP_Denormal;
}
if (st0_tag == TW_Infinity) {
if ((tagb == TAG_Valid) || (tagb == TAG_Zero))
return ((st0_sign ==
SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
else if (tagb == TW_Denormal)
return ((st0_sign ==
SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
| COMP_Denormal;
else if (tagb == TW_Infinity) {
/* The 80486 book says that infinities can be equal! */
return (st0_sign == signb) ? COMP_A_eq_B :
((st0_sign ==
SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
}
/* Fall through to the NaN code */
} else if (tagb == TW_Infinity) {
if ((st0_tag == TAG_Valid) || (st0_tag == TAG_Zero))
return ((signb ==
SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B);
if (st0_tag == TW_Denormal)
return ((signb ==
SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
| COMP_Denormal;
/* Fall through to the NaN code */
}
/* The only possibility now should be that one of the arguments
is a NaN */
if ((st0_tag == TW_NaN) || (tagb == TW_NaN)) {
int signalling = 0, unsupported = 0;
if (st0_tag == TW_NaN) {
signalling =
(st0_ptr->sigh & 0xc0000000) == 0x80000000;
unsupported = !((exponent(st0_ptr) == EXP_OVER)
&& (st0_ptr->
sigh & 0x80000000));
}
if (tagb == TW_NaN) {
signalling |=
(b->sigh & 0xc0000000) == 0x80000000;
unsupported |= !((exponent(b) == EXP_OVER)
&& (b->sigh & 0x80000000));
}
if (signalling || unsupported)
return COMP_No_Comp | COMP_SNaN | COMP_NaN;
else
/* Neither is a signaling NaN */
return COMP_No_Comp | COMP_NaN;
}
EXCEPTION(EX_Invalid);
}
if (st0_sign != signb) {
return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
| (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
COMP_Denormal : 0);
}
if ((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) {
FPU_to_exp16(st0_ptr, &x);
FPU_to_exp16(b, &y);
st0_ptr = &x;
b = &y;
exp0 = exponent16(st0_ptr);
expb = exponent16(b);
} else {
exp0 = exponent(st0_ptr);
expb = exponent(b);
}
#ifdef PARANOID
if (!(st0_ptr->sigh & 0x80000000))
EXCEPTION(EX_Invalid);
if (!(b->sigh & 0x80000000))
EXCEPTION(EX_Invalid);
#endif /* PARANOID */
diff = exp0 - expb;
if (diff == 0) {
diff = st0_ptr->sigh - b->sigh; /* Works only if ms bits are
identical */
if (diff == 0) {
diff = st0_ptr->sigl > b->sigl;
if (diff == 0)
diff = -(st0_ptr->sigl < b->sigl);
}
}
if (diff > 0) {
return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
| (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
COMP_Denormal : 0);
}
if (diff < 0) {
return ((st0_sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
| (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
COMP_Denormal : 0);
}
return COMP_A_eq_B
| (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
COMP_Denormal : 0);
}
/* This function requires that st(0) is not empty */
int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag)
{
int f = 0, c;
c = compare(loaded_data, loaded_tag);
if (c & COMP_NaN) {
EXCEPTION(EX_Invalid);
f = SW_C3 | SW_C2 | SW_C0;
} else
switch (c & 7) {
case COMP_A_lt_B:
f = SW_C0;
break;
case COMP_A_eq_B:
f = SW_C3;
break;
case COMP_A_gt_B:
f = 0;
break;
case COMP_No_Comp:
f = SW_C3 | SW_C2 | SW_C0;
break;
#ifdef PARANOID
default:
EXCEPTION(EX_INTERNAL | 0x121);
f = SW_C3 | SW_C2 | SW_C0;
break;
#endif /* PARANOID */
}
setcc(f);
if (c & COMP_Denormal) {
return denormal_operand() < 0;
}
return 0;
}
static int compare_st_st(int nr)
{
int f = 0, c;
FPU_REG *st_ptr;
if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
setcc(SW_C3 | SW_C2 | SW_C0);
/* Stack fault */
EXCEPTION(EX_StackUnder);
return !(control_word & CW_Invalid);
}
st_ptr = &st(nr);
c = compare(st_ptr, FPU_gettagi(nr));
if (c & COMP_NaN) {
setcc(SW_C3 | SW_C2 | SW_C0);
EXCEPTION(EX_Invalid);
return !(control_word & CW_Invalid);
} else
switch (c & 7) {
case COMP_A_lt_B:
f = SW_C0;
break;
case COMP_A_eq_B:
f = SW_C3;
break;
case COMP_A_gt_B:
f = 0;
break;
case COMP_No_Comp:
f = SW_C3 | SW_C2 | SW_C0;
break;
#ifdef PARANOID
default:
EXCEPTION(EX_INTERNAL | 0x122);
f = SW_C3 | SW_C2 | SW_C0;
break;
#endif /* PARANOID */
}
setcc(f);
if (c & COMP_Denormal) {
return denormal_operand() < 0;
}
return 0;
}
static int compare_u_st_st(int nr)
{
int f = 0, c;
FPU_REG *st_ptr;
if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
setcc(SW_C3 | SW_C2 | SW_C0);
/* Stack fault */
EXCEPTION(EX_StackUnder);
return !(control_word & CW_Invalid);
}
st_ptr = &st(nr);
c = compare(st_ptr, FPU_gettagi(nr));
if (c & COMP_NaN) {
setcc(SW_C3 | SW_C2 | SW_C0);
if (c & COMP_SNaN) { /* This is the only difference between
un-ordered and ordinary comparisons */
EXCEPTION(EX_Invalid);
return !(control_word & CW_Invalid);
}
return 0;
} else
switch (c & 7) {
case COMP_A_lt_B:
f = SW_C0;
break;
case COMP_A_eq_B:
f = SW_C3;
break;
case COMP_A_gt_B:
f = 0;
break;
case COMP_No_Comp:
f = SW_C3 | SW_C2 | SW_C0;
break;
#ifdef PARANOID
default:
EXCEPTION(EX_INTERNAL | 0x123);
f = SW_C3 | SW_C2 | SW_C0;
break;
#endif /* PARANOID */
}
setcc(f);
if (c & COMP_Denormal) {
return denormal_operand() < 0;
}
return 0;
}
/*---------------------------------------------------------------------------*/
void fcom_st(void)
{
/* fcom st(i) */
compare_st_st(FPU_rm);
}
void fcompst(void)
{
/* fcomp st(i) */
if (!compare_st_st(FPU_rm))
FPU_pop();
}
void fcompp(void)
{
/* fcompp */
if (FPU_rm != 1) {
FPU_illegal();
return;
}
if (!compare_st_st(1))
poppop();
}
void fucom_(void)
{
/* fucom st(i) */
compare_u_st_st(FPU_rm);
}
void fucomp(void)
{
/* fucomp st(i) */
if (!compare_u_st_st(FPU_rm))
FPU_pop();
}
void fucompp(void)
{
/* fucompp */
if (FPU_rm == 1) {
if (!compare_u_st_st(1))
poppop();
} else
FPU_illegal();
}