glibc/sysdeps/i386/fpu/e_atan2.S

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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
#include <machine/asm.h>
RCSID("$NetBSD: e_atan2.S,v 1.4 1995/05/08 23:46:28 jtc Exp $")
Fix atan / atan2 missing underflows (bug 15319). This patch fixes bug 15319, missing underflows from atan / atan2 when the result of atan is very close to its small argument (or that of atan2 is very close to the ratio of its arguments, which may be an exact division). The usual approach of doing an underflowing computation if the computed result is subnormal is followed. For 32-bit x86, there are extra complications: the inline __ieee754_atan2 in bits/mathinline.h needs to be disabled for float and double because other libm functions using it generally rely on getting proper underflow exceptions from it, while the out-of-line functions have to remove excess range and precision from the underflowing result so as to return an exact 0 in the case where errno should be set for underflow to 0. (The failures I saw without that are similar to those Carlos reported for other functions, where I haven't seen a response to <https://sourceware.org/ml/libc-alpha/2015-01/msg00485.html> confirming if my diagnosis is correct. Arguably all libm functions with float and double returns should remove excess range and precision, but that's a separate matter.) The x86_64 long double case reported in a comment in bug 15319 is not a bug (it's an argument of LDBL_MIN, and x86_64 is an after-rounding architecture so the correct IEEE result is not to raise underflow in the given rounding mode, in addition to treating the result as an exact LDBL_MIN being within the newly clarified documentation of accuracy goals). I'm presuming that the fpatan instruction can be trusted to raise appropriate exceptions when the (long double) result underflows (after rounding) and so no changes are needed for x86 / x86_64 long double functions here; empirically this is the case for the cases covered in the testsuite, on my system. Tested for x86_64, x86, powerpc and mips64. Only 32-bit x86 needs ulps updates (for the changes to inlines meaning some functions no longer get excess precision from their __ieee754_atan2* calls). [BZ #15319] * sysdeps/i386/fpu/e_atan2.S (dbl_min): New object. (MO): New macro. (__ieee754_atan2): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/e_atan2f.S (flt_min): New object. (MO): New macro. (__ieee754_atan2f): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/s_atan.S (dbl_min): New object. (MO): New macro. (__atan): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/s_atanf.S (flt_min): New object. (MO): New macro. (__atanf): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/ieee754/dbl-64/e_atan2.c: Include <float.h> and <math.h>. (__ieee754_atan2): Force underflow exception for results with small absolute value. * sysdeps/ieee754/dbl-64/s_atan.c: Include <float.h> and <math_private.h>. (atan): Force underflow exception for results with small absolute value. * sysdeps/ieee754/flt-32/s_atanf.c: Include <float.h>. (__atanf): Force underflow exception for results with small absolute value. * sysdeps/ieee754/ldbl-128/s_atanl.c: Include <float.h> and <math.h>. (__atanl): Force underflow exception for results with small absolute value. * sysdeps/ieee754/ldbl-128ibm/s_atanl.c: Include <float.h>. (__atanl): Force underflow exception for results with small absolute value. * sysdeps/x86/fpu/bits/mathinline.h [!__SSE2_MATH__ && !__x86_64__ && __LIBC_INTERNAL_MATH_INLINES] (__ieee754_atan2): Only define inline for long double. * sysdeps/x86_64/fpu/multiarch/e_atan2.c [HAVE_FMA4_SUPPORT || HAVE_AVX_SUPPORT]: Include <math.h>. * math/auto-libm-test-in: Do not mark underflow exceptions as possibly missing for bug 15319. Add more tests of atan2. * math/auto-libm-test-out: Regenerated. * math/libm-test.inc (casin_test_data): Do not mark underflow exceptions as possibly missing for bug 15319. (casinh_test_data): Likewise. * sysdeps/i386/fpu/libm-test-ulps: Update.
2015-02-18 21:10:49 +00:00
.section .rodata.cst8,"aM",@progbits,8
.p2align 3
.type dbl_min,@object
dbl_min: .byte 0, 0, 0, 0, 0, 0, 0x10, 0
ASM_SIZE_DIRECTIVE(dbl_min)
#ifdef PIC
# define MO(op) op##@GOTOFF(%ecx)
#else
# define MO(op) op
#endif
.text
ENTRY(__ieee754_atan2)
Fix atan / atan2 missing underflows (bug 15319). This patch fixes bug 15319, missing underflows from atan / atan2 when the result of atan is very close to its small argument (or that of atan2 is very close to the ratio of its arguments, which may be an exact division). The usual approach of doing an underflowing computation if the computed result is subnormal is followed. For 32-bit x86, there are extra complications: the inline __ieee754_atan2 in bits/mathinline.h needs to be disabled for float and double because other libm functions using it generally rely on getting proper underflow exceptions from it, while the out-of-line functions have to remove excess range and precision from the underflowing result so as to return an exact 0 in the case where errno should be set for underflow to 0. (The failures I saw without that are similar to those Carlos reported for other functions, where I haven't seen a response to <https://sourceware.org/ml/libc-alpha/2015-01/msg00485.html> confirming if my diagnosis is correct. Arguably all libm functions with float and double returns should remove excess range and precision, but that's a separate matter.) The x86_64 long double case reported in a comment in bug 15319 is not a bug (it's an argument of LDBL_MIN, and x86_64 is an after-rounding architecture so the correct IEEE result is not to raise underflow in the given rounding mode, in addition to treating the result as an exact LDBL_MIN being within the newly clarified documentation of accuracy goals). I'm presuming that the fpatan instruction can be trusted to raise appropriate exceptions when the (long double) result underflows (after rounding) and so no changes are needed for x86 / x86_64 long double functions here; empirically this is the case for the cases covered in the testsuite, on my system. Tested for x86_64, x86, powerpc and mips64. Only 32-bit x86 needs ulps updates (for the changes to inlines meaning some functions no longer get excess precision from their __ieee754_atan2* calls). [BZ #15319] * sysdeps/i386/fpu/e_atan2.S (dbl_min): New object. (MO): New macro. (__ieee754_atan2): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/e_atan2f.S (flt_min): New object. (MO): New macro. (__ieee754_atan2f): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/s_atan.S (dbl_min): New object. (MO): New macro. (__atan): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/s_atanf.S (flt_min): New object. (MO): New macro. (__atanf): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/ieee754/dbl-64/e_atan2.c: Include <float.h> and <math.h>. (__ieee754_atan2): Force underflow exception for results with small absolute value. * sysdeps/ieee754/dbl-64/s_atan.c: Include <float.h> and <math_private.h>. (atan): Force underflow exception for results with small absolute value. * sysdeps/ieee754/flt-32/s_atanf.c: Include <float.h>. (__atanf): Force underflow exception for results with small absolute value. * sysdeps/ieee754/ldbl-128/s_atanl.c: Include <float.h> and <math.h>. (__atanl): Force underflow exception for results with small absolute value. * sysdeps/ieee754/ldbl-128ibm/s_atanl.c: Include <float.h>. (__atanl): Force underflow exception for results with small absolute value. * sysdeps/x86/fpu/bits/mathinline.h [!__SSE2_MATH__ && !__x86_64__ && __LIBC_INTERNAL_MATH_INLINES] (__ieee754_atan2): Only define inline for long double. * sysdeps/x86_64/fpu/multiarch/e_atan2.c [HAVE_FMA4_SUPPORT || HAVE_AVX_SUPPORT]: Include <math.h>. * math/auto-libm-test-in: Do not mark underflow exceptions as possibly missing for bug 15319. Add more tests of atan2. * math/auto-libm-test-out: Regenerated. * math/libm-test.inc (casin_test_data): Do not mark underflow exceptions as possibly missing for bug 15319. (casinh_test_data): Likewise. * sysdeps/i386/fpu/libm-test-ulps: Update.
2015-02-18 21:10:49 +00:00
#ifdef PIC
LOAD_PIC_REG (cx)
#endif
fldl 4(%esp)
fldl 12(%esp)
fpatan
Fix atan / atan2 missing underflows (bug 15319). This patch fixes bug 15319, missing underflows from atan / atan2 when the result of atan is very close to its small argument (or that of atan2 is very close to the ratio of its arguments, which may be an exact division). The usual approach of doing an underflowing computation if the computed result is subnormal is followed. For 32-bit x86, there are extra complications: the inline __ieee754_atan2 in bits/mathinline.h needs to be disabled for float and double because other libm functions using it generally rely on getting proper underflow exceptions from it, while the out-of-line functions have to remove excess range and precision from the underflowing result so as to return an exact 0 in the case where errno should be set for underflow to 0. (The failures I saw without that are similar to those Carlos reported for other functions, where I haven't seen a response to <https://sourceware.org/ml/libc-alpha/2015-01/msg00485.html> confirming if my diagnosis is correct. Arguably all libm functions with float and double returns should remove excess range and precision, but that's a separate matter.) The x86_64 long double case reported in a comment in bug 15319 is not a bug (it's an argument of LDBL_MIN, and x86_64 is an after-rounding architecture so the correct IEEE result is not to raise underflow in the given rounding mode, in addition to treating the result as an exact LDBL_MIN being within the newly clarified documentation of accuracy goals). I'm presuming that the fpatan instruction can be trusted to raise appropriate exceptions when the (long double) result underflows (after rounding) and so no changes are needed for x86 / x86_64 long double functions here; empirically this is the case for the cases covered in the testsuite, on my system. Tested for x86_64, x86, powerpc and mips64. Only 32-bit x86 needs ulps updates (for the changes to inlines meaning some functions no longer get excess precision from their __ieee754_atan2* calls). [BZ #15319] * sysdeps/i386/fpu/e_atan2.S (dbl_min): New object. (MO): New macro. (__ieee754_atan2): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/e_atan2f.S (flt_min): New object. (MO): New macro. (__ieee754_atan2f): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/s_atan.S (dbl_min): New object. (MO): New macro. (__atan): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/i386/fpu/s_atanf.S (flt_min): New object. (MO): New macro. (__atanf): For results with small absolute value, force underflow exception and remove excess range and precision from return value. * sysdeps/ieee754/dbl-64/e_atan2.c: Include <float.h> and <math.h>. (__ieee754_atan2): Force underflow exception for results with small absolute value. * sysdeps/ieee754/dbl-64/s_atan.c: Include <float.h> and <math_private.h>. (atan): Force underflow exception for results with small absolute value. * sysdeps/ieee754/flt-32/s_atanf.c: Include <float.h>. (__atanf): Force underflow exception for results with small absolute value. * sysdeps/ieee754/ldbl-128/s_atanl.c: Include <float.h> and <math.h>. (__atanl): Force underflow exception for results with small absolute value. * sysdeps/ieee754/ldbl-128ibm/s_atanl.c: Include <float.h>. (__atanl): Force underflow exception for results with small absolute value. * sysdeps/x86/fpu/bits/mathinline.h [!__SSE2_MATH__ && !__x86_64__ && __LIBC_INTERNAL_MATH_INLINES] (__ieee754_atan2): Only define inline for long double. * sysdeps/x86_64/fpu/multiarch/e_atan2.c [HAVE_FMA4_SUPPORT || HAVE_AVX_SUPPORT]: Include <math.h>. * math/auto-libm-test-in: Do not mark underflow exceptions as possibly missing for bug 15319. Add more tests of atan2. * math/auto-libm-test-out: Regenerated. * math/libm-test.inc (casin_test_data): Do not mark underflow exceptions as possibly missing for bug 15319. (casinh_test_data): Likewise. * sysdeps/i386/fpu/libm-test-ulps: Update.
2015-02-18 21:10:49 +00:00
fldl MO(dbl_min)
fld %st(1)
fabs
fucompp
fnstsw
sahf
jnc 1f
subl $8, %esp
cfi_adjust_cfa_offset (8)
fld %st(0)
fmul %st(0)
fstpl (%esp)
fstpl (%esp)
fldl (%esp)
addl $8, %esp
cfi_adjust_cfa_offset (-8)
1: ret
update from main archive 961229 Mon Dec 30 01:32:59 1996 Ulrich Drepper <drepper@cygnus.com> * tme/localtime.c: Rewrite so that localtime_r does not call tzset, but localtime does. * features.h: Rename ANSI C to ISO C. Mention __GLIBC__ and __GLIBC_MINOR__ macros. * gnu-versions.h: Add _GNU_GETOPT_INTERFACE_VERSION. * posix/getopt.c: Use _GNU_GETOPT_INTERFACE_VERSION to check whether we can elide the code. * posix/getopt1.c: Likewise. * posix/Makefile: Correct copyright. * elf/dl-error.c (_dl_catch_error): Clear `catch' also when error occurred. * elf/dl-support.c (_dl_sysdep_open_zero_fill): Don't define if MAP_ANON is defined. * elf/eval.c: Use __getline instead of getline. * elf/rtld.c (dl_main): Check return value of _dl_new_object function for NULL. * sysdeps/generic/dl-cache.c: Update copyright. * signal/Makefile: Correct copyright. (routines): Remove gsignal and ssignal. Add bsd_signal. * signal/gsignal.c: Removed. Now is made an alias. * signal/ssignal.c: Likewise. * sysdeps/posix/raise.c: Add alias gsignal. * sysdeps/stub/raise.c: Likewise. * sysdeps/posix/signal.c: Add alias ssignal. * sysdeps/stub/signal.c: Likewise. * signal/signal.h: Declare bsd_signal. Define signal as bsd_signal if __FAVOR_BSD. * sysdeps/posix/bsd_signal.c: New file. Implementation of XPG function. * sysdeps/unix/sysv/linux/signal.c: Add explanation. * socket/sys/un.h: Define SUN_LEN according to POSIX.1g. * stdio-common/Makefile (tests): Add scanf10. * stdio-common/scanf10.c: New file. * stdio-common/vfscanf.c: Decrement counter if EOF is read while reading string. * sysdeps/libm-i387/e_acos.S: Use END, not PSEUDO_END. * sysdeps/libm-i387/e_acosl.S: Likewise. * sysdeps/libm-i387/e_asin.S: Likewise. * sysdeps/libm-i387/e_asinl.S: Likewise. * sysdeps/libm-i387/e_atan2.S: Likewise. * sysdeps/libm-i387/e_atan2f.S: Likewise. * sysdeps/libm-i387/e_atan2l.S: Likewise. * sysdeps/libm-i387/e_exp.S: Likewise. * sysdeps/libm-i387/e_expl.S: Likewise. * sysdeps/libm-i387/e_fmod.S: Likewise. * sysdeps/libm-i387/e_fmodl.S: Likewise. * sysdeps/libm-i387/e_log.S: Likewise. * sysdeps/libm-i387/e_log10.S: Likewise. * sysdeps/libm-i387/e_log10l.S: Likewise. * sysdeps/libm-i387/e_logl.S: Likewise. * sysdeps/libm-i387/e_remainder.S: Likewise. * sysdeps/libm-i387/e_remainderf.S: Likewise. * sysdeps/libm-i387/e_remainderl.S: Likewise. * sysdeps/libm-i387/e_scalb.S: Likewise. * sysdeps/libm-i387/e_scalbl.S: Likewise. * sysdeps/libm-i387/e_sqrt.S: Likewise. * sysdeps/libm-i387/e_sqrtf.S: Likewise. * sysdeps/libm-i387/e_sqrtl.S: Likewise. * sysdeps/libm-i387/s_atan.S: Likewise. * sysdeps/libm-i387/s_atanf.S: Likewise. * sysdeps/libm-i387/s_atanl.S: Likewise. * sysdeps/libm-i387/s_ceil.S: Likewise. * sysdeps/libm-i387/s_ceilf.S: Likewise. * sysdeps/libm-i387/s_ceill.S: Likewise. * sysdeps/libm-i387/s_copysign.S: Likewise. * sysdeps/libm-i387/s_copysignf.S: Likewise. * sysdeps/libm-i387/s_copysignl.S: Likewise. * sysdeps/libm-i387/s_cos.S: Likewise. * sysdeps/libm-i387/s_cosf.S: Likewise. * sysdeps/libm-i387/s_cosl.S: Likewise. * sysdeps/libm-i387/s_finite.S: Likewise. * sysdeps/libm-i387/s_finitef.S: Likewise. * sysdeps/libm-i387/s_finitel.S: Likewise. * sysdeps/libm-i387/s_floor.S: Likewise. * sysdeps/libm-i387/s_floorf.S: Likewise. * sysdeps/libm-i387/s_floorl.S: Likewise. * sysdeps/libm-i387/s_ilogb.S: Likewise. * sysdeps/libm-i387/s_ilogbf.S: Likewise. * sysdeps/libm-i387/s_ilogbl.S: Likewise. * sysdeps/libm-i387/s_log1p.S: Likewise. * sysdeps/libm-i387/s_log1pf.S: Likewise. * sysdeps/libm-i387/s_log1pl.S: Likewise. * sysdeps/libm-i387/s_logb.S: Likewise. * sysdeps/libm-i387/s_logbf.S: Likewise. * sysdeps/libm-i387/s_logbl.S: Likewise. * sysdeps/libm-i387/s_rint.S: Likewise. * sysdeps/libm-i387/s_rintf.S: Likewise. * sysdeps/libm-i387/s_rintl.S: Likewise. * sysdeps/libm-i387/s_scalbn.S: Likewise. * sysdeps/libm-i387/s_scalbnf.S: Likewise. * sysdeps/libm-i387/s_scalbnl.S: Likewise. * sysdeps/libm-i387/s_significand.S: Likewise. * sysdeps/libm-i387/s_significandf.S: Likewise. * sysdeps/libm-i387/s_significandl.S: Likewise. * sysdeps/libm-i387/s_sin.S: Likewise. * sysdeps/libm-i387/s_sinf.S: Likewise. * sysdeps/libm-i387/s_sinl.S: Likewise. * sysdeps/libm-i387/e_log.S: Use fyl2xp1 instruction for values near 1 to increase precision. * sysdeps/libm-i387/e_log10.S: Likewise. * sysdeps/libm-i387/e_log10l.S: Likewise. * sysdeps/libm-i387/e_logl.S: Likewise. * sysdeps/libm-i387/s_cos.S: Use testl instead of andw. * sysdeps/libm-i387/s_cosl.S: Likewise. * sysdeps/libm-i387/s_sin.S: Likewise. * sysdeps/libm-i387/s_sinl.S: Likewise. * sysdeps/libm-i387/s_tan.S: Likewise. * sysdeps/libm-i387/s_tanl.S: Likewise. * sysdeps/libm-i387/e_acosf.S: New file. Add float versions. * sysdeps/libm-i387/e_asinf.S: Likewise. * sysdeps/libm-i387/e_expf.S: Likewise. * sysdeps/libm-i387/e_fmodf.S: Likewise. * sysdeps/libm-i387/e_log10f.S: Likewise. * sysdeps/libm-i387/e_logf.S: Likewise. * sysdeps/libm-i387/e_scalbf.S: Likewise. * sysdeps/libm-i387/e_acosh.S: New file. Highly optimized versions. * sysdeps/libm-i387/e_acoshf.S: Likewise. * sysdeps/libm-i387/e_acoshl.S: Likewise. * sysdeps/libm-i387/e_atanh.S: Likewise. * sysdeps/libm-i387/e_atanhf.S: Likewise. * sysdeps/libm-i387/e_atanhl.S: Likewise. * sysdeps/libm-i387/e_asinh.S: Likewise. * sysdeps/libm-i387/e_asinhf.S: Likewise. * sysdeps/libm-i387/e_asinhl.S: Likewise. * sysdeps/libm-ieee754/s_asinhf.c: Tweak a bit. Use lower levels for simplified handling. * sysdeps/unix/sysv/linux/syscalls.list: Add query_module. Sun Dec 22 01:39:29 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * inet/rcmd.c (rcmd): Set h_errno before calling herror. * inet/rexec.c (rexec): Likewise. Sat Dec 21 21:47:08 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * sysdeps/unix/sysv/linux/m68k/setjmp.c (__setjmp): Make it really compatible. Sun Dec 22 03:23:33 1996 Ulrich Drepper <drepper@cygnus.com> * sysdeps/libm-i387/s_log1p.S: Use fyl2xp1 for numbers in range -0.29 <= x <= 0.29, otherwise the old method. * sysdeps/libm-i387/s_log1pf.S: Likewise. * sysdeps/libm-i387/s_log1pl.S: Likewise.
1996-12-30 01:47:46 +00:00
END (__ieee754_atan2)
strong_alias (__ieee754_atan2, __atan2_finite)