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authorPaul Murphy <murphyp@linux.vnet.ibm.com>2016-06-10 14:50:32 -0500
committerTulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>2016-10-21 16:40:03 -0200
commit84d74e427a771906830800e574a72f8d25a954b8 (patch)
tree9574218747cd3569847507e3714e4ff38cbac897 /sysdeps/powerpc/fpu
parentb3918c44db615637b26d919ce599cd86592316b3 (diff)
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powerpc: Cleanup fenv_private.h
Some of the masks are wrong, and the naming is confusing.

There are two basic cases we really care about:

1. Stacking a new rounding mode when running certain
   sections of code, and pausing exception handling.

2. Likewise, but discarding any exceptions which occur
   while running under the new rounding mode.

libc_feholdexcept_setround_ppc_ctx has been removed as it basically
does the same thing as libc_feholdsetround_ppc_ctx but also clearing
any sticky bits.  The restore behavior is what differentiates these
two cases as the SET_RESTORE_ROUND{,_NOEX} macros will either merge
or discard all exceptions occurring during scope of their usage.

Likewise, there are a number of routines to swap, replace,
or merge FP environments.  This change reduces much of
the common and sometimes wrong code.

Tested on ppc64le, with results before and after.
Diffstat (limited to 'sysdeps/powerpc/fpu')
-rw-r--r--sysdeps/powerpc/fpu/fenv_private.h156
1 files changed, 53 insertions, 103 deletions
diff --git a/sysdeps/powerpc/fpu/fenv_private.h b/sysdeps/powerpc/fpu/fenv_private.h
index 02ac980909..ecc05bc937 100644
--- a/sysdeps/powerpc/fpu/fenv_private.h
+++ b/sysdeps/powerpc/fpu/fenv_private.h
@@ -23,56 +23,58 @@
 #include <fenv_libc.h>
 #include <fpu_control.h>
 
-#define _FPU_MASK_ALL (_FPU_MASK_ZM | _FPU_MASK_OM | _FPU_MASK_UM \
+/* Mask for the exception enable bits.  */
+#define _FPU_ALL_TRAPS (_FPU_MASK_ZM | _FPU_MASK_OM | _FPU_MASK_UM \
                       | _FPU_MASK_XM | _FPU_MASK_IM)
 
+/* Mask the rounding mode bits.  */
+#define _FPU_MASK_RN (~0x3)
+
 /* Mask everything but the rounding moded and non-IEEE arithmetic flags.  */
-#define _FPU_MASK_ROUNDING 0xffffffff00000007LL
+#define _FPU_MASK_NOT_RN_NI 0xffffffff00000007LL
 
 /* Mask restore rounding mode and exception enabled.  */
-#define _FPU_MASK_EXCEPT_ROUND 0xffffffff1fffff00LL
+#define _FPU_MASK_TRAPS_RN 0xffffffff1fffff00LL
 
 /* Mask exception enable but fraction rounded/inexact and FP result/CC
    bits.  */
-#define _FPU_MASK_FRAC_INEX_RET_CC 0x1ff80fff
+#define _FPU_MASK_FRAC_INEX_RET_CC 0xffffffff1ff80fff
 
 static __always_inline void
-libc_feholdexcept_ppc (fenv_t *envp)
+__libc_feholdbits_ppc (fenv_t *envp, unsigned long long mask,
+	unsigned long long bits)
 {
   fenv_union_t old, new;
 
   old.fenv = *envp = fegetenv_register ();
 
-  new.l = old.l & _FPU_MASK_ROUNDING;
+  new.l = (old.l & mask) | bits;
 
   /* If the old env had any enabled exceptions, then mask SIGFPE in the
      MSR FE0/FE1 bits.  This may allow the FPU to run faster because it
      always takes the default action and can not generate SIGFPE.  */
-  if ((old.l & _FPU_MASK_ALL) != 0)
+  if ((old.l & _FPU_ALL_TRAPS) != 0)
     (void) __fe_mask_env ();
 
   fesetenv_register (new.fenv);
 }
 
 static __always_inline void
-libc_fesetround_ppc (int r)
+libc_feholdexcept_ppc (fenv_t *envp)
 {
-  __fesetround_inline (r);
+  __libc_feholdbits_ppc (envp, _FPU_MASK_NOT_RN_NI, 0LL);
 }
 
 static __always_inline void
 libc_feholdexcept_setround_ppc (fenv_t *envp, int r)
 {
-  fenv_union_t old, new;
-
-  old.fenv = *envp = fegetenv_register ();
-
-  new.l = (old.l & _FPU_MASK_ROUNDING) | r;
-
-  if ((old.l & _FPU_MASK_ALL) != 0)
-    (void) __fe_mask_env ();
+  __libc_feholdbits_ppc (envp, _FPU_MASK_NOT_RN_NI & _FPU_MASK_RN, r);
+}
 
-  fesetenv_register (new.fenv);
+static __always_inline void
+libc_fesetround_ppc (int r)
+{
+  __fesetround_inline (r);
 }
 
 static __always_inline int
@@ -84,98 +86,67 @@ libc_fetestexcept_ppc (int e)
 }
 
 static __always_inline void
-libc_fesetenv_ppc (const fenv_t *envp)
+libc_feholdsetround_ppc (fenv_t *e, int r)
+{
+  __libc_feholdbits_ppc (e, _FPU_MASK_TRAPS_RN, r);
+}
+
+static __always_inline unsigned long long
+__libc_femergeenv_ppc (const fenv_t *envp, unsigned long long old_mask,
+	unsigned long long new_mask)
 {
   fenv_union_t old, new;
 
   new.fenv = *envp;
   old.fenv = fegetenv_register ();
 
+  /* Merge bits while masking unwanted bits from new and old env.  */
+  new.l = (old.l & old_mask) | (new.l & new_mask);
+
   /* If the old env has no enabled exceptions and the new env has any enabled
      exceptions, then unmask SIGFPE in the MSR FE0/FE1 bits.  This will put the
      hardware into "precise mode" and may cause the FPU to run slower on some
      hardware.  */
-  if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0)
+  if ((old.l & _FPU_ALL_TRAPS) == 0 && (new.l & _FPU_ALL_TRAPS) != 0)
     (void) __fe_nomask_env_priv ();
 
   /* If the old env had any enabled exceptions and the new env has no enabled
      exceptions, then mask SIGFPE in the MSR FE0/FE1 bits.  This may allow the
      FPU to run faster because it always takes the default action and can not
      generate SIGFPE.  */
-  if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0)
-    (void) __fe_mask_env ();
-
-  fesetenv_register (*envp);
-}
-
-static __always_inline int
-libc_feupdateenv_test_ppc (fenv_t *envp, int ex)
-{
-  fenv_union_t old, new;
-
-  new.fenv = *envp;
-  old.fenv = fegetenv_register ();
-
-  /* Restore rounding mode and exception enable from *envp and merge
-     exceptions.  Leave fraction rounded/inexact and FP result/CC bits
-     unchanged.  */
-  new.l = (old.l & _FPU_MASK_EXCEPT_ROUND)
-          | (new.l & _FPU_MASK_FRAC_INEX_RET_CC);
-
-  if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0)
-    (void) __fe_nomask_env_priv ();
-
-  if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0)
+  if ((old.l & _FPU_ALL_TRAPS) != 0 && (new.l & _FPU_ALL_TRAPS) == 0)
     (void) __fe_mask_env ();
 
+  /* Atomically enable and raise (if appropriate) exceptions set in `new'.  */
   fesetenv_register (new.fenv);
 
-  return old.l & ex;
+  return old.l;
 }
 
 static __always_inline void
-libc_feupdateenv_ppc (fenv_t *e)
+libc_fesetenv_ppc (const fenv_t *envp)
 {
-  libc_feupdateenv_test_ppc (e, 0);
+  /* Replace the entire environment.  */
+  __libc_femergeenv_ppc (envp, 0LL, -1LL);
 }
 
 static __always_inline void
-libc_feholdsetround_ppc (fenv_t *e, int r)
+libc_feresetround_ppc (fenv_t *envp)
 {
-  fenv_union_t old, new;
-
-  old.fenv = fegetenv_register ();
-  /* Clear current precision and set newer one.  */
-  new.l = (old.l & ~0x3 & ~_FPU_MASK_ALL) | r;
-  *e = old.fenv;
+  __libc_femergeenv_ppc (envp, _FPU_MASK_TRAPS_RN, _FPU_MASK_FRAC_INEX_RET_CC);
+}
 
-  if ((old.l & _FPU_MASK_ALL) != 0)
-    (void) __fe_mask_env ();
-  fesetenv_register (new.fenv);
+static __always_inline int
+libc_feupdateenv_test_ppc (fenv_t *envp, int ex)
+{
+  return __libc_femergeenv_ppc (envp, _FPU_MASK_TRAPS_RN,
+				_FPU_MASK_FRAC_INEX_RET_CC) & ex;
 }
 
 static __always_inline void
-libc_feresetround_ppc (fenv_t *envp)
+libc_feupdateenv_ppc (fenv_t *e)
 {
-  fenv_union_t old, new;
-
-  new.fenv = *envp;
-  old.fenv = fegetenv_register ();
-
-  /* Restore rounding mode and exception enable from *envp and merge
-     exceptions.  Leave fraction rounded/inexact and FP result/CC bits
-     unchanged.  */
-  new.l = (old.l & _FPU_MASK_EXCEPT_ROUND)
-          | (new.l & _FPU_MASK_FRAC_INEX_RET_CC);
-
-  if ((old.l & _FPU_MASK_ALL) == 0 && (new.l & _FPU_MASK_ALL) != 0)
-    (void) __fe_nomask_env_priv ();
-
-  if ((old.l & _FPU_MASK_ALL) != 0 && (new.l & _FPU_MASK_ALL) == 0)
-    (void) __fe_mask_env ();
-
-  /* Atomically enable and raise (if appropriate) exceptions set in `new'.  */
-  fesetenv_register (new.fenv);
+  libc_feupdateenv_test_ppc (e, 0);
 }
 
 #define libc_feholdexceptf           libc_feholdexcept_ppc
@@ -202,17 +173,18 @@ libc_feresetround_ppc (fenv_t *envp)
 #define HAVE_RM_CTX 1
 
 static __always_inline void
-libc_feholdexcept_setround_ppc_ctx (struct rm_ctx *ctx, int r)
+libc_feholdsetround_ppc_ctx (struct rm_ctx *ctx, int r)
 {
   fenv_union_t old, new;
 
   old.fenv = fegetenv_register ();
 
-  new.l = (old.l & _FPU_MASK_ROUNDING) | r;
+  new.l = (old.l & _FPU_MASK_TRAPS_RN) | r;
+
   ctx->env = old.fenv;
   if (__glibc_unlikely (new.l != old.l))
     {
-      if ((old.l & _FPU_MASK_ALL) != 0)
+      if ((old.l & _FPU_ALL_TRAPS) != 0)
 	(void) __fe_mask_env ();
       fesetenv_register (new.fenv);
       ctx->updated_status = true;
@@ -231,26 +203,7 @@ static __always_inline void
 libc_feupdateenv_ppc_ctx (struct rm_ctx *ctx)
 {
   if (__glibc_unlikely (ctx->updated_status))
-    libc_feupdateenv_test_ppc (&ctx->env, 0);
-}
-
-static __always_inline void
-libc_feholdsetround_ppc_ctx (struct rm_ctx *ctx, int r)
-{
-  fenv_union_t old, new;
-
-  old.fenv = fegetenv_register ();
-  new.l = (old.l & ~0x3 & ~_FPU_MASK_ALL) | r;
-  ctx->env = old.fenv;
-  if (__glibc_unlikely (new.l != old.l))
-    {
-      if ((old.l & _FPU_MASK_ALL) != 0)
-	(void) __fe_mask_env ();
-      fesetenv_register (new.fenv);
-      ctx->updated_status = true;
-    }
-  else
-    ctx->updated_status = false;
+    libc_feresetround_ppc (&ctx->env);
 }
 
 static __always_inline void
@@ -260,9 +213,6 @@ libc_feresetround_ppc_ctx (struct rm_ctx *ctx)
     libc_feresetround_ppc (&ctx->env);
 }
 
-#define libc_feholdexcept_setround_ctx   libc_feholdexcept_setround_ppc_ctx
-#define libc_feholdexcept_setroundf_ctx  libc_feholdexcept_setround_ppc_ctx
-#define libc_feholdexcept_setroundl_ctx  libc_feholdexcept_setround_ppc_ctx
 #define libc_fesetenv_ctx                libc_fesetenv_ppc_ctx
 #define libc_fesetenvf_ctx               libc_fesetenv_ppc_ctx
 #define libc_fesetenvl_ctx               libc_fesetenv_ppc_ctx