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* [RFC][PATCH] MIPS: IEEE 754-2008 NaN encoding support
@ 2013-08-22 23:53 Maciej W. Rozycki
  2013-08-23  0:58 ` Rich Felker
                   ` (2 more replies)
  0 siblings, 3 replies; 19+ messages in thread
From: Maciej W. Rozycki @ 2013-08-22 23:53 UTC (permalink / raw)
  To: libc-ports, libc-alpha; +Cc: Doug Gilmore

Hi,

 This change is sent as an RFC only at this time, because it relies on 
Linux kernel functionality that has not been integrated upstream yet.  
The minimum kernel version required set in this change has been therefore 
artificially fixed at 3.11.0, the current version number of the Linux 
kernel.  This requirement will be adjusted appropriately in the final 
version of this change.  Feedback is welcome on this implementation so 
that it can be swiftly integrated once the required kernel support has 
been put in place.

 Also I would appreciate if we could keep sysdeps/generic/ldconfig.h cache 
flag slots 0x0c00, 0x0d00 and 0x0e00 reserved from now on and until this 
change has been finally accepted.

 As many of you have been aware it has been a long practice for software 
using IEEE 754 floating-point arithmetic run on MIPS processors to use an 
encoding of Not-a-Number (NaN) data different to one used by software run 
on other processors.  And as of IEEE 754-2008 revision [1] this encoding 
does not follow one recommended in the standard, as specified in section 
6.2.1, where it is stated that quiet NaNs should have the first bit (d1) 
of their significand set to 1 while signalling NaNs should have that bit 
set to 0, but MIPS software interprets the two bits in the opposite 
manner.

 As from revision 3.50 [2][3] the MIPS Architecture provides for 
processors that support the IEEE 754-2008 preferred NaN encoding format.  
As the two formats (further referred to as "legacy NaN" and "2008 NaN") 
are incompatible to each other, tools will have to provide support for the 
two formats to help people avoid using incompatible binary modules.  Here 
is the glibc part.

 The change is comprised of two functional groups of features, both of 
which are required for correct support.

1. Dynamic linker support.

   To enforce the NaN encoding requirement in dynamic linking a new ELF 
   file header flag has been defined.  This flag is set for 2008-NaN 
   shared modules and executables and clear for legacy-NaN ones.  The 
   dynamic linker silently ignores any incompatible modules it encounters 
   in dependency processing.

   To avoid unnecessary processing of incompatible modules in the presence 
   of a shared module cache, a set of new cache flags has been defined to 
   mark 2008-NaN modules for the three ABIs supported.  Changes to
   sysdeps/unix/sysv/linux/mips/readelflib.c have been made following 
   an earlier code quality suggestion made here:

   http://sourceware.org/ml/libc-ports/2009-03/msg00036.html

   and are therefore a little bit more extensive than the minimum 
   required.

   Finally a new name has been defined for the dynamic linker so that 
   2008-NaN and legacy-NaN binaries can coexist on a single system that 
   supports dual-mode operation and that a legacy dynamic linker that 
   does not support verifying the 2008-NaN ELF file header flag is not 
   chosen to interpret a 2008-NaN binary by accident.

2. Floating environment support.

   IEEE 754-2008 features are controlled in the Floating-Point Control and 
   Status (FCSR) register and updates are needed to floating environment 
   support so that the 2008-NaN flag is set correctly and the kernel 
   default, inferred from the 2008-NaN ELF file header flag at the time 
   an executable is loaded, respected.

 As the NaN encoding format is a property of GCC code generation that is 
both a user-selected GCC configuration default and can be overridden with 
GCC options, code that needs to know what NaN encoding standard it has 
been configured for checks for the __mips_nan2008 macro that is defined 
internally by GCC whenever the 2008-NaN mode has been selected.  This mode 
is determined at the glibc configuration time and therefore a few 
consistency checks have been added to catch cases where compilation flags 
have been overridden by the user.

 The 2008 NaN set of features relies on kernel support as the in-kernel 
floating-point emulator needs to be aware of the NaN encoding used even on 
hard-float processors and configure the FPU context according to the value 
of the 2008 NaN ELF file header flag of the executable being started.  
Therefore the minimum version supported has been adjusted where glibc is 
built for the 2008 NaN encoding.  Legacy NaN encoding support is 
unaffected, older kernel versions remain supported.

 Preliminary mips-linux-gnu testing with the o32, n64 and n32 ABIs, legacy 
NaN showed no regressions.

 Questions, comments?

 References:

[1] "IEEE Standard for Floating-Point Arithmetic", IEEE Computer Society, 
    IEEE Std 754-2008, 29 August 2008

[2] "MIPS Architecture For Programmers, Volume I-A: Introduction to the 
    MIPS32 Architecture", MIPS Technologies, Inc., Document Number: 
    MD00082, Revision 3.50, September 20, 2012

[3] "MIPS Architecture For Programmers, Volume I-A: Introduction to the 
    MIPS64 Architecture", MIPS Technologies, Inc., Document Number: 
    MD00083, Revision 3.50, September 20, 2012

2012-08-22  Maciej W. Rozycki  <macro@codesourcery.com>

	ChangeLog:
	* config.h.in (HAVE_MIPS_NAN2008): New macro.
	* elf/elf.h (EF_MIPS_NAN2008): Likewise.
	* sysdeps/generic/ldconfig.h (FLAG_MIPS_LIB32_NAN2008): Likewise.
	(FLAG_MIPS64_LIBN32_NAN2008): Likewise.
	(FLAG_MIPS64_LIBN64_NAN2008): Likewise.
	* elf/cache.c (print_entry): Handle the new cache flags.

	ports/ChangeLog.mips
	* sysdeps/mips/dl-machine.h (ELF_MACHINE_NAN2008): New macro.
	(elf_machine_matches_host): Reject objects that use a different
	NaN encoding convention.
	* sysdeps/mips/fpu_control.h: Document IEEE 754-2008 feature 
	control bits.
	(_FPU_ABS2008, _FPU_NAN2008): New macros.
	(_FPU_RESERVED): Clear bits #20 and #19.
	(_FPU_DEFAULT) [__mips_nan2008]: Set bit #18.
	(_FPU_IEEE) [__mips_nan2008]: Likewise.
	* sysdeps/mips/mips64/soft-fp/sfp-machine.h [__mips_nan2008]
	(_FP_NANFRAC_S, _FP_NANFRAC_D, _FP_NANFRAC_Q): Define 2008-NaN
	payloads.
	(_FP_QNANNEGATEDP): Set to 0.
	* sysdeps/mips/soft-fp/sfp-machine.h [__mips_nan2008]
	(_FP_NANFRAC_S, _FP_NANFRAC_D, _FP_NANFRAC_Q): Define 2008-NaN
	payloads.
	(_FP_QNANNEGATEDP): Set to 0.
	* sysdeps/unix/sysv/linux/mips/dl-cache.h (_DL_CACHE_DEFAULT_ID): 
	Define 2008 NaN encoding values.
	* sysdeps/mips/fpu/fesetenv.c (fesetenv): Do not allow to flip
	the _FPU_NAN2008 bit.
	* sysdeps/unix/sysv/linux/mips/readelflib.c (process_elf_file):
	Handle 2008-NaN libraries.
	* sysdeps/mips/shlib-versions [HAVE_MIPS_NAN2008]: Set 
	ld=ld-linux-mipsn8.so.1.
	* sysdeps/mips/configure.in: Define HAVE_MIPS_NAN2008 if the
	2008 NaN encoding is used.
	* sysdeps/unix/sysv/linux/mips/configure.in: Set 
	arch_minimum_kernel to 3.11.0 if 2008 NaN encoding is used.
	* sysdeps/mips/configure: Regenerate.
	* sysdeps/unix/sysv/linux/mips/configure: Regenerate.

  Maciej

glibc-mips-nan2008.diff
Index: glibc-fsf-trunk-quilt/config.h.in
===================================================================
--- glibc-fsf-trunk-quilt.orig/config.h.in	2013-08-20 15:18:10.000000000 +0100
+++ glibc-fsf-trunk-quilt/config.h.in	2013-08-22 10:32:05.447640501 +0100
@@ -241,4 +241,8 @@
 /* The pt_chown binary is being built and used by grantpt.  */
 #undef HAVE_PT_CHOWN
 
+/* ports/sysdeps/mips/configure.in  */
+/* Define if using the IEEE 754-2008 NaN encoding on the MIPS target.  */
+#undef HAVE_MIPS_NAN2008
+
 #endif
Index: glibc-fsf-trunk-quilt/elf/cache.c
===================================================================
--- glibc-fsf-trunk-quilt.orig/elf/cache.c	2013-05-21 00:20:30.000000000 +0100
+++ glibc-fsf-trunk-quilt/elf/cache.c	2013-08-22 10:32:05.447640501 +0100
@@ -105,6 +105,15 @@ print_entry (const char *lib, int flag, 
     case FLAG_ARM_LIBSF:
       fputs (",soft-float", stdout);
       break;
+    case FLAG_MIPS_LIB32_NAN2008:
+      fputs (",nan2008", stdout);
+      break;
+    case FLAG_MIPS64_LIBN32_NAN2008:
+      fputs (",N32,nan2008", stdout);
+      break;
+    case FLAG_MIPS64_LIBN64_NAN2008:
+      fputs (",64bit,nan2008", stdout);
+      break;
     case 0:
       break;
     default:
Index: glibc-fsf-trunk-quilt/elf/elf.h
===================================================================
--- glibc-fsf-trunk-quilt.orig/elf/elf.h	2013-06-26 18:42:44.000000000 +0100
+++ glibc-fsf-trunk-quilt/elf/elf.h	2013-08-22 10:32:05.447640501 +0100
@@ -1383,6 +1383,7 @@ typedef struct
 #define EF_MIPS_64BIT_WHIRL	16
 #define EF_MIPS_ABI2		32
 #define EF_MIPS_ABI_ON32	64
+#define EF_MIPS_NAN2008	1024  /* Uses IEEE 754-2008 NaN encoding.  */
 #define EF_MIPS_ARCH		0xf0000000 /* MIPS architecture level.  */
 
 /* Legal values for MIPS architecture level.  */
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/configure
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/configure	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/configure	2013-08-22 10:32:05.447640501 +0100
@@ -1,3 +1,163 @@
 # This file is generated from configure.in by Autoconf.  DO NOT EDIT!
  # Local configure fragment for sysdeps/mips.
 
+
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for grep that handles long lines and -e" >&5
+$as_echo_n "checking for grep that handles long lines and -e... " >&6; }
+if ${ac_cv_path_GREP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -z "$GREP"; then
+  ac_path_GREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in grep ggrep; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_GREP="$as_dir/$ac_prog$ac_exec_ext"
+      { test -f "$ac_path_GREP" && $as_test_x "$ac_path_GREP"; } || continue
+# Check for GNU ac_path_GREP and select it if it is found.
+  # Check for GNU $ac_path_GREP
+case `"$ac_path_GREP" --version 2>&1` in
+*GNU*)
+  ac_cv_path_GREP="$ac_path_GREP" ac_path_GREP_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo 'GREP' >> "conftest.nl"
+    "$ac_path_GREP" -e 'GREP$' -e '-(cannot match)-' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_GREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_GREP="$ac_path_GREP"
+      ac_path_GREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_GREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_GREP"; then
+    as_fn_error $? "no acceptable grep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_GREP=$GREP
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_GREP" >&5
+$as_echo "$ac_cv_path_GREP" >&6; }
+ GREP="$ac_cv_path_GREP"
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for egrep" >&5
+$as_echo_n "checking for egrep... " >&6; }
+if ${ac_cv_path_EGREP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if echo a | $GREP -E '(a|b)' >/dev/null 2>&1
+   then ac_cv_path_EGREP="$GREP -E"
+   else
+     if test -z "$EGREP"; then
+  ac_path_EGREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in egrep; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_EGREP="$as_dir/$ac_prog$ac_exec_ext"
+      { test -f "$ac_path_EGREP" && $as_test_x "$ac_path_EGREP"; } || continue
+# Check for GNU ac_path_EGREP and select it if it is found.
+  # Check for GNU $ac_path_EGREP
+case `"$ac_path_EGREP" --version 2>&1` in
+*GNU*)
+  ac_cv_path_EGREP="$ac_path_EGREP" ac_path_EGREP_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo 'EGREP' >> "conftest.nl"
+    "$ac_path_EGREP" 'EGREP$' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_EGREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_EGREP="$ac_path_EGREP"
+      ac_path_EGREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_EGREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_EGREP"; then
+    as_fn_error $? "no acceptable egrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_EGREP=$EGREP
+fi
+
+   fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_EGREP" >&5
+$as_echo "$ac_cv_path_EGREP" >&6; }
+ EGREP="$ac_cv_path_EGREP"
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler is using the 2008 NaN encoding" >&5
+$as_echo_n "checking whether the compiler is using the 2008 NaN encoding... " >&6; }
+if ${libc_cv_mips_nan2008+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+dnl
+#ifdef __mips_nan2008
+yes
+#endif
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "yes" >/dev/null 2>&1; then :
+  libc_cv_mips_nan2008=yes
+else
+  libc_cv_mips_nan2008=no
+fi
+rm -f conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_mips_nan2008" >&5
+$as_echo "$libc_cv_mips_nan2008" >&6; }
+if test x$libc_cv_mips_nan2008 = xyes; then
+  $as_echo "#define HAVE_MIPS_NAN2008 1" >>confdefs.h
+
+fi
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/configure.in
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/configure.in	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/configure.in	2013-08-22 10:32:05.447640501 +0100
@@ -4,3 +4,12 @@ GLIBC_PROVIDES dnl See aclocal.m4 in the
 dnl No MIPS GCC supports accessing static and hidden symbols in an
 dnl position independent way.
 dnl AC_DEFINE(PI_STATIC_AND_HIDDEN)
+
+AC_CACHE_CHECK([whether the compiler is using the 2008 NaN encoding],
+  libc_cv_mips_nan2008, [AC_EGREP_CPP(yes, [dnl
+#ifdef __mips_nan2008
+yes
+#endif], libc_cv_mips_nan2008=yes, libc_cv_mips_nan2008=no)])
+if test x$libc_cv_mips_nan2008 = xyes; then
+  AC_DEFINE(HAVE_MIPS_NAN2008)
+fi
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/dl-machine.h
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/dl-machine.h	2013-05-30 00:49:41.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/dl-machine.h	2013-08-22 10:32:05.447640501 +0100
@@ -73,6 +73,16 @@ do { if ((l)->l_info[DT_MIPS (RLD_MAP)])
        (ElfW(Addr)) (r); \
    } while (0)
 
+#if ((defined __mips_nan2008 && !defined HAVE_MIPS_NAN2008) \
+     || (!defined __mips_nan2008 && defined HAVE_MIPS_NAN2008))
+# error "Configuration inconsistency: __mips_nan2008 != HAVE_MIPS_NAN2008, overridden CFLAGS?"
+#endif
+#ifdef __mips_nan2008
+# define ELF_MACHINE_NAN2008 EF_MIPS_NAN2008
+#else
+# define ELF_MACHINE_NAN2008 0
+#endif
+
 /* Return nonzero iff ELF header is compatible with the running host.  */
 static inline int __attribute_used__
 elf_machine_matches_host (const ElfW(Ehdr) *ehdr)
@@ -83,6 +93,10 @@ elf_machine_matches_host (const ElfW(Ehd
     return 0;
 #endif
 
+  /* Don't link 2008-NaN and legacy-NaN objects together.  */
+  if ((ehdr->e_flags & EF_MIPS_NAN2008) != ELF_MACHINE_NAN2008)
+    return 0;
+
   switch (ehdr->e_machine)
     {
     case EM_MIPS:
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/fpu/fesetenv.c
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/fpu/fesetenv.c	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/fpu/fesetenv.c	2013-08-22 10:32:05.447640501 +0100
@@ -25,15 +25,16 @@ fesetenv (const fenv_t *envp)
 {
   fpu_control_t cw;
 
-  /* Read first current state to flush fpu pipeline.  */
   _FPU_GETCW (cw);
 
   if (envp == FE_DFL_ENV)
-    _FPU_SETCW (_FPU_DEFAULT);
+    cw = _FPU_DEFAULT;
   else if (envp == FE_NOMASK_ENV)
-    _FPU_SETCW (_FPU_IEEE);
+    cw = _FPU_IEEE;
   else
-    _FPU_SETCW (envp->__fp_control_register);
+    cw = (cw & _FPU_NAN2008) | (envp->__fp_control_register & ~_FPU_NAN2008);
+
+  _FPU_SETCW (cw);
 
   /* Success.  */
   return 0;
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/fpu_control.h
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/fpu_control.h	2013-08-21 07:35:44.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/fpu_control.h	2013-08-22 10:32:05.447640501 +0100
@@ -29,7 +29,9 @@
  *           available for MIPS III and newer.
  * 23     -> Condition bit
  * 22-21  -> reserved for architecture implementers
- * 20-18  -> reserved (read as 0, write with 0)
+ * 20     -> reserved (read as 0, write with 0)
+ * 19     -> IEEE 754-2008 non-arithmetic ABS.fmt and NEG.fmt enable
+ * 18     -> IEEE 754-2008 recommended NaN encoding enable
  * 17     -> cause bit for unimplemented operation
  * 16     -> cause bit for invalid exception
  * 15     -> cause bit for division by zero exception
@@ -79,22 +81,33 @@ extern fpu_control_t __fpu_control;
 /* flush denormalized numbers to zero */
 #define _FPU_FLUSH_TZ   0x1000000
 
+/* IEEE 754-2008 compliance control.  */
+#define _FPU_ABS2008    0x80000
+#define _FPU_NAN2008    0x40000
+
 /* rounding control */
 #define _FPU_RC_NEAREST 0x0     /* RECOMMENDED */
 #define _FPU_RC_ZERO    0x1
 #define _FPU_RC_UP      0x2
 #define _FPU_RC_DOWN    0x3
 
-#define _FPU_RESERVED 0xfe9c0000  /* Reserved bits in cw */
+#define _FPU_RESERVED 0xfe840000  /* Reserved bits in cw, incl NAN2008.  */
 
 
 /* The fdlibm code requires strict IEEE double precision arithmetic,
    and no interrupts for exceptions, rounding to nearest.  */
-
+#ifdef __mips_nan2008
+#define _FPU_DEFAULT  0x00040000
+#else
 #define _FPU_DEFAULT  0x00000000
+#endif
 
-/* IEEE:  same as above, but exceptions */
+/* IEEE: same as above, but exceptions.  */
+#ifdef __mips_nan2008
+#define _FPU_IEEE     0x00040F80
+#else
 #define _FPU_IEEE     0x00000F80
+#endif
 
 /* Type of the control word.  */
 typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__SI__)));
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/mips64/soft-fp/sfp-machine.h
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/mips64/soft-fp/sfp-machine.h	2013-08-20 15:18:10.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/mips64/soft-fp/sfp-machine.h	2013-08-22 10:32:05.447640501 +0100
@@ -24,15 +24,25 @@
 #define _FP_DIV_MEAT_D(R,X,Y)	_FP_DIV_MEAT_1_udiv_norm(D,R,X,Y)
 #define _FP_DIV_MEAT_Q(R,X,Y)	_FP_DIV_MEAT_2_udiv(Q,R,X,Y)
 
-#define _FP_NANFRAC_S		(_FP_QNANBIT_S - 1)
-#define _FP_NANFRAC_D		(_FP_QNANBIT_D - 1)
-#define _FP_NANFRAC_Q		(_FP_QNANBIT_Q - 1), -1
+#ifdef __mips_nan2008
+# define _FP_NANFRAC_S		((_FP_QNANBIT_S << 1) - 1)
+# define _FP_NANFRAC_D		((_FP_QNANBIT_D << 1) - 1)
+# define _FP_NANFRAC_Q		((_FP_QNANBIT_Q << 1) - 1), -1
+#else
+# define _FP_NANFRAC_S		(_FP_QNANBIT_S - 1)
+# define _FP_NANFRAC_D		(_FP_QNANBIT_D - 1)
+# define _FP_NANFRAC_Q		(_FP_QNANBIT_Q - 1), -1
+#endif
 #define _FP_NANSIGN_S		0
 #define _FP_NANSIGN_D		0
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
-#define _FP_QNANNEGATEDP 1
+#ifdef __mips_nan2008
+# define _FP_QNANNEGATEDP 0
+#else
+# define _FP_QNANNEGATEDP 1
+#endif
 
 /* From my experiments it seems X is chosen unless one of the
    NaNs is sNaN,  in which case the result is NANSIGN/NANFRAC.  */
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/shlib-versions
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/shlib-versions	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/shlib-versions	2013-08-22 10:32:05.447640501 +0100
@@ -3,7 +3,11 @@ mips.*-.*-linux.*	libm=6			GLIBC_2.0 GLI
 # Working mips versions were never released between 2.0 and 2.2.
 mips.*-.*-linux.*	libc=6			GLIBC_2.0 GLIBC_2.2
 
+%ifdef HAVE_MIPS_NAN2008
+mips.*-.*-linux.*	ld=ld-linux-mipsn8.so.1	GLIBC_2.0 GLIBC_2.2
+%else
 mips.*-.*-linux.*	ld=ld.so.1		GLIBC_2.0 GLIBC_2.2
+%endif
 mips.*-.*-linux.*	libdl=2			GLIBC_2.0 GLIBC_2.2
 
 mips.*-.*-linux.*	libresolv=2		GLIBC_2.0 GLIBC_2.2
Index: glibc-fsf-trunk-quilt/ports/sysdeps/mips/soft-fp/sfp-machine.h
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/mips/soft-fp/sfp-machine.h	2013-08-20 15:18:10.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/mips/soft-fp/sfp-machine.h	2013-08-22 10:32:05.447640501 +0100
@@ -21,15 +21,25 @@
 #define _FP_DIV_MEAT_D(R,X,Y)	_FP_DIV_MEAT_2_udiv(D,R,X,Y)
 #define _FP_DIV_MEAT_Q(R,X,Y)	_FP_DIV_MEAT_4_udiv(Q,R,X,Y)
 
-#define _FP_NANFRAC_S		(_FP_QNANBIT_S - 1)
-#define _FP_NANFRAC_D		(_FP_QNANBIT_D - 1), -1
-#define _FP_NANFRAC_Q		(_FP_QNANBIT_Q - 1), -1, -1, -1
+#ifdef __mips_nan2008
+# define _FP_NANFRAC_S		((_FP_QNANBIT_S << 1) - 1)
+# define _FP_NANFRAC_D		((_FP_QNANBIT_D << 1) - 1), -1
+# define _FP_NANFRAC_Q		((_FP_QNANBIT_Q << 1) - 1), -1, -1, -1
+#else
+# define _FP_NANFRAC_S		(_FP_QNANBIT_S - 1)
+# define _FP_NANFRAC_D		(_FP_QNANBIT_D - 1), -1
+# define _FP_NANFRAC_Q		(_FP_QNANBIT_Q - 1), -1, -1, -1
+#endif
 #define _FP_NANSIGN_S		0
 #define _FP_NANSIGN_D		0
 #define _FP_NANSIGN_Q		0
 
 #define _FP_KEEPNANFRACP 1
-#define _FP_QNANNEGATEDP 1
+#ifdef __mips_nan2008
+# define _FP_QNANNEGATEDP 0
+#else
+# define _FP_QNANNEGATEDP 1
+#endif
 
 /* From my experiments it seems X is chosen unless one of the
    NaNs is sNaN,  in which case the result is NANSIGN/NANFRAC.  */
Index: glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/configure
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/unix/sysv/linux/mips/configure	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/configure	2013-08-22 10:39:07.378109215 +0100
@@ -137,4 +137,165 @@ case "$prefix" in
   esac
 esac
 
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for grep that handles long lines and -e" >&5
+$as_echo_n "checking for grep that handles long lines and -e... " >&6; }
+if ${ac_cv_path_GREP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if test -z "$GREP"; then
+  ac_path_GREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in grep ggrep; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_GREP="$as_dir/$ac_prog$ac_exec_ext"
+      { test -f "$ac_path_GREP" && $as_test_x "$ac_path_GREP"; } || continue
+# Check for GNU ac_path_GREP and select it if it is found.
+  # Check for GNU $ac_path_GREP
+case `"$ac_path_GREP" --version 2>&1` in
+*GNU*)
+  ac_cv_path_GREP="$ac_path_GREP" ac_path_GREP_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo 'GREP' >> "conftest.nl"
+    "$ac_path_GREP" -e 'GREP$' -e '-(cannot match)-' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_GREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_GREP="$ac_path_GREP"
+      ac_path_GREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_GREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_GREP"; then
+    as_fn_error $? "no acceptable grep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_GREP=$GREP
+fi
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_GREP" >&5
+$as_echo "$ac_cv_path_GREP" >&6; }
+ GREP="$ac_cv_path_GREP"
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for egrep" >&5
+$as_echo_n "checking for egrep... " >&6; }
+if ${ac_cv_path_EGREP+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  if echo a | $GREP -E '(a|b)' >/dev/null 2>&1
+   then ac_cv_path_EGREP="$GREP -E"
+   else
+     if test -z "$EGREP"; then
+  ac_path_EGREP_found=false
+  # Loop through the user's path and test for each of PROGNAME-LIST
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH$PATH_SEPARATOR/usr/xpg4/bin
+do
+  IFS=$as_save_IFS
+  test -z "$as_dir" && as_dir=.
+    for ac_prog in egrep; do
+    for ac_exec_ext in '' $ac_executable_extensions; do
+      ac_path_EGREP="$as_dir/$ac_prog$ac_exec_ext"
+      { test -f "$ac_path_EGREP" && $as_test_x "$ac_path_EGREP"; } || continue
+# Check for GNU ac_path_EGREP and select it if it is found.
+  # Check for GNU $ac_path_EGREP
+case `"$ac_path_EGREP" --version 2>&1` in
+*GNU*)
+  ac_cv_path_EGREP="$ac_path_EGREP" ac_path_EGREP_found=:;;
+*)
+  ac_count=0
+  $as_echo_n 0123456789 >"conftest.in"
+  while :
+  do
+    cat "conftest.in" "conftest.in" >"conftest.tmp"
+    mv "conftest.tmp" "conftest.in"
+    cp "conftest.in" "conftest.nl"
+    $as_echo 'EGREP' >> "conftest.nl"
+    "$ac_path_EGREP" 'EGREP$' < "conftest.nl" >"conftest.out" 2>/dev/null || break
+    diff "conftest.out" "conftest.nl" >/dev/null 2>&1 || break
+    as_fn_arith $ac_count + 1 && ac_count=$as_val
+    if test $ac_count -gt ${ac_path_EGREP_max-0}; then
+      # Best one so far, save it but keep looking for a better one
+      ac_cv_path_EGREP="$ac_path_EGREP"
+      ac_path_EGREP_max=$ac_count
+    fi
+    # 10*(2^10) chars as input seems more than enough
+    test $ac_count -gt 10 && break
+  done
+  rm -f conftest.in conftest.tmp conftest.nl conftest.out;;
+esac
+
+      $ac_path_EGREP_found && break 3
+    done
+  done
+  done
+IFS=$as_save_IFS
+  if test -z "$ac_cv_path_EGREP"; then
+    as_fn_error $? "no acceptable egrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+  fi
+else
+  ac_cv_path_EGREP=$EGREP
+fi
+
+   fi
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_path_EGREP" >&5
+$as_echo "$ac_cv_path_EGREP" >&6; }
+ EGREP="$ac_cv_path_EGREP"
+
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether the compiler is using the 2008 NaN encoding" >&5
+$as_echo_n "checking whether the compiler is using the 2008 NaN encoding... " >&6; }
+if ${libc_cv_mips_nan2008+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+dnl
+#ifdef __mips_nan2008
+yes
+#endif
+_ACEOF
+if (eval "$ac_cpp conftest.$ac_ext") 2>&5 |
+  $EGREP "yes" >/dev/null 2>&1; then :
+  libc_cv_mips_nan2008=yes
+else
+  libc_cv_mips_nan2008=no
+fi
+rm -f conftest*
+
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $libc_cv_mips_nan2008" >&5
+$as_echo "$libc_cv_mips_nan2008" >&6; }
+
 libc_cv_gcc_unwind_find_fde=yes
+
+if test -z "$arch_minimum_kernel"; then
+  if test x$libc_cv_mips_nan2008 = xyes; then
+    arch_minimum_kernel=3.11.0
+  fi
+fi
Index: glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/configure.in
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/unix/sysv/linux/mips/configure.in	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/configure.in	2013-08-22 10:35:13.417814395 +0100
@@ -75,4 +75,16 @@ case "$prefix" in
   esac
 esac
 
+AC_CACHE_CHECK([whether the compiler is using the 2008 NaN encoding],
+  libc_cv_mips_nan2008, [AC_EGREP_CPP(yes, [dnl
+#ifdef __mips_nan2008
+yes
+#endif], libc_cv_mips_nan2008=yes, libc_cv_mips_nan2008=no)])
+
 libc_cv_gcc_unwind_find_fde=yes
+
+if test -z "$arch_minimum_kernel"; then
+  if test x$libc_cv_mips_nan2008 = xyes; then
+    arch_minimum_kernel=3.11.0
+  fi
+fi
Index: glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/dl-cache.h
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/unix/sysv/linux/mips/dl-cache.h	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/dl-cache.h	2013-08-22 10:32:05.447640501 +0100
@@ -18,11 +18,27 @@
 
 #include <ldconfig.h>
 
-/* Redefine the cache ID for new ABIs; o32 keeps using the generic check.  */
-#if _MIPS_SIM == _ABI64
-# define _DL_CACHE_DEFAULT_ID	(FLAG_MIPS64_LIBN64 | FLAG_ELF_LIBC6)
-#elif _MIPS_SIM == _ABIN32
-# define _DL_CACHE_DEFAULT_ID	(FLAG_MIPS64_LIBN32 | FLAG_ELF_LIBC6)
+#if ((defined __mips_nan2008 && !defined HAVE_MIPS_NAN2008) \
+     || (!defined __mips_nan2008 && defined HAVE_MIPS_NAN2008))
+# error "Configuration inconsistency: __mips_nan2008 != HAVE_MIPS_NAN2008, overridden CFLAGS?"
+#endif
+
+/* Redefine the cache ID for new ABIs and 2008 NaN support; legacy o32
+   keeps using the generic check.  */
+#ifdef __mips_nan2008
+# if _MIPS_SIM == _ABIO32
+#  define _DL_CACHE_DEFAULT_ID	(FLAG_MIPS_LIB32_NAN2008 | FLAG_ELF_LIBC6)
+# elif _MIPS_SIM == _ABI64
+#  define _DL_CACHE_DEFAULT_ID	(FLAG_MIPS64_LIBN64_NAN2008 | FLAG_ELF_LIBC6)
+# elif _MIPS_SIM == _ABIN32
+#  define _DL_CACHE_DEFAULT_ID	(FLAG_MIPS64_LIBN32_NAN2008 | FLAG_ELF_LIBC6)
+# endif
+#else
+# if _MIPS_SIM == _ABI64
+#  define _DL_CACHE_DEFAULT_ID	(FLAG_MIPS64_LIBN64 | FLAG_ELF_LIBC6)
+# elif _MIPS_SIM == _ABIN32
+#  define _DL_CACHE_DEFAULT_ID	(FLAG_MIPS64_LIBN32 | FLAG_ELF_LIBC6)
+# endif
 #endif
 
 #ifdef _DL_CACHE_DEFAULT_ID
Index: glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/readelflib.c
===================================================================
--- glibc-fsf-trunk-quilt.orig/ports/sysdeps/unix/sysv/linux/mips/readelflib.c	2013-05-16 18:17:13.000000000 +0100
+++ glibc-fsf-trunk-quilt/ports/sysdeps/unix/sysv/linux/mips/readelflib.c	2013-08-22 10:32:05.447640501 +0100
@@ -33,19 +33,32 @@ process_elf_file (const char *file_name,
 		  unsigned int *osversion, char **soname, void *file_contents,
 		  size_t file_length)
 {
-  ElfW(Ehdr) *elf_header = (ElfW(Ehdr) *) file_contents;
+  union
+    {
+      Elf64_Ehdr *eh64;
+      Elf32_Ehdr *eh32;
+      ElfW(Ehdr) *eh;
+    }
+  elf_header;
   int ret;
 
-  if (elf_header->e_ident [EI_CLASS] == ELFCLASS32)
+  elf_header.eh = file_contents;
+  if (elf_header.eh->e_ident [EI_CLASS] == ELFCLASS32)
     {
-      Elf32_Ehdr *elf32_header = (Elf32_Ehdr *) elf_header;
-
       ret = process_elf32_file (file_name, lib, flag, osversion, soname,
 				file_contents, file_length);
+      if (!ret)
+	{
+	  Elf32_Word flags = elf_header.eh32->e_flags;
+	  int nan2008 = (flags & EF_MIPS_NAN2008) != 0;
 
-      /* n32 libraries are always libc.so.6+.  */
-      if (!ret && (elf32_header->e_flags & EF_MIPS_ABI2) != 0)
-	*flag = FLAG_MIPS64_LIBN32|FLAG_ELF_LIBC6;
+	  /* n32 libraries are always libc.so.6+, o32 only if 2008 NaN.  */
+	  if ((flags & EF_MIPS_ABI2) != 0)
+	    *flag = (nan2008 ? FLAG_MIPS64_LIBN32_NAN2008
+		     : FLAG_MIPS64_LIBN32) | FLAG_ELF_LIBC6;
+	  else if (nan2008)
+	    *flag = FLAG_MIPS_LIB32_NAN2008 | FLAG_ELF_LIBC6;
+	}
     }
   else
     {
@@ -53,7 +66,13 @@ process_elf_file (const char *file_name,
 				file_contents, file_length);
       /* n64 libraries are always libc.so.6+.  */
       if (!ret)
-	*flag = FLAG_MIPS64_LIBN64|FLAG_ELF_LIBC6;
+	{
+	  Elf64_Word flags = elf_header.eh64->e_flags;
+	  int nan2008 = (flags & EF_MIPS_NAN2008) != 0;
+
+	  *flag = (nan2008 ? FLAG_MIPS64_LIBN64_NAN2008
+		   : FLAG_MIPS64_LIBN64) | FLAG_ELF_LIBC6;
+	}
     }
 
   return ret;
Index: glibc-fsf-trunk-quilt/sysdeps/generic/ldconfig.h
===================================================================
--- glibc-fsf-trunk-quilt.orig/sysdeps/generic/ldconfig.h	2013-05-21 00:20:30.000000000 +0100
+++ glibc-fsf-trunk-quilt/sysdeps/generic/ldconfig.h	2013-08-22 10:32:05.447640501 +0100
@@ -21,24 +21,27 @@
 
 #include <stdint.h>
 
-#define FLAG_ANY		-1
-#define FLAG_TYPE_MASK		0x00ff
-#define FLAG_LIBC4		0x0000
-#define FLAG_ELF		0x0001
-#define FLAG_ELF_LIBC5		0x0002
-#define FLAG_ELF_LIBC6		0x0003
-#define FLAG_REQUIRED_MASK	0xff00
-#define FLAG_SPARC_LIB64	0x0100
-#define FLAG_IA64_LIB64		0x0200
-#define FLAG_X8664_LIB64	0x0300
-#define FLAG_S390_LIB64		0x0400
-#define FLAG_POWERPC_LIB64	0x0500
-#define FLAG_MIPS64_LIBN32	0x0600
-#define FLAG_MIPS64_LIBN64	0x0700
-#define FLAG_X8664_LIBX32	0x0800
-#define FLAG_ARM_LIBHF		0x0900
-#define FLAG_AARCH64_LIB64	0x0a00
-#define FLAG_ARM_LIBSF		0x0b00
+#define FLAG_ANY			-1
+#define FLAG_TYPE_MASK			0x00ff
+#define FLAG_LIBC4			0x0000
+#define FLAG_ELF			0x0001
+#define FLAG_ELF_LIBC5			0x0002
+#define FLAG_ELF_LIBC6			0x0003
+#define FLAG_REQUIRED_MASK		0xff00
+#define FLAG_SPARC_LIB64		0x0100
+#define FLAG_IA64_LIB64			0x0200
+#define FLAG_X8664_LIB64		0x0300
+#define FLAG_S390_LIB64			0x0400
+#define FLAG_POWERPC_LIB64		0x0500
+#define FLAG_MIPS64_LIBN32		0x0600
+#define FLAG_MIPS64_LIBN64		0x0700
+#define FLAG_X8664_LIBX32		0x0800
+#define FLAG_ARM_LIBHF			0x0900
+#define FLAG_AARCH64_LIB64		0x0a00
+#define FLAG_ARM_LIBSF			0x0b00
+#define FLAG_MIPS_LIB32_NAN2008		0x0c00
+#define FLAG_MIPS64_LIBN32_NAN2008	0x0d00
+#define FLAG_MIPS64_LIBN64_NAN2008	0x0e00
 
 /* Name of auxiliary cache.  */
 #define _PATH_LDCONFIG_AUX_CACHE "/var/cache/ldconfig/aux-cache"

^ permalink raw reply	[flat|nested] 19+ messages in thread

end of thread, other threads:[~2013-09-18 20:48 UTC | newest]

Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-08-22 23:53 [RFC][PATCH] MIPS: IEEE 754-2008 NaN encoding support Maciej W. Rozycki
2013-08-23  0:58 ` Rich Felker
2013-08-23  1:41   ` Maciej W. Rozycki
2013-08-23  1:57     ` Rich Felker
2013-08-23  3:11       ` pinskia
2013-08-23  3:38         ` Rich Felker
2013-08-23  4:08           ` pinskia
2013-08-23  4:12             ` Rich Felker
2013-08-23  4:10     ` Rich Felker
2013-08-23  3:46 ` Rich Felker
2013-08-23 10:53   ` Maciej W. Rozycki
2013-08-23 15:26 ` Joseph S. Myers
2013-09-05 22:47   ` [RFC][PATCH v2] " Maciej W. Rozycki
2013-09-06 16:24     ` Joseph S. Myers
2013-09-10  9:36       ` Maciej W. Rozycki
2013-09-10 23:24         ` Joseph S. Myers
2013-09-16 15:14           ` [PATCH v3] " Maciej W. Rozycki
2013-09-16 15:26             ` Joseph S. Myers
2013-09-18 20:48               ` Maciej W. Rozycki

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