linux-stable/arch/x86/math-emu/reg_divide.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

182 lines
4.9 KiB
C

/*---------------------------------------------------------------------------+
| reg_divide.c |
| |
| Divide one FPU_REG by another and put the result in a destination FPU_REG.|
| |
| Copyright (C) 1996 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
| E-mail billm@jacobi.maths.monash.edu.au |
| |
| Return value is the tag of the answer, or-ed with FPU_Exception if |
| one was raised, or -1 on internal error. |
| |
+---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------+
| The destination may be any FPU_REG, including one of the source FPU_REGs. |
+---------------------------------------------------------------------------*/
#include "exception.h"
#include "reg_constant.h"
#include "fpu_emu.h"
#include "fpu_system.h"
/*
Divide one register by another and put the result into a third register.
*/
int FPU_div(int flags, int rm, int control_w)
{
FPU_REG x, y;
FPU_REG const *a, *b, *st0_ptr, *st_ptr;
FPU_REG *dest;
u_char taga, tagb, signa, signb, sign, saved_sign;
int tag, deststnr;
if (flags & DEST_RM)
deststnr = rm;
else
deststnr = 0;
if (flags & REV) {
b = &st(0);
st0_ptr = b;
tagb = FPU_gettag0();
if (flags & LOADED) {
a = (FPU_REG *) rm;
taga = flags & 0x0f;
} else {
a = &st(rm);
st_ptr = a;
taga = FPU_gettagi(rm);
}
} else {
a = &st(0);
st0_ptr = a;
taga = FPU_gettag0();
if (flags & LOADED) {
b = (FPU_REG *) rm;
tagb = flags & 0x0f;
} else {
b = &st(rm);
st_ptr = b;
tagb = FPU_gettagi(rm);
}
}
signa = getsign(a);
signb = getsign(b);
sign = signa ^ signb;
dest = &st(deststnr);
saved_sign = getsign(dest);
if (!(taga | tagb)) {
/* Both regs Valid, this should be the most common case. */
reg_copy(a, &x);
reg_copy(b, &y);
setpositive(&x);
setpositive(&y);
tag = FPU_u_div(&x, &y, dest, control_w, sign);
if (tag < 0)
return tag;
FPU_settagi(deststnr, tag);
return tag;
}
if (taga == TAG_Special)
taga = FPU_Special(a);
if (tagb == TAG_Special)
tagb = FPU_Special(b);
if (((taga == TAG_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
|| ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
if (denormal_operand() < 0)
return FPU_Exception;
FPU_to_exp16(a, &x);
FPU_to_exp16(b, &y);
tag = FPU_u_div(&x, &y, dest, control_w, sign);
if (tag < 0)
return tag;
FPU_settagi(deststnr, tag);
return tag;
} else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) {
if (tagb != TAG_Zero) {
/* Want to find Zero/Valid */
if (tagb == TW_Denormal) {
if (denormal_operand() < 0)
return FPU_Exception;
}
/* The result is zero. */
FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
setsign(dest, sign);
return TAG_Zero;
}
/* We have an exception condition, either 0/0 or Valid/Zero. */
if (taga == TAG_Zero) {
/* 0/0 */
return arith_invalid(deststnr);
}
/* Valid/Zero */
return FPU_divide_by_zero(deststnr, sign);
}
/* Must have infinities, NaNs, etc */
else if ((taga == TW_NaN) || (tagb == TW_NaN)) {
if (flags & LOADED)
return real_2op_NaN((FPU_REG *) rm, flags & 0x0f, 0,
st0_ptr);
if (flags & DEST_RM) {
int tag;
tag = FPU_gettag0();
if (tag == TAG_Special)
tag = FPU_Special(st0_ptr);
return real_2op_NaN(st0_ptr, tag, rm,
(flags & REV) ? st0_ptr : &st(rm));
} else {
int tag;
tag = FPU_gettagi(rm);
if (tag == TAG_Special)
tag = FPU_Special(&st(rm));
return real_2op_NaN(&st(rm), tag, 0,
(flags & REV) ? st0_ptr : &st(rm));
}
} else if (taga == TW_Infinity) {
if (tagb == TW_Infinity) {
/* infinity/infinity */
return arith_invalid(deststnr);
} else {
/* tagb must be Valid or Zero */
if ((tagb == TW_Denormal) && (denormal_operand() < 0))
return FPU_Exception;
/* Infinity divided by Zero or Valid does
not raise and exception, but returns Infinity */
FPU_copy_to_regi(a, TAG_Special, deststnr);
setsign(dest, sign);
return taga;
}
} else if (tagb == TW_Infinity) {
if ((taga == TW_Denormal) && (denormal_operand() < 0))
return FPU_Exception;
/* The result is zero. */
FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
setsign(dest, sign);
return TAG_Zero;
}
#ifdef PARANOID
else {
EXCEPTION(EX_INTERNAL | 0x102);
return FPU_Exception;
}
#endif /* PARANOID */
return 0;
}