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2013-09-05math: rewrite hypotSzabolcs Nagy3-324/+135
method: if there is a large difference between the scale of x and y then the larger magnitude dominates, otherwise reduce x,y so the argument of sqrt (x*x+y*y) does not overflow or underflow and calculate the argument precisely using exact multiplication. If the argument has less error than 1/sqrt(2) ~ 0.7 ulp, then the result has less error than 1 ulp in nearest rounding mode. the original fdlibm method was the same, except it used bit hacks instead of dekker-veltkamp algorithm, which is problematic for long double where different representations are supported. (the new hypot and hypotl code should be smaller and faster on 32bit cpu archs with fast fpu), the new code behaves differently in non-nearest rounding, but the error should be still less than 2ulps. ld80 and ld128 are supported
2013-09-05math: rewrite remainder functions (remainder, remquo, fmod, modf)Szabolcs Nagy11-1010/+472
* results are exact * modfl follows truncl (raises inexact flag spuriously now) * modf and modff only had cosmetic cleanup * remainder is just a wrapper around remquo now * using iterative shift+subtract for remquo and fmod * ld80 and ld128 are supported as well
2013-09-05math: rewrite rounding functions (ceil, floor, trunc, round, rint)Szabolcs Nagy15-905/+274
* faster, smaller, cleaner implementation than the bit hacks of fdlibm * use arithmetics like y=(double)(x+0x1p52)-0x1p52, which is an integer neighbor of x in all rounding modes (0<=x<0x1p52) and only use bithacks when that's faster and smaller (for float it usually is) * the code assumes standard excess precision handling for casts * long double code supports both ld80 and ld128 * nearbyint is not changed (it is a wrapper around rint)
2013-09-05math: fix logb(-0.0) in downward rounding modeSzabolcs Nagy3-6/+6
use -1/(x*x) instead of -1/(x+0) to return -inf, -0+0 is -0 in downward rounding mode
2013-09-05math: ilogb cleanupSzabolcs Nagy3-16/+43
* consistent code style * explicit union instead of typedef for double and float bit access * turn FENV_ACCESS ON to make 0/0.0f raise invalid flag * (untested) ld128 version of ilogbl (used by logbl which has ld128 support)
2013-09-05long double cleanup, initial commitSzabolcs Nagy8-96/+89
new ldshape union, ld128 support is kept, code that used the old ldshape union was rewritten (IEEEl2bits union of freebsd libm is not touched yet) ld80 __fpclassifyl no longer tries to handle invalid representation
2013-09-04fix typo in comment in __randnameRich Felker1-1/+1
2013-09-02fix mips-specific bug in synccall (too little space for signal mask)Rich Felker1-5/+3
switch to the new __block_all_sigs/__restore_sigs internal API to clean up the code too.
2013-09-02in synccall, ignore the signal before any threads' signal handlers returnRich Felker1-4/+4
this protects against deadlock from spurious signals (e.g. sent by another process) arriving after the controlling thread releases the other threads from the sync operation.
2013-09-02fix invalid pointer in synccall (multithread setuid, etc.)Rich Felker1-0/+1
the head pointer was not being reset between calls to synccall, so any use of this interface more than once would build the linked list incorrectly, keeping the (now invalid) list nodes from the previous call.
2013-09-01fix special-case breakage in popen due to reversed argument orderRich Felker1-1/+1
2013-08-31fix missing return value warning in faccessat, minor cleanupRich Felker1-1/+1
clone will pass the return value of the start function to SYS_exit anyway; there's no need to call the syscall directly.
2013-08-31fix invalid %m format crash in wide scanf variantsRich Felker1-0/+2
the wide variant was missed in the previous commit.
2013-08-31avoid crash in scanf when invalid %m format is encounteredRich Felker1-0/+2
invalid format strings invoke undefined behavior, so this is not a conformance issue, but it's nicer for scanf to report the error safely instead of calling free on a potentially-uninitialized pointer or a pointer to memory belonging to the caller.
2013-08-31remove incorrect cancellation points from realpathRich Felker1-4/+4
2013-08-31debloat realpath's allocation strategyRich Felker1-12/+6
rather than allocating a PATH_MAX-sized buffer when the caller does not provide an output buffer, work first with a PATH_MAX-sized temp buffer with automatic storage, and either copy it to the caller's buffer or strdup it on success. this not only avoids massive memory waste, but also avoids pulling in free (and thus the full malloc implementation) unnecessarily in static programs.
2013-08-31make realpath use O_PATH when opening the fileRich Felker1-1/+1
this avoids failure if the file is not readable and avoids odd behavior for device nodes, etc. on old kernels that lack O_PATH, the old behavior (O_RDONLY) will naturally happen as the fallback.
2013-08-31fix breakage in synccall due to incorrect signal restoration in sigqueueRich Felker1-2/+3
commit 07827d1a82fb33262f686eda959857f0d28cd8fa seems to have introduced this issue. sigqueue is called from the synccall core, at which time, even implementation-internal signals are blocked. however, pthread_sigmask removes the implementation-internal signals from the old mask before returning, so that a process which began life with them blocked will not be able to save a signal mask that has them blocked, possibly causing them to become re-blocked later. however, this was causing sigqueue to unblock the implementation-internal signals during synccall, leading to deadlock.
2013-08-28optimized C memcpyRich Felker1-16/+111
unlike the old C memcpy, this version handles word-at-a-time reads and writes even for misaligned copies. it does not require that the cpu support misaligned accesses; instead, it performs bit shifts to realign the bytes for the destination. essentially, this is the C version of the ARM assembly language memcpy. the ideas are all the same, and it should perform well on any arch with a decent number of general-purpose registers that has a barrel shift operation. since the barrel shifter is an optional cpu feature on microblaze, it may be desirable to provide an alternate asm implementation on microblaze, but otherwise the C code provides a competitive implementation for "generic risc-y" cpu archs that should alleviate the urgent need for arch-specific memcpy asm.
2013-08-27fix invalid instruction mnemonics in powerpc fenv asmRich Felker1-3/+3
there is no non-dot version of the andis instruction, but there's no harm in updating the flags anyway, so just use the dot version.
2013-08-27optimized C memsetRich Felker1-12/+77
this version of memset is optimized both for small and large values of n, and makes no misaligned writes, so it is usable (and near-optimal) on all archs. it is capable of filling up to 52 or 56 bytes without entering a loop and with at most 7 branches, all of which can be fully predicted if memset is called multiple times with the same size. it also uses the attribute extension to inform the compiler that it is violating the aliasing rules, unlike the previous code which simply assumed it was safe to violate the aliasing rules since translation unit boundaries hide the violations from the compiler. for non-GNUC compilers, 100% portable fallback code in the form of a naive loop is provided. I intend to eventually apply this approach to all of the string/memory functions which are doing word-at-a-time accesses.
2013-08-25add the %s (seconds since the epoch) format to strftimeRich Felker1-0/+4
this is a nonstandard extension but will be required in the next version of POSIX, and it's widely used/useful in shell scripts utilizing the date utility.
2013-08-24fix strftime regression in %e formatRich Felker1-2/+2
%e pads with spaces instead of zeros.
2013-08-24properly fill in tzname[] for old (pre-64-bit-format) zoneinfo filesRich Felker1-1/+22
in this case, the first standard-time and first daylight-time rules should be taken as the "default" ones to expose.
2013-08-24minor fix to tz name checkingRich Felker1-2/+2
if a zoneinfo file is not (or is no longer) in use, don't check the abbrevs pointers, which may be invalid.
2013-08-24fix strftime handling of time zone dataRich Felker4-8/+36
this may need further revision in the future, since POSIX is rather unclear on the requirements, and is designed around the assumption of POSIX TZ specifiers which are not sufficiently powerful to represent real-world timezones (this is why zoneinfo support was added). the basic issue is that strftime gets the string and numeric offset for the timezone from the extra fields in struct tm, which are initialized when calling localtime/gmtime/etc. however, a conforming application might have created its own struct tm without initializing these fields, in which case using __tm_zone (a pointer) could crash. other zoneinfo-based implementations simply check for a null pointer, but otherwise can still crash of the field contains junk. simply ignoring __tm_zone and using tzname[] would "work" but would give incorrect results in time zones with more complex rules. I feel like this would lower the quality of implementation. instead, simply validate __tm_zone: unless it points to one of the zone name strings managed by the timezone system, assume it's invalid. this commit also fixes several other minor bugs with formatting: tm_isdst being negative is required to suppress printing of the zone formats, and %z was using the wrong format specifiers since the type of val was changed, resulting in bogus output.
2013-08-23make dlopen honor the rpath of the main programRich Felker1-1/+1
this seems to match what other systems do, and seems useful for programs that have their libraries and plugins stored relative to the executable.
2013-08-23fix mishandling of empty or blank TZ environment variableRich Felker1-1/+1
the empty TZ string was matching equal to the initial value of the cached TZ name, thus causing do_tzset never to run and never to initialize the time zone data.
2013-08-23fix regression in dn_expand/reverse dnsRich Felker1-1/+1
off-by-one error copying the name components was yielding junk at the beginning and truncating one character at the end (of every component).
2013-08-23fix bugs in $ORIGIN handlingRich Felker1-3/+9
1. an occurrence of ${ORIGIN} before $ORIGIN would be ignored due to the strstr logic. (note that rpath contains multiple :-delimited paths to be searched.) 2. data read by readlink was not null-terminated.
2013-08-23use AT_EXECFN, if available, for dynamic linker to identify main programRich Felker1-1/+5
fallback to argv[0] as before. unlike argv[0], AT_EXECFN was a valid (but possibly relative) pathname for the new program image at the time the execve syscall was made. as a special case, ignore AT_EXECFN if it begins with "/proc/", in order not to give bogus (and possibly harmful) results when fexecve was used.
2013-08-23add rpath $ORIGIN processing to dynamic linkerRich Felker1-3/+59
2013-08-23add recursive rpath support to dynamic linkerRich Felker1-12/+13
previously, rpath was only honored for direct dependencies. in other words, if A depends on B and B depends on C, only B's rpath (if any), not A's rpath, was being searched for C. this limitation made rpath-based deployment difficult in the presence of multiple levels of library dependency. at present, $ORIGIN processing in rpath is still unsupported.
2013-08-23fix missing string.h in strftime.c (needed by new strftime code)Rich Felker1-0/+1
this bug was masked by local experimental CFLAGS in my config.mak.
2013-08-22add strftime and wcsftime field widthsRich Felker2-24/+81
at present, since POSIX requires %F to behave as %+4Y-%m-%d and ISO C requires %F to behave as %Y-%m-%d, the default behavior for %Y has been changed to match %+4Y. this seems to be the only way to conform to the requirements of both standards, and it does not affect years prior to the year 10000. depending on the outcome of interpretations from the standards bodies, this may be adjusted at some point.
2013-08-22simplify strftime and fix integer overflowsRich Felker1-28/+12
use a long long value so that even with offsets, values cannot overflow. instead of using different format strings for different numeric formats, simply use a per-format width and %0*lld for all of them. this width specifier is not for use with strftime field widths; that will be a separate step in the caller.
2013-08-22strftime cleanup: avoid recomputing strlen when it's knownRich Felker1-10/+16
2013-08-22more strftime refactoringRich Felker1-23/+25
make __strftime_fmt_1 return a string (possibly in the caller-provided temp buffer) rather than writing into the output buffer. this approach makes more sense when padding to a minimum field width might be required, and it's also closer to what wcsftime wants.
2013-08-22begin refactoring strftime to make adding field widths easierRich Felker1-151/+161
2013-08-21unbreak vwarn: print ": " before errno messageRich Felker1-2/+5
patch by Strake. this seems to be a regression caused by fixing the behavior of perror("") to match perror(0) at some point in the past.
2013-08-18fix fenv exception functions to mask their argumentSzabolcs Nagy8-18/+55
fesetround.c is a wrapper to do the arch independent argument check (on archs where rounding mode is not stored in 2 bits __fesetround still has to check its arguments) on powerpc fe*except functions do not accept the extra invalid flags of its fpscr register the useless FENV_ACCESS pragma was removed from feupdateenv
2013-08-18optimize x86 feclearexcept: only use save/restore x87 fenv if neededSzabolcs Nagy2-27/+38
the x87 exception summary (ES) and stack fault (SF) flags may be spuriously cleared by feclearexcept using the fnclex instruction, but these flags are not observable through libc hence maintaining their state is not critical.
2013-08-18add sse fenv support on i386 through hwcapSzabolcs Nagy2-9/+61
the sse and x87 rounding modes should be always the same, the visible exception flags are the bitwise or of the two fenv states (so it's enough to query the rounding mode or raise exceptions on one fenv)
2013-08-18fix i386 fesetenv: FE_DFL_ENV is (fenv_t*)-1 not 0Szabolcs Nagy1-2/+2
2013-08-17remove spurious tmp file present since initial git check-inRich Felker1-390/+0
2013-08-17add hkscs/big5-2003/eten extensions to iconv big5Rich Felker3-977/+1433
with these changes, the character set implemented as "big5" in musl is a pure superset of cp950, the canonical "big5", and agrees with the normative parts of Unicode. this means it has minor differences from both hkscs and big5-2003: - the range A2CC-A2CE maps to CJK ideographs rather than numerals, contrary to changes made in big5-2003. - C6CD maps to a CJK ideograph rather than its corresponding Kangxi radical character, contrary to changes made in hkscs. - F9FE maps to U+2593 rather than U+FFED. of these differences, none but the last are visually distinct, and the last is a character used purely for text-based graphics, not to convey linguistic content. should there be future demand for strict conformance to big5-2003 or hkscs mappings, the present charset aliases can be replaced with distinct variants. reportedly there are other non-standard big5 extensions in common use in Taiwan and perhaps elsewhere, which could also be added as layers on top of the existing big5 support. there may be additional characters which should be added to the hkscs table: the whatwg standard for big5 defines what appears to be a superset of hkscs.
2013-08-16some initial math asm for armhf (fabs[f] and sqrt[f])Rich Felker12-0/+32
2013-08-16support floating point environment (fenv) on armhf (hard float) subarchsRich Felker3-0/+62
patch by nsz. I've tested it on an armhf machine and it seems to be working correctly.
2013-08-16fix build of x86_64 expl assemblyRich Felker1-1/+1
apparently this label change was not carried over when adapting the changes from the i386 version.
2013-08-15math: fix pow(x,-1) to raise underflow properlySzabolcs Nagy1-2/+14
if FLT_EVAL_METHOD!=0 check if (double)(1/x) is subnormal and not a power of 2 (if 1/x is power of 2 then either it is exact or the long double to double rounding already raised inexact and underflow)