* [PATCH] Fix i386/x86_64 log{,10,2,1p}{,f,l}
@ 2007-03-15 17:15 Jakub Jelinek
0 siblings, 0 replies; only message in thread
From: Jakub Jelinek @ 2007-03-15 17:15 UTC (permalink / raw)
To: Ulrich Drepper; +Cc: Glibc hackers
Hi!
As the added tests show, we had some issues in hand written log* assembly:
1) logl(NAN) on x86_64 and log{,f,l}(NAN) on i386 raised FE_INVALID, while
it shouldn't, at least neither Domain nor Pole error is documented for
x is NaN case in
http://www.opengroup.org/onlinepubs/009695399/functions/logl.html
2) log{2,10}l(-HUGE_VALL) on x86_64 didn't raise FE_INVALID, while it
was supposed to (Domain error is documented for that the same as
it is for negative finite arguments)
3) log1pl(-HUGE_VALL) returned -HUGE_VALL instead of NAN and didn't
raise FE_INVALID on x86_64
2) and 3) were caused by broken conversion from sahf: the original
i386 code did: sahf; jc 3f; 4: ... 3: jp 4b; (wanted to execute
code after jp only for NaN (i.e. (%ah & 0x45) == 1) and code at
4: for other cases. This was converted to
andb $1, %ah; jnz 3f; 4: ... 3: jp 4b; but of course jp never
branched, because the result of andb was always 1. This can be
either done as in the patch below
(testb $1, %ah; jnz 3f; 4: ... 3: testb $4, %ah; jnz 4b;)
or perhaps could be done as shorter (but more insns in the common
case) andb $0x45, %ah; cmpb $1, %ah; jz 3f; 4: ... 3:
2007-03-15 Jakub Jelinek <jakub@redhat.com>
[BZ #3919]
* math/libm-test.inc (log_test): Test -Inf and NaN.
(log10_test, log1p_test, log2_test): Test -Inf.
* sysdeps/i386/fpu/e_log.S (__ieee754_log): Don't raise
FE_INVALID when argument is qNaN.
* sysdeps/i386/fpu/e_logl.S (__ieee754_logl): Likewise.
* sysdeps/i386/fpu/e_logf.S (__ieee754_logf): Likewise.
* sysdeps/x86_64/fpu/e_logl.S (__ieee754_logl): Likewise.
* sysdeps/x86_64/fpu/e_log10l.S (__ieee754_log10l): Replace
andb $1, %ah with testb $1, %ah, don't test for parity, instead
testb $4, %ah and jump if non-zero.
* sysdeps/x86_64/fpu/e_log2l.S (__ieee754_log2l): Likewise.
* sysdeps/x86_64/fpu/s_log1pl.S (__log1pl): Likewise.
--- libc/math/libm-test.inc.jj 2007-03-13 17:42:15.000000000 +0100
+++ libc/math/libm-test.inc 2007-03-15 16:14:28.000000000 +0100
@@ -4127,7 +4127,9 @@ log_test (void)
TEST_f_f (log, 1, 0);
TEST_f_f (log, -1, nan_value, INVALID_EXCEPTION);
+ TEST_f_f (log, minus_infty, nan_value, INVALID_EXCEPTION);
TEST_f_f (log, plus_infty, plus_infty);
+ TEST_f_f (log, nan_value, nan_value);
TEST_f_f (log, M_El, 1);
TEST_f_f (log, 1.0 / M_El, -1);
@@ -4157,6 +4159,7 @@ log10_test (void)
/* log10 (x) == NaN plus invalid exception if x < 0. */
TEST_f_f (log10, -1, nan_value, INVALID_EXCEPTION);
+ TEST_f_f (log10, minus_infty, nan_value, INVALID_EXCEPTION);
TEST_f_f (log10, plus_infty, plus_infty);
TEST_f_f (log10, nan_value, nan_value);
@@ -4188,6 +4191,7 @@ log1p_test (void)
TEST_f_f (log1p, -1, minus_infty, DIVIDE_BY_ZERO_EXCEPTION);
TEST_f_f (log1p, -2, nan_value, INVALID_EXCEPTION);
+ TEST_f_f (log1p, minus_infty, nan_value, INVALID_EXCEPTION);
TEST_f_f (log1p, plus_infty, plus_infty);
TEST_f_f (log1p, nan_value, nan_value);
@@ -4218,6 +4222,7 @@ log2_test (void)
TEST_f_f (log2, 1, 0);
TEST_f_f (log2, -1, nan_value, INVALID_EXCEPTION);
+ TEST_f_f (log2, minus_infty, nan_value, INVALID_EXCEPTION);
TEST_f_f (log2, plus_infty, plus_infty);
TEST_f_f (log2, nan_value, nan_value);
--- libc/sysdeps/i386/fpu/e_log.S.jj 2005-05-04 19:45:15.000000000 +0200
+++ libc/sysdeps/i386/fpu/e_log.S 2007-03-15 17:57:18.000000000 +0100
@@ -36,11 +36,15 @@ limit: .double 0.29
ENTRY(__ieee754_log)
fldln2 // log(2)
fldl 4(%esp) // x : log(2)
+ fxam
+ fnstsw
#ifdef PIC
LOAD_PIC_REG (dx)
#endif
fld %st // x : x : log(2)
- fsubl MO(one) // x-1 : x : log(2)
+ sahf
+ jc 3f // in case x is NaN or +-Inf
+4: fsubl MO(one) // x-1 : x : log(2)
fld %st // x-1 : x-1 : x : log(2)
fabs // |x-1| : x-1 : x : log(2)
fcompl MO(limit) // x-1 : x : log(2)
@@ -54,4 +58,9 @@ ENTRY(__ieee754_log)
2: fstp %st(0) // x : log(2)
fyl2x // log(x)
ret
+
+3: jp 4b // in case x is +-Inf
+ fstp %st(1)
+ fstp %st(1)
+ ret
END (__ieee754_log)
--- libc/sysdeps/i386/fpu/e_logf.S.jj 2005-05-04 19:45:15.000000000 +0200
+++ libc/sysdeps/i386/fpu/e_logf.S 2007-03-15 17:56:15.000000000 +0100
@@ -37,11 +37,15 @@ limit: .double 0.29
ENTRY(__ieee754_logf)
fldln2 // log(2)
flds 4(%esp) // x : log(2)
+ fxam
+ fnstsw
#ifdef PIC
LOAD_PIC_REG (dx)
#endif
fld %st // x : x : log(2)
- fsubl MO(one) // x-1 : x : log(2)
+ sahf
+ jc 3f // in case x is NaN or +-Inf
+4: fsubl MO(one) // x-1 : x : log(2)
fld %st // x-1 : x-1 : x : log(2)
fabs // |x-1| : x-1 : x : log(2)
fcompl MO(limit) // x-1 : x : log(2)
@@ -55,4 +59,9 @@ ENTRY(__ieee754_logf)
2: fstp %st(0) // x : log(2)
fyl2x // log(x)
ret
+
+3: jp 4b // in case x is +-Inf
+ fstp %st(1)
+ fstp %st(1)
+ ret
END (__ieee754_logf)
--- libc/sysdeps/i386/fpu/e_logl.S.jj 2005-05-04 19:45:15.000000000 +0200
+++ libc/sysdeps/i386/fpu/e_logl.S 2007-03-15 17:54:29.000000000 +0100
@@ -37,11 +37,15 @@ limit: .double 0.29
ENTRY(__ieee754_logl)
fldln2 // log(2)
fldt 4(%esp) // x : log(2)
+ fxam
+ fnstsw
#ifdef PIC
LOAD_PIC_REG (dx)
#endif
fld %st // x : x : log(2)
- fsubl MO(one) // x-1 : x : log(2)
+ sahf
+ jc 3f // in case x is NaN or +-Inf
+4: fsubl MO(one) // x-1 : x : log(2)
fld %st // x-1 : x-1 : x : log(2)
fabs // |x-1| : x-1 : x : log(2)
fcompl MO(limit) // x-1 : x : log(2)
@@ -55,4 +59,9 @@ ENTRY(__ieee754_logl)
2: fstp %st(0) // x : log(2)
fyl2x // log(x)
ret
+
+3: jp 4b // in case x is +-Inf
+ fstp %st(1)
+ fstp %st(1)
+ ret
END (__ieee754_logl)
--- libc/sysdeps/x86_64/fpu/s_log1pl.S.jj 2001-09-19 12:24:08.000000000 +0200
+++ libc/sysdeps/x86_64/fpu/s_log1pl.S 2007-03-15 17:47:56.000000000 +0100
@@ -45,7 +45,7 @@ ENTRY(__log1pl)
fxam
fnstsw
fld %st
- andb $1,%ah
+ testb $1, %ah
jnz 3f // in case x is NaN or ±Inf
4:
fabs
@@ -62,7 +62,8 @@ ENTRY(__log1pl)
2: fyl2xp1
ret
-3: jp 4b // in case x is ±Inf
+3: testb $4, %ah
+ jnz 4b // in case x is ±Inf
fstp %st(1)
fstp %st(1)
ret
--- libc/sysdeps/x86_64/fpu/e_log10l.S.jj 2001-09-19 12:24:08.000000000 +0200
+++ libc/sysdeps/x86_64/fpu/e_log10l.S 2007-03-15 17:46:02.000000000 +0100
@@ -42,7 +42,7 @@ ENTRY(__ieee754_log10l)
fxam
fnstsw
fld %st // x : x : log10(2)
- andb $1,%ah
+ testb $1, %ah
jnz 3f // in case x is NaN or ±Inf
4: fsubl MO(one) // x-1 : x : log10(2)
fld %st // x-1 : x-1 : x : log10(2)
@@ -59,7 +59,8 @@ ENTRY(__ieee754_log10l)
fyl2x // log10(x)
ret
-3: jp 4b // in case x is ±Inf
+3: testb $4, %ah
+ jnz 4b // in case x is ±Inf
fstp %st(1)
fstp %st(1)
ret
--- libc/sysdeps/x86_64/fpu/e_log2l.S.jj 2001-09-19 12:24:08.000000000 +0200
+++ libc/sysdeps/x86_64/fpu/e_log2l.S 2007-03-15 17:45:27.000000000 +0100
@@ -39,7 +39,7 @@ ENTRY(__ieee754_log2l)
fxam
fnstsw
fld %st // x : x : 1
- andb $1,%ah
+ testb $1, %ah
jnz 3f // in case x is NaN or ±Inf
4: fsub %st(2), %st // x-1 : x : 1
fld %st // x-1 : x-1 : x : 1
@@ -56,7 +56,8 @@ ENTRY(__ieee754_log2l)
fyl2x // log(x)
ret
-3: jp 4b // in case x is ±Inf
+3: testb $4, %ah
+ jnz 4b // in case x is ±Inf
fstp %st(1)
fstp %st(1)
ret
--- libc/sysdeps/x86_64/fpu/e_logl.S.jj 2001-09-19 12:24:08.000000000 +0200
+++ libc/sysdeps/x86_64/fpu/e_logl.S 2007-03-15 17:46:16.000000000 +0100
@@ -38,8 +38,12 @@ limit: .double 0.29
ENTRY(__ieee754_logl)
fldln2 // log(2)
fldt 8(%rsp) // x : log(2)
+ fxam
+ fnstsw
fld %st // x : x : log(2)
- fsubl MO(one) // x-1 : x : log(2)
+ testb $1, %ah
+ jnz 3f // in case x is NaN or +-Inf
+4: fsubl MO(one) // x-1 : x : log(2)
fld %st // x-1 : x-1 : x : log(2)
fabs // |x-1| : x-1 : x : log(2)
fcompl MO(limit) // x-1 : x : log(2)
@@ -53,4 +57,10 @@ ENTRY(__ieee754_logl)
2: fstp %st(0) // x : log(2)
fyl2x // log(x)
ret
+
+3: testb $4, %ah
+ jnz 4b // in case x is +-Inf
+ fstp %st(1)
+ fstp %st(1)
+ ret
END (__ieee754_logl)
Jakub
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