Fix pow overflow in non-default rounding modes (bug 16315).

This patch fixes bug 16315, bad pow handling of overflow/underflow in
non-default rounding modes.  Tests of pow are duly converted to
ALL_RM_TEST to run all tests in all rounding modes.

There are two main issues here.  First, various implementations
compute a negative result by negating a positive result, but this
yields inappropriate overflow / underflow values for directed
rounding, so either overflow / underflow results need recomputing in
the correct sign, or the relevant overflowing / underflowing operation
needs to be made to have a result of the correct sign.  Second, the
dbl-64 implementation sets FE_TONEAREST internally; in the overflow /
underflow case, the result needs recomputing in the original rounding
mode.

Tested x86_64 and x86 and ulps updated accordingly.

	[BZ #16315]
	* sysdeps/i386/fpu/e_pow.S (__ieee754_pow): Ensure possibly
	overflowing or underflowing operations take place with sign of
	result.
	* sysdeps/i386/fpu/e_powf.S (__ieee754_powf): Likewise.
	* sysdeps/i386/fpu/e_powl.S (__ieee754_powl): Likewise.
	* sysdeps/ieee754/dbl-64/e_pow.c: Include <math.h>.
	(__ieee754_pow): Recompute overflowing and underflowing results in
	original rounding mode.
	* sysdeps/x86/fpu/powl_helper.c: Include <stdbool.h>.
	(__powl_helper): Allow negative argument X and scale negated value
	as needed.  Avoid passing value outside [-1, 1] to f2xm1.
	* sysdeps/x86_64/fpu/e_powl.S (__ieee754_powl): Ensure possibly
	overflowing or underflowing operations take place with sign of
	result.
	* sysdeps/x86_64/fpu/multiarch/e_pow.c [HAVE_FMA4_SUPPORT]:
	Include <math.h>.
	* math/auto-libm-test-in: Add more tests of pow.
	* math/auto-libm-test-out: Regenerated.
	* math/libm-test.inc (pow_test): Use ALL_RM_TEST.
	(pow_tonearest_test_data): Remove.
	(pow_test_tonearest): Likewise.
	(pow_towardzero_test_data): Likewise.
	(pow_test_towardzero): Likewise.
	(pow_downward_test_data): Likewise.
	(pow_test_downward): Likewise.
	(pow_upward_test_data): Likewise.
	(pow_test_upward): Likewise.
	(main): Don't call removed functions.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
This commit is contained in:
Joseph Myers 2014-06-23 20:12:33 +00:00
parent 5686b236cc
commit 4da6db5188
14 changed files with 2955 additions and 235 deletions

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@ -1,3 +1,37 @@
2014-06-23 Joseph Myers <joseph@codesourcery.com>
[BZ #16315]
* sysdeps/i386/fpu/e_pow.S (__ieee754_pow): Ensure possibly
overflowing or underflowing operations take place with sign of
result.
* sysdeps/i386/fpu/e_powf.S (__ieee754_powf): Likewise.
* sysdeps/i386/fpu/e_powl.S (__ieee754_powl): Likewise.
* sysdeps/ieee754/dbl-64/e_pow.c: Include <math.h>.
(__ieee754_pow): Recompute overflowing and underflowing results in
original rounding mode.
* sysdeps/x86/fpu/powl_helper.c: Include <stdbool.h>.
(__powl_helper): Allow negative argument X and scale negated value
as needed. Avoid passing value outside [-1, 1] to f2xm1.
* sysdeps/x86_64/fpu/e_powl.S (__ieee754_powl): Ensure possibly
overflowing or underflowing operations take place with sign of
result.
* sysdeps/x86_64/fpu/multiarch/e_pow.c [HAVE_FMA4_SUPPORT]:
Include <math.h>.
* math/auto-libm-test-in: Add more tests of pow.
* math/auto-libm-test-out: Regenerated.
* math/libm-test.inc (pow_test): Use ALL_RM_TEST.
(pow_tonearest_test_data): Remove.
(pow_test_tonearest): Likewise.
(pow_towardzero_test_data): Likewise.
(pow_test_towardzero): Likewise.
(pow_downward_test_data): Likewise.
(pow_test_downward): Likewise.
(pow_upward_test_data): Likewise.
(pow_test_upward): Likewise.
(main): Don't call removed functions.
* sysdeps/i386/fpu/libm-test-ulps: Update.
* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2014-06-23 Roland McGrath <roland@hack.frob.com>
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/nptl/c++-types.data:

22
NEWS
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@ -10,17 +10,17 @@ Version 2.20
* The following bugs are resolved with this release:
6804, 9894, 12994, 13347, 13651, 14308, 14770, 15119, 15132, 15347, 15514,
15698, 15804, 15894, 15946, 16002, 16064, 16095, 16198, 16284, 16348,
16349, 16357, 16362, 16447, 16516, 16532, 16545, 16564, 16574, 16599,
16600, 16609, 16610, 16611, 16613, 16619, 16623, 16629, 16632, 16634,
16639, 16642, 16648, 16649, 16670, 16674, 16677, 16680, 16681, 16683,
16689, 16695, 16701, 16706, 16707, 16712, 16713, 16714, 16724, 16731,
16739, 16740, 16743, 16754, 16758, 16759, 16760, 16770, 16786, 16789,
16791, 16796, 16799, 16800, 16815, 16823, 16824, 16831, 16838, 16849,
16854, 16876, 16877, 16878, 16882, 16885, 16888, 16890, 16912, 16915,
16916, 16917, 16922, 16927, 16928, 16932, 16943, 16958, 16965, 16966,
16967, 16977, 16978, 16984, 16990, 16996, 17009, 17022, 17031, 17042,
17048, 17058, 17062, 17069, 17075, 17079.
15698, 15804, 15894, 15946, 16002, 16064, 16095, 16198, 16284, 16315,
16348, 16349, 16357, 16362, 16447, 16516, 16532, 16545, 16564, 16574,
16599, 16600, 16609, 16610, 16611, 16613, 16619, 16623, 16629, 16632,
16634, 16639, 16642, 16648, 16649, 16670, 16674, 16677, 16680, 16681,
16683, 16689, 16695, 16701, 16706, 16707, 16712, 16713, 16714, 16724,
16731, 16739, 16740, 16743, 16754, 16758, 16759, 16760, 16770, 16786,
16789, 16791, 16796, 16799, 16800, 16815, 16823, 16824, 16831, 16838,
16849, 16854, 16876, 16877, 16878, 16882, 16885, 16888, 16890, 16912,
16915, 16916, 16917, 16922, 16927, 16928, 16932, 16943, 16958, 16965,
16966, 16967, 16977, 16978, 16984, 16990, 16996, 17009, 17022, 17031,
17042, 17048, 17058, 17062, 17069, 17075, 17079.
* Optimized strchr implementation for AArch64. Contributed by ARM Ltd.

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@ -1613,6 +1613,71 @@ pow -max 0x1.ffffffffffffffffffffffffffffp+112
pow -max 0x1.ffffffffffffffffffffffffffffp+113
pow -max max
pow -0x1p65 2
pow -0x1p65 3
pow -0x1p65 4
pow -0x1p65 5
pow -0x1p43 3
pow -0x1p43 4
pow -0x1p43 5
pow -0x1p33 4
pow -0x1p33 5
pow -0x1p26 5
pow -0x1p-65 -2
pow -0x1p-65 -3
pow -0x1p-65 -4
pow -0x1p-65 -5
pow -0x1p-43 -3
pow -0x1p-43 -4
pow -0x1p-43 -5
pow -0x1p-33 -4
pow -0x1p-33 -5
pow -0x1p-26 -5
pow -0x1p513 2
pow -0x1p513 3
pow -0x1p513 4
pow -0x1p513 5
pow -0x1p342 3
pow -0x1p342 4
pow -0x1p342 5
pow -0x1p257 4
pow -0x1p257 5
pow -0x1p205 5
pow -0x1p-513 -2
pow -0x1p-513 -3
pow -0x1p-513 -4
pow -0x1p-513 -5
pow -0x1p-342 -3
pow -0x1p-342 -4
pow -0x1p-342 -5
pow -0x1p-257 -4
pow -0x1p-257 -5
pow -0x1p-205 -5
pow -0x1p8192 2
pow -0x1p8192 3
pow -0x1p8192 4
pow -0x1p8192 5
pow -0x1p5462 3
pow -0x1p5462 4
pow -0x1p5462 5
pow -0x1p4097 4
pow -0x1p4097 5
pow -0x1p3277 5
pow -0x1p64 257
pow -0x1p-8192 -2
pow -0x1p-8192 -3
pow -0x1p-8192 -4
pow -0x1p-8192 -5
pow -0x1p-5462 -3
pow -0x1p-5462 -4
pow -0x1p-5462 -5
pow -0x1p-4097 -4
pow -0x1p-4097 -5
pow -0x1p-3277 -5
pow -0x1p-64 -257
pow -0.5 126
pow -0.5 127
pow -0.5 -126

File diff suppressed because it is too large Load Diff

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@ -8697,69 +8697,7 @@ static const struct test_ff_f_data pow_test_data[] =
static void
pow_test (void)
{
START (pow, 0);
RUN_TEST_LOOP_ff_f (pow, pow_test_data, );
END;
}
static const struct test_ff_f_data pow_tonearest_test_data[] =
{
AUTO_TESTS_ff_f (pow),
};
static void
pow_test_tonearest (void)
{
START (pow_tonearest, 0);
RUN_TEST_LOOP_ff_f (pow, pow_tonearest_test_data, FE_TONEAREST);
END;
}
static const struct test_ff_f_data pow_towardzero_test_data[] =
{
TEST_ff_f (pow, 1.0625L, 1.125L, 1.070582293028761362162622578677070098674L),
TEST_ff_f (pow, 1.5L, 1.03125L, 1.519127098714743184071644334163037684948L),
};
static void
pow_test_towardzero (void)
{
START (pow_towardzero, 0);
RUN_TEST_LOOP_ff_f (pow, pow_towardzero_test_data, FE_TOWARDZERO);
END;
}
static const struct test_ff_f_data pow_downward_test_data[] =
{
TEST_ff_f (pow, 1.0625L, 1.125L, 1.070582293028761362162622578677070098674L),
TEST_ff_f (pow, 1.5L, 1.03125L, 1.519127098714743184071644334163037684948L),
};
static void
pow_test_downward (void)
{
START (pow_downward, 0);
RUN_TEST_LOOP_ff_f (pow, pow_downward_test_data, FE_DOWNWARD);
END;
}
static const struct test_ff_f_data pow_upward_test_data[] =
{
TEST_ff_f (pow, 1.0625L, 1.125L, 1.070582293028761362162622578677070098674L),
TEST_ff_f (pow, 1.5L, 1.03125L, 1.519127098714743184071644334163037684948L),
};
static void
pow_test_upward (void)
{
START (pow_upward, 0);
RUN_TEST_LOOP_ff_f (pow, pow_upward_test_data, FE_UPWARD);
END;
ALL_RM_TEST (pow, 0, pow_test_data, RUN_TEST_LOOP_ff_f, END);
}
@ -9946,10 +9884,6 @@ main (int argc, char **argv)
fabs_test ();
hypot_test ();
pow_test ();
pow_test_tonearest ();
pow_test_towardzero ();
pow_test_downward ();
pow_test_upward ();
sqrt_test ();
/* Error and gamma functions: */

View File

@ -144,12 +144,22 @@ ENTRY(__ieee754_pow)
4: fldl MO(one) // 1 : x
fxch
/* If y is even, take the absolute value of x. Otherwise,
ensure all intermediate values that might overflow have the
sign of x. */
testb $1, %al
jnz 6f
fabs
6: shrdl $1, %edx, %eax
jnc 5f
fxch
fabs
fmul %st(1) // x : ST*x
fxch
5: fmul %st(0), %st // x*x : ST*x
5: fld %st // x : x : ST*x
fabs // |x| : x : ST*x
fmulp // |x|*x : ST*x
shrl $1, %edx
movl %eax, %ecx
orl %edx, %ecx
@ -207,27 +217,28 @@ ENTRY(__ieee754_pow)
fxch // fract(y*log2(x)) : int(y*log2(x))
f2xm1 // 2^fract(y*log2(x))-1 : int(y*log2(x))
faddl MO(one) // 2^fract(y*log2(x)) : int(y*log2(x))
fscale // 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
fstp %st(1) // 2^fract(y*log2(x))*2^int(y*log2(x))
// Before scaling, we must negate if x is negative and y is an
// odd integer.
testb $2, %dh
jz 292f
jz 291f
// x is negative. If y is an odd integer, negate the result.
fldl 20(%esp) // y : abs(result)
fld %st // y : y : abs(result)
fabs // |y| : y : abs(result)
fcompl MO(p63) // y : abs(result)
fldl 20(%esp) // y : 2^fract(y*log2(x)) : int(y*log2(x))
fld %st // y : y : 2^fract(y*log2(x)) : int(y*log2(x))
fabs // |y| : y : 2^fract(y*log2(x)) : int(y*log2(x))
fcompl MO(p63) // y : 2^fract(y*log2(x)) : int(y*log2(x))
fnstsw
sahf
jnc 291f
jnc 290f
// We must find out whether y is an odd integer.
fld %st // y : y : abs(result)
fistpll (%esp) // y : abs(result)
fildll (%esp) // int(y) : y : abs(result)
fucompp // abs(result)
fld %st // y : y : 2^fract(y*log2(x)) : int(y*log2(x))
fistpll (%esp) // y : 2^fract(y*log2(x)) : int(y*log2(x))
fildll (%esp) // int(y) : y : 2^fract(y*log2(x)) : int(y*log2(x))
fucompp // 2^fract(y*log2(x)) : int(y*log2(x))
fnstsw
sahf
jne 292f
jne 291f
// OK, the value is an integer, but is it odd?
popl %eax
@ -235,14 +246,17 @@ ENTRY(__ieee754_pow)
popl %edx
cfi_adjust_cfa_offset (-4)
andb $1, %al
jz 290f // jump if not odd
jz 292f // jump if not odd
// It's an odd integer.
fchs
290: ret
jmp 292f
cfi_adjust_cfa_offset (8)
291: fstp %st(0) // abs(result)
292: addl $8, %esp
290: fstp %st(0) // 2^fract(y*log2(x)) : int(y*log2(x))
291: addl $8, %esp
cfi_adjust_cfa_offset (-8)
292: fscale // +/- 2^fract(y*log2(x))*2^int(y*log2(x)) : int(y*log2(x))
fstp %st(1) // +/- 2^fract(y*log2(x))*2^int(y*log2(x))
ret

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@ -129,12 +129,22 @@ ENTRY(__ieee754_powf)
4: fldl MO(one) // 1 : x
fxch
/* If y is even, take the absolute value of x. Otherwise,
ensure all intermediate values that might overflow have the
sign of x. */
testb $1, %dl
jnz 6f
fabs
6: shrl $1, %edx
jnc 5f
fxch
fabs
fmul %st(1) // x : ST*x
fxch
5: fmul %st(0), %st // x*x : ST*x
5: fld %st // x : x : ST*x
fabs // |x| : x : ST*x
fmulp // |x|*x : ST*x
testl %edx, %edx
jnz 6b
fstp %st(0) // ST*x

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@ -151,7 +151,7 @@ ENTRY(__ieee754_powl)
fcompl MO(p3) // y : x
fnstsw
sahf
jnc 2f
jnc 3f
popl %eax
cfi_adjust_cfa_offset (-4)
popl %edx
@ -166,12 +166,22 @@ ENTRY(__ieee754_powl)
4: fldl MO(one) // 1 : x
fxch
/* If y is even, take the absolute value of x. Otherwise,
ensure all intermediate values that might overflow have the
sign of x. */
testb $1, %al
jnz 6f
fabs
6: shrdl $1, %edx, %eax
jnc 5f
fxch
fabs
fmul %st(1) // x : ST*x
fxch
5: fmul %st(0), %st // x*x : ST*x
5: fld %st // x : x : ST*x
fabs // |x| : x : ST*x
fmulp // |x|*x : ST*x
shrl $1, %edx
movl %eax, %ecx
orl %edx, %ecx
@ -198,79 +208,31 @@ ENTRY(__ieee754_powl)
cfi_adjust_cfa_offset (8)
.align ALIGNARG(4)
2: // y is a large integer (absolute value at least 8), but
// may be odd unless at least 1L<<64. So it may be necessary
// to adjust the sign of a negative result afterwards.
fxch // x : y
fabs // |x| : y
fxch // y : |x|
2: // y is a large integer (absolute value at least 1L<<63).
// If y has absolute value at least 1L<<78, then any finite
// nonzero x will result in 0 (underflow), 1 or infinity (overflow).
// Saturate y to those bounds to avoid overflow in the calculation
// of y*log2(x).
fld %st // y : y : |x|
fabs // |y| : y : |x|
fcompl MO(p78) // y : |x|
fld %st // y : y : x
fabs // |y| : y : x
fcompl MO(p78) // y : x
fnstsw
sahf
jc 3f
fstp %st(0) // pop y
fldl MO(p78) // 1L<<78 : |x|
fldl MO(p78) // 1L<<78 : x
testb $2, %dl
jz 3f // y > 0
fchs // -(1L<<78) : |x|
fchs // -(1L<<78) : x
.align ALIGNARG(4)
3: /* y is a real number. */
subl $28, %esp
cfi_adjust_cfa_offset (28)
fstpt 12(%esp) // x
fstpt (%esp) // <empty>
mov %edx, 24(%esp)
call HIDDEN_JUMPTARGET (__powl_helper) // <result>
mov 24(%esp), %edx
addl $28, %esp
cfi_adjust_cfa_offset (-28)
testb $2, %dh
jz 292f
// x is negative. If y is an odd integer, negate the result.
#ifdef PIC
LOAD_PIC_REG (cx)
#endif
fldt 24(%esp) // y : abs(result)
fld %st // y : y : abs(result)
fabs // |y| : y : abs(result)
fcompl MO(p64) // y : abs(result)
fnstsw
sahf
jnc 291f
fldl MO(p63) // p63 : y : abs(result)
fxch // y : p63 : abs(result)
fprem // y%p63 : p63 : abs(result)
fstp %st(1) // y%p63 : abs(result)
// We must find out whether y is an odd integer.
fld %st // y : y : abs(result)
fistpll (%esp) // y : abs(result)
fildll (%esp) // int(y) : y : abs(result)
fucompp // abs(result)
fnstsw
sahf
jne 292f
// OK, the value is an integer, but is it odd?
popl %eax
cfi_adjust_cfa_offset (-4)
popl %edx
cfi_adjust_cfa_offset (-4)
andb $1, %al
jz 290f // jump if not odd
// It's an odd integer.
fchs
290: ret
cfi_adjust_cfa_offset (8)
291: fstp %st(0) // abs(result)
292: addl $8, %esp
cfi_adjust_cfa_offset (-8)
addl $36, %esp
cfi_adjust_cfa_offset (-36)
ret
// pow(x,±0) = 1

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@ -1653,6 +1653,8 @@ double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 4
ldouble: 4
Function: "pow_tonearest":
ildouble: 1
@ -1663,14 +1665,16 @@ double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 1
ldouble: 1
Function: "pow_upward":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 1
ldouble: 1
ildouble: 2
ldouble: 2
Function: "sin":
ildouble: 1

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@ -34,6 +34,7 @@
/* round to nearest mode of IEEE 754 standard. */
/* */
/***************************************************************************/
#include <math.h>
#include "endian.h"
#include "upow.h"
#include <dla.h>
@ -91,27 +92,33 @@ __ieee754_pow (double x, double y)
{ /* if y<-1 or y>1 */
double retval;
SET_RESTORE_ROUND (FE_TONEAREST);
{
SET_RESTORE_ROUND (FE_TONEAREST);
/* Avoid internal underflow for tiny y. The exact value of y does
not matter if |y| <= 2**-64. */
if (ABS (y) < 0x1p-64)
y = y < 0 ? -0x1p-64 : 0x1p-64;
z = log1 (x, &aa, &error); /* x^y =e^(y log (X)) */
t = y * CN;
y1 = t - (t - y);
y2 = y - y1;
t = z * CN;
a1 = t - (t - z);
a2 = (z - a1) + aa;
a = y1 * a1;
aa = y2 * a1 + y * a2;
a1 = a + aa;
a2 = (a - a1) + aa;
error = error * ABS (y);
t = __exp1 (a1, a2, 1.9e16 * error); /* return -10 or 0 if wasn't computed exactly */
retval = (t > 0) ? t : power1 (x, y);
/* Avoid internal underflow for tiny y. The exact value of y does
not matter if |y| <= 2**-64. */
if (ABS (y) < 0x1p-64)
y = y < 0 ? -0x1p-64 : 0x1p-64;
z = log1 (x, &aa, &error); /* x^y =e^(y log (X)) */
t = y * CN;
y1 = t - (t - y);
y2 = y - y1;
t = z * CN;
a1 = t - (t - z);
a2 = (z - a1) + aa;
a = y1 * a1;
aa = y2 * a1 + y * a2;
a1 = a + aa;
a2 = (a - a1) + aa;
error = error * ABS (y);
t = __exp1 (a1, a2, 1.9e16 * error); /* return -10 or 0 if wasn't computed exactly */
retval = (t > 0) ? t : power1 (x, y);
}
if (__isinf (retval))
retval = huge * huge;
else if (retval == 0)
retval = tiny * tiny;
return retval;
}
@ -164,7 +171,21 @@ __ieee754_pow (double x, double y)
return y < 0 ? 0.0 : INF.x;
}
/* if y even or odd */
return (k == 1) ? __ieee754_pow (-x, y) : -__ieee754_pow (-x, y);
if (k == 1)
return __ieee754_pow (-x, y);
else
{
double retval;
{
SET_RESTORE_ROUND (FE_TONEAREST);
retval = -__ieee754_pow (-x, y);
}
if (__isinf (retval))
retval = -huge * huge;
else if (retval == 0)
retval = -tiny * tiny;
return retval;
}
}
/* x>0 */

View File

@ -18,6 +18,7 @@
#include <math.h>
#include <math_private.h>
#include <stdbool.h>
/* High parts and low parts of -log (k/16), for integer k from 12 to
24. */
@ -63,15 +64,32 @@ acc_split (long double *rhi, long double *rlo, long double hi, long double lo,
extern long double __powl_helper (long double x, long double y);
libm_hidden_proto (__powl_helper)
/* Given X a value that is finite and nonzero, or a NaN, and only
negative if Y is not an integer, and Y a finite nonzero value with
0x1p-79 <= |Y| <= 0x1p78, compute X to the power Y. */
/* Given X a value that is finite and nonzero, or a NaN, and Y a
finite nonzero value with 0x1p-79 <= |Y| <= 0x1p78, compute X to
the power Y. */
long double
__powl_helper (long double x, long double y)
{
if (isnan (x) || x < 0)
if (isnan (x))
return __ieee754_expl (y * __ieee754_logl (x));
bool negate;
if (x < 0)
{
long double absy = fabsl (y);
if (absy >= 0x1p64L)
negate = false;
else
{
unsigned long long yll = absy;
if (yll != absy)
return __ieee754_expl (y * __ieee754_logl (x));
negate = (yll & 1) != 0;
}
x = fabsl (x);
}
else
negate = false;
/* We need to compute Y * log2 (X) to at least 64 bits after the
point for normal results (that is, to at least 78 bits
@ -199,11 +217,17 @@ __powl_helper (long double x, long double y)
fractional parts. */
long double log2_res_int = __roundl (log2_res_hi);
long double log2_res_frac = log2_res_hi - log2_res_int + log2_res_lo;
/* If the integer part is very large, the computed fractional part
may be outside the valid range for f2xm1. */
if (fabsl (log2_res_int) > 16500)
log2_res_frac = 0;
/* Compute the final result. */
long double res;
asm ("f2xm1" : "=t" (res) : "0" (log2_res_frac));
res += 1.0L;
if (negate)
res = -res;
asm ("fscale" : "=t" (res) : "0" (res), "u" (log2_res_int));
return res;
}

View File

@ -141,7 +141,7 @@ ENTRY(__ieee754_powl)
fabs // |y| : 8 : y : x
fcomip %st(1), %st // 8 : y : x
fstp %st(0) // y : x
jnc 2f
jnc 3f
mov -8(%rsp),%eax
mov -4(%rsp),%edx
orl $0, %edx
@ -154,12 +154,22 @@ ENTRY(__ieee754_powl)
4: fldl MO(one) // 1 : x
fxch
/* If y is even, take the absolute value of x. Otherwise,
ensure all intermediate values that might overflow have the
sign of x. */
testb $1, %al
jnz 6f
fabs
6: shrdl $1, %edx, %eax
jnc 5f
fxch
fabs
fmul %st(1) // x : ST*x
fxch
5: fmul %st(0), %st // x*x : ST*x
5: fld %st // x : x : ST*x
fabs // |x| : x : ST*x
fmulp // |x|*x : ST*x
shrl $1, %edx
movl %eax, %ecx
orl %edx, %ecx
@ -177,71 +187,32 @@ ENTRY(__ieee754_powl)
ret
.align ALIGNARG(4)
2: // y is a large integer (absolute value at least 8), but
// may be odd unless at least 1L<<64. So it may be necessary
// to adjust the sign of a negative result afterwards.
fxch // x : y
fabs // |x| : y
fxch // y : |x|
2: // y is a large integer (absolute value at least 1L<<63).
// If y has absolute value at least 1L<<78, then any finite
// nonzero x will result in 0 (underflow), 1 or infinity (overflow).
// Saturate y to those bounds to avoid overflow in the calculation
// of y*log2(x).
fldl MO(p78) // 1L<<78 : y : |x|
fld %st(1) // y : 1L<<78 : y : |x|
fabs // |y| : 1L<<78 : y : |x|
fcomip %st(1), %st // 1L<<78 : y : |x|
fstp %st(0) // y : |x|
fldl MO(p78) // 1L<<78 : y : x
fld %st(1) // y : 1L<<78 : y : x
fabs // |y| : 1L<<78 : y : x
fcomip %st(1), %st // 1L<<78 : y : x
fstp %st(0) // y : x
jc 3f
fstp %st(0) // pop y
fldl MO(p78) // 1L<<78 : |x|
fldl MO(p78) // 1L<<78 : x
testb $2, %dl
jz 3f // y > 0
fchs // -(1L<<78) : |x|
fchs // -(1L<<78) : x
.align ALIGNARG(4)
3: /* y is a real number. */
subq $40, %rsp
cfi_adjust_cfa_offset (40)
fstpt 16(%rsp) // x
fstpt (%rsp) // <empty>
mov %edx, 32(%rsp)
call HIDDEN_JUMPTARGET (__powl_helper) // <result>
mov 32(%rsp), %edx
addq $40, %rsp
cfi_adjust_cfa_offset (-40)
testb $2, %dh
jz 292f
// x is negative. If y is an odd integer, negate the result.
fldt 24(%rsp) // y : abs(result)
fldl MO(p64) // 1L<<64 : y : abs(result)
fld %st(1) // y : 1L<<64 : y : abs(result)
fabs // |y| : 1L<<64 : y : abs(result)
fcomip %st(1), %st // 1L<<64 : y : abs(result)
fstp %st(0) // y : abs(result)
jnc 291f
fldl MO(p63) // p63 : y : abs(result)
fxch // y : p63 : abs(result)
fprem // y%p63 : p63 : abs(result)
fstp %st(1) // y%p63 : abs(result)
// We must find out whether y is an odd integer.
fld %st // y : y : abs(result)
fistpll -8(%rsp) // y : abs(result)
fildll -8(%rsp) // int(y) : y : abs(result)
fucomip %st(1),%st // y : abs(result)
ffreep %st // abs(result)
jne 292f
// OK, the value is an integer, but is it odd?
mov -8(%rsp), %eax
mov -4(%rsp), %edx
andb $1, %al
jz 290f // jump if not odd
// It's an odd integer.
fchs
290: ret
291: fstp %st(0) // abs(result)
292: ret
ret
// pow(x,±0) = 1
.align ALIGNARG(4)

View File

@ -1736,8 +1736,12 @@ ildouble: 1
ldouble: 1
Function: "pow_downward":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 4
ldouble: 4
Function: "pow_tonearest":
float: 1
@ -1746,15 +1750,21 @@ ildouble: 1
ldouble: 1
Function: "pow_towardzero":
double: 1
float: 1
ifloat: 1
Function: "pow_upward":
float: 1
idouble: 1
ifloat: 1
ildouble: 1
ldouble: 1
Function: "pow_upward":
double: 1
float: 1
idouble: 1
ifloat: 1
ildouble: 2
ldouble: 2
Function: "sin":
ildouble: 1
ldouble: 1

View File

@ -1,5 +1,6 @@
#ifdef HAVE_FMA4_SUPPORT
# include <init-arch.h>
# include <math.h>
# include <math_private.h>
extern double __ieee754_pow_sse2 (double, double);