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Re: PowerPC's math_ldbl.h
On 02/22/2013 12:46 PM, Joseph S. Myers wrote:
> On Fri, 22 Feb 2013, Adhemerval Zanella wrote:
>
>> * sysdeps/unix/sysv/linux/powerpc/Implies: Add powerpc/fpu prior to
>> ieee754/ldbl-128ibm so sysdeps/powerpc/fpu/math_ldbl.h will be included
>> first.
> That's wrong - powerpc --without-fp will be using
> sysdeps/unix/sysv/linux/powerpc but can't use sysdeps/powerpc/fpu.
>
Indeed I didn't take nofpu in consideration. This patch now removes the
sysdeps/unix/sysv/linux/powerpc/Implies and adds the ldbl after ldbl-opt
on sysdeps/powerpc/Implies. This makes sysdeps/powerpc/fpu not appear with
nofpu build while add making it show before sysdeps/ieee754/ldbl-128ibm
so the PPC specific optimization is still used.
2013-02-22 Adhemerval Zanella <azanella@linux.vnet.ibm.com>
* sysdeps/ieee754/ldbl-128ibm/math_ldbl.h (ldbl_pack): Renamed to
default_ldbl_pack and using as default implementation.
(ldbl_unpack): Renamed to default_ldbl_unpack and using as default
implementation.
* sysdeps/powerpc/fpu/math_ldbl.h (ldbl_extract_mantissa): removed
redundant definition.
(ldbl_insert_mantissa): Likewise.
(ldbl_canonicalize): Likewise.
(ldbl_nearbyint): Likewise.
(ldbl_pack): Renamed to ldbl_pack_ppc.
(ldbl_unpack): Renamed to ldbl_unpack_ppc.
* sysdeps/unix/sysv/linux/powerpc/Implies: Remove file.
* sysdeps/powerpc/Implies: Add ieee754/ldbl-opt after ieee754/ldbl-128ibm.
--
diff --git a/sysdeps/ieee754/ldbl-128ibm/math_ldbl.h b/sysdeps/ieee754/ldbl-128ibm/math_ldbl.h
index be9ac71..1cce1fc 100644
--- a/sysdeps/ieee754/ldbl-128ibm/math_ldbl.h
+++ b/sysdeps/ieee754/ldbl-128ibm/math_ldbl.h
@@ -125,7 +125,7 @@ ldbl_insert_mantissa (int sign, int exp, int64_t hi64, u_int64_t lo64)
/* Handy utility functions to pack/unpack/cononicalize and find the nearbyint
of long double implemented as double double. */
static inline long double
-ldbl_pack (double a, double aa)
+default_ldbl_pack (double a, double aa)
{
union ibm_extended_long_double u;
u.dd[0] = a;
@@ -134,7 +134,7 @@ ldbl_pack (double a, double aa)
}
static inline void
-ldbl_unpack (long double l, double *a, double *aa)
+default_ldbl_unpack (long double l, double *a, double *aa)
{
union ibm_extended_long_double u;
u.d = l;
@@ -142,6 +142,12 @@ ldbl_unpack (long double l, double *a, double *aa)
*aa = u.dd[1];
}
+#ifndef ldbl_pack
+# define ldbl_pack default_ldbl_pack
+#endif
+#ifndef ldbl_unpack
+# define ldbl_unpack default_ldbl_unpack
+#endif
/* Convert a finite long double to canonical form.
Does not handle +/-Inf properly. */
diff --git a/sysdeps/powerpc/Implies b/sysdeps/powerpc/Implies
index 7ccf9a7..78dba95 100644
--- a/sysdeps/powerpc/Implies
+++ b/sysdeps/powerpc/Implies
@@ -1,4 +1,5 @@
# On PowerPC we use the IBM extended long double format.
ieee754/ldbl-128ibm
+ieee754/ldbl-opt
ieee754/dbl-64
ieee754/flt-32
diff --git a/sysdeps/powerpc/fpu/math_ldbl.h b/sysdeps/powerpc/fpu/math_ldbl.h
index 20224e6..36378c0 100644
--- a/sysdeps/powerpc/fpu/math_ldbl.h
+++ b/sysdeps/powerpc/fpu/math_ldbl.h
@@ -2,132 +2,12 @@
#error "Never use <math_ldbl.h> directly; include <math_private.h> instead."
#endif
-#include <sysdeps/ieee754/ldbl-128/math_ldbl.h>
-#include <ieee754.h>
-
-static inline void
-ldbl_extract_mantissa (int64_t *hi64, u_int64_t *lo64, int *exp, long double x)
-{
- /* We have 105 bits of mantissa plus one implicit digit. Since
- 106 bits are representable we use the first implicit digit for
- the number before the decimal point and the second implicit bit
- as bit 53 of the mantissa. */
- unsigned long long hi, lo;
- int ediff;
- union ibm_extended_long_double eldbl;
- eldbl.d = x;
- *exp = eldbl.ieee.exponent - IBM_EXTENDED_LONG_DOUBLE_BIAS;
-
- lo = ((long long)eldbl.ieee.mantissa2 << 32) | eldbl.ieee.mantissa3;
- hi = ((long long)eldbl.ieee.mantissa0 << 32) | eldbl.ieee.mantissa1;
- /* If the lower double is not a denomal or zero then set the hidden
- 53rd bit. */
- if (eldbl.ieee.exponent2 > 0x001)
- {
- lo |= (1ULL << 52);
- lo = lo << 7; /* pre-shift lo to match ieee854. */
- /* The lower double is normalized separately from the upper. We
- may need to adjust the lower mantissa to reflect this. */
- ediff = eldbl.ieee.exponent - eldbl.ieee.exponent2;
- if (ediff > 53)
- lo = lo >> (ediff-53);
- }
- hi |= (1ULL << 52);
-
- if ((eldbl.ieee.negative != eldbl.ieee.negative2)
- && ((eldbl.ieee.exponent2 != 0) && (lo != 0LL)))
- {
- hi--;
- lo = (1ULL << 60) - lo;
- if (hi < (1ULL << 52))
- {
- /* we have a borrow from the hidden bit, so shift left 1. */
- hi = (hi << 1) | (lo >> 59);
- lo = 0xfffffffffffffffLL & (lo << 1);
- *exp = *exp - 1;
- }
- }
- *lo64 = (hi << 60) | lo;
- *hi64 = hi >> 4;
-}
-
-static inline long double
-ldbl_insert_mantissa (int sign, int exp, int64_t hi64, u_int64_t lo64)
-{
- union ibm_extended_long_double u;
- unsigned long hidden2, lzcount;
- unsigned long long hi, lo;
-
- u.ieee.negative = sign;
- u.ieee.negative2 = sign;
- u.ieee.exponent = exp + IBM_EXTENDED_LONG_DOUBLE_BIAS;
- u.ieee.exponent2 = exp-53 + IBM_EXTENDED_LONG_DOUBLE_BIAS;
- /* Expect 113 bits (112 bits + hidden) right justified in two longs.
- The low order 53 bits (52 + hidden) go into the lower double */
- lo = (lo64 >> 7)& ((1ULL << 53) - 1);
- hidden2 = (lo64 >> 59) & 1ULL;
- /* The high order 53 bits (52 + hidden) go into the upper double */
- hi = (lo64 >> 60) & ((1ULL << 11) - 1);
- hi |= (hi64 << 4);
-
- if (lo != 0LL)
- {
- /* hidden2 bit of low double controls rounding of the high double.
- If hidden2 is '1' then round up hi and adjust lo (2nd mantissa)
- plus change the sign of the low double to compensate. */
- if (hidden2)
- {
- hi++;
- u.ieee.negative2 = !sign;
- lo = (1ULL << 53) - lo;
- }
- /* The hidden bit of the lo mantissa is zero so we need to
- normalize the it for the low double. Shift it left until the
- hidden bit is '1' then adjust the 2nd exponent accordingly. */
-
- if (sizeof (lo) == sizeof (long))
- lzcount = __builtin_clzl (lo);
- else if ((lo >> 32) != 0)
- lzcount = __builtin_clzl ((long) (lo >> 32));
- else
- lzcount = __builtin_clzl ((long) lo) + 32;
- lzcount = lzcount - 11;
- if (lzcount > 0)
- {
- int expnt2 = u.ieee.exponent2 - lzcount;
- if (expnt2 >= 1)
- {
- /* Not denormal. Normalize and set low exponent. */
- lo = lo << lzcount;
- u.ieee.exponent2 = expnt2;
- }
- else
- {
- /* Is denormal. */
- lo = lo << (lzcount + expnt2);
- u.ieee.exponent2 = 0;
- }
- }
- }
- else
- {
- u.ieee.negative2 = 0;
- u.ieee.exponent2 = 0;
- }
-
- u.ieee.mantissa3 = lo & ((1ULL << 32) - 1);
- u.ieee.mantissa2 = (lo >> 32) & ((1ULL << 20) - 1);
- u.ieee.mantissa1 = hi & ((1ULL << 32) - 1);
- u.ieee.mantissa0 = (hi >> 32) & ((1ULL << 20) - 1);
- return u.d;
-}
-
-/* gcc generates disgusting code to pack and unpack long doubles.
- This tells gcc that pack/unpack is really a nop. We use fr1/fr2
- because those are the regs used to pass/return a single
- long double arg. */
+/* GCC does not optimize the default ldbl_pack code to not spill register
+ in the stack. The following optimization tells gcc that pack/unpack
+ is really a nop. We use fr1/fr2 because those are the regs used to
+ pass/return a single long double arg. */
static inline long double
-ldbl_pack (double a, double aa)
+ldbl_pack_ppc (double a, double aa)
{
register long double x __asm__ ("fr1");
register double xh __asm__ ("fr1");
@@ -139,7 +19,7 @@ ldbl_pack (double a, double aa)
}
static inline void
-ldbl_unpack (long double l, double *a, double *aa)
+ldbl_unpack_ppc (long double l, double *a, double *aa)
{
register long double x __asm__ ("fr1");
register double xh __asm__ ("fr1");
@@ -150,40 +30,7 @@ ldbl_unpack (long double l, double *a, double *aa)
*aa = xl;
}
+#define ldbl_pack ldbl_pack_ppc
+#define ldbl_unpack ldbl_unpack_ppc
-/* Convert a finite long double to canonical form.
- Does not handle +/-Inf properly. */
-static inline void
-ldbl_canonicalize (double *a, double *aa)
-{
- double xh, xl;
-
- xh = *a + *aa;
- xl = (*a - xh) + *aa;
- *a = xh;
- *aa = xl;
-}
-
-/* Simple inline nearbyint (double) function .
- Only works in the default rounding mode
- but is useful in long double rounding functions. */
-static inline double
-ldbl_nearbyint (double a)
-{
- double two52 = 0x10000000000000LL;
-
- if (__builtin_expect ((__builtin_fabs (a) < two52), 1))
- {
- if (__builtin_expect ((a > 0.0), 1))
- {
- a += two52;
- a -= two52;
- }
- else if (__builtin_expect ((a < 0.0), 1))
- {
- a = two52 - a;
- a = -(a - two52);
- }
- }
- return a;
-}
+#include <sysdeps/ieee754/ldbl-128ibm/math_ldbl.h>
diff --git a/sysdeps/unix/sysv/linux/powerpc/Implies b/sysdeps/unix/sysv/linux/powerpc/Implies
deleted file mode 100644
index ff27cdb..0000000
--- a/sysdeps/unix/sysv/linux/powerpc/Implies
+++ /dev/null
@@ -1,4 +0,0 @@
-# Make sure these routines come before ldbl-opt.
-ieee754/ldbl-128ibm
-# These supply the ABI compatibility for when long double was double.
-ieee754/ldbl-opt
--
1.7.1