commit e5e0d9a4f632735cf3bb440eecb5caee5eea44c1
Author: Ian Bolton <ian.bolton@arm.com>
Date: Thu Apr 24 07:15:33 2014 +0100
[AArch64] Suppress unnecessary FPSR and FPCR writes.
diff --git a/ports/sysdeps/aarch64/fpu/fclrexcpt.c b/ports/sysdeps/aarch64/fpu/fclrexcpt.c
index 531269f..b24f0ff 100644
--- a/ports/sysdeps/aarch64/fpu/fclrexcpt.c
+++ b/ports/sysdeps/aarch64/fpu/fclrexcpt.c
@@ -23,13 +23,15 @@ int
feclearexcept (int excepts)
{
fpu_fpsr_t fpsr;
+ fpu_fpsr_t fpsr_new;
excepts &= FE_ALL_EXCEPT;
_FPU_GETFPSR (fpsr);
- fpsr = (fpsr & ~FE_ALL_EXCEPT) | (fpsr & FE_ALL_EXCEPT & ~excepts);
+ fpsr_new = (fpsr & ~FE_ALL_EXCEPT) | (fpsr & FE_ALL_EXCEPT & ~excepts);
- _FPU_SETFPSR (fpsr);
+ if (fpsr != fpsr_new)
+ _FPU_SETFPSR (fpsr_new);
return 0;
}
diff --git a/ports/sysdeps/aarch64/fpu/fedisblxcpt.c b/ports/sysdeps/aarch64/fpu/fedisblxcpt.c
index 719d52f..c43335c 100644
--- a/ports/sysdeps/aarch64/fpu/fedisblxcpt.c
+++ b/ports/sysdeps/aarch64/fpu/fedisblxcpt.c
@@ -23,6 +23,7 @@ int
fedisableexcept (int excepts)
{
fpu_control_t fpcr;
+ fpu_control_t fpcr_new;
int original_excepts;
_FPU_GETCW (fpcr);
@@ -31,9 +32,10 @@ fedisableexcept (int excepts)
excepts &= FE_ALL_EXCEPT;
- fpcr &= ~(excepts << FE_EXCEPT_SHIFT);
+ fpcr_new = fpcr & ~(excepts << FE_EXCEPT_SHIFT);
- _FPU_SETCW (fpcr);
+ if (fpcr != fpcr_new)
+ _FPU_SETCW (fpcr_new);
return original_excepts;
}
diff --git a/ports/sysdeps/aarch64/fpu/feenablxcpt.c b/ports/sysdeps/aarch64/fpu/feenablxcpt.c
index 07a4bbb..70e413c 100644
--- a/ports/sysdeps/aarch64/fpu/feenablxcpt.c
+++ b/ports/sysdeps/aarch64/fpu/feenablxcpt.c
@@ -23,6 +23,7 @@ int
feenableexcept (int excepts)
{
fpu_control_t fpcr;
+ fpu_control_t fpcr_new;
int original_excepts;
_FPU_GETCW (fpcr);
@@ -31,9 +32,10 @@ feenableexcept (int excepts)
excepts &= FE_ALL_EXCEPT;
- fpcr |= (excepts << FE_EXCEPT_SHIFT);
+ fpcr_new = fpcr | (excepts << FE_EXCEPT_SHIFT);
- _FPU_SETCW (fpcr);
+ if (fpcr != fpcr_new)
+ _FPU_SETCW (fpcr_new);
/* Trapping exceptions are optional in AArch64 the relevant enable
bits in FPCR are RES0 hence the absence of support can be
diff --git a/ports/sysdeps/aarch64/fpu/feholdexcpt.c b/ports/sysdeps/aarch64/fpu/feholdexcpt.c
index 0514ac1..973ba4a 100644
--- a/ports/sysdeps/aarch64/fpu/feholdexcpt.c
+++ b/ports/sysdeps/aarch64/fpu/feholdexcpt.c
@@ -22,8 +22,10 @@
int
feholdexcept (fenv_t *envp)
{
- fpu_fpsr_t fpsr;
fpu_control_t fpcr;
+ fpu_control_t fpcr_new;
+ fpu_fpsr_t fpsr;
+ fpu_fpsr_t fpsr_new;
_FPU_GETCW (fpcr);
envp->__fpcr = fpcr;
@@ -32,14 +34,16 @@ feholdexcept (fenv_t *envp)
envp->__fpsr = fpsr;
/* Now set all exceptions to non-stop. */
- fpcr &= ~(FE_ALL_EXCEPT << FE_EXCEPT_SHIFT);
+ fpcr_new = fpcr & ~(FE_ALL_EXCEPT << FE_EXCEPT_SHIFT);
/* And clear all exception flags. */
- fpsr &= ~FE_ALL_EXCEPT;
+ fpsr_new = fpsr & ~FE_ALL_EXCEPT;
- _FPU_SETFPSR (fpsr);
+ if (fpsr != fpsr_new)
+ _FPU_SETFPSR (fpsr_new);
- _FPU_SETCW (fpcr);
+ if (fpcr != fpcr_new)
+ _FPU_SETCW (fpcr_new);
return 0;
}
diff --git a/ports/sysdeps/aarch64/fpu/fesetenv.c b/ports/sysdeps/aarch64/fpu/fesetenv.c
index a2434e3..30193e9 100644
--- a/ports/sysdeps/aarch64/fpu/fesetenv.c
+++ b/ports/sysdeps/aarch64/fpu/fesetenv.c
@@ -23,34 +23,38 @@ int
fesetenv (const fenv_t *envp)
{
fpu_control_t fpcr;
- fpu_fpsr_t fpsr;
+ fpu_control_t fpcr_new;
fpu_control_t updated_fpcr;
+ fpu_fpsr_t fpsr;
+ fpu_fpsr_t fpsr_new;
_FPU_GETCW (fpcr);
_FPU_GETFPSR (fpsr);
- fpcr &= _FPU_RESERVED;
- fpsr &= _FPU_FPSR_RESERVED;
+ fpcr_new = fpcr & _FPU_RESERVED;
+ fpsr_new = fpsr & _FPU_FPSR_RESERVED;
if (envp == FE_DFL_ENV)
{
- fpcr |= _FPU_DEFAULT;
- fpsr |= _FPU_FPSR_DEFAULT;
+ fpcr_new |= _FPU_DEFAULT;
+ fpsr_new |= _FPU_FPSR_DEFAULT;
}
else if (envp == FE_NOMASK_ENV)
{
- fpcr |= _FPU_FPCR_IEEE;
- fpsr |= _FPU_FPSR_IEEE;
+ fpcr_new |= _FPU_FPCR_IEEE;
+ fpsr_new |= _FPU_FPSR_IEEE;
}
else
{
- fpcr |= envp->__fpcr & ~_FPU_RESERVED;
- fpsr |= envp->__fpsr & ~_FPU_FPSR_RESERVED;
+ fpcr_new |= envp->__fpcr & ~_FPU_RESERVED;
+ fpsr_new |= envp->__fpsr & ~_FPU_FPSR_RESERVED;
}
- _FPU_SETFPSR (fpsr);
+ if (fpsr != fpsr_new)
+ _FPU_SETFPSR (fpsr_new);
- _FPU_SETCW (fpcr);
+ if (fpcr != fpcr_new)
+ _FPU_SETCW (fpcr_new);
/* Trapping exceptions are optional in AArch64 the relevant enable
bits in FPCR are RES0 hence the absence of support can be
@@ -58,7 +62,7 @@ fesetenv (const fenv_t *envp)
value. */
_FPU_GETCW (updated_fpcr);
- if ((updated_fpcr & fpcr) != fpcr)
+ if ((updated_fpcr & fpcr_new) != fpcr_new)
return 1;
return 0;
diff --git a/ports/sysdeps/aarch64/fpu/fesetround.c b/ports/sysdeps/aarch64/fpu/fesetround.c
index 40a05f6..225096a 100644
--- a/ports/sysdeps/aarch64/fpu/fesetround.c
+++ b/ports/sysdeps/aarch64/fpu/fesetround.c
@@ -23,6 +23,7 @@ int
fesetround (int round)
{
fpu_control_t fpcr;
+ fpu_control_t fpcr_new;
switch (round)
{
@@ -31,9 +32,10 @@ fesetround (int round)
case FE_DOWNWARD:
case FE_TOWARDZERO:
_FPU_GETCW (fpcr);
- fpcr = (fpcr & ~FE_TOWARDZERO) | round;
+ fpcr_new = (fpcr & ~FE_TOWARDZERO) | round;
- _FPU_SETCW (fpcr);
+ if (fpcr != fpcr_new)
+ _FPU_SETCW (fpcr_new);
return 0;
default:
diff --git a/ports/sysdeps/aarch64/fpu/fsetexcptflg.c b/ports/sysdeps/aarch64/fpu/fsetexcptflg.c
index 49cd1e4..60bb1c9 100644
--- a/ports/sysdeps/aarch64/fpu/fsetexcptflg.c
+++ b/ports/sysdeps/aarch64/fpu/fsetexcptflg.c
@@ -24,16 +24,18 @@ int
fesetexceptflag (const fexcept_t *flagp, int excepts)
{
fpu_fpsr_t fpsr;
+ fpu_fpsr_t fpsr_new;
/* Get the current environment. */
_FPU_GETFPSR (fpsr);
/* Set the desired exception mask. */
- fpsr &= ~(excepts & FE_ALL_EXCEPT);
- fpsr |= (*flagp & excepts & FE_ALL_EXCEPT);
+ fpsr_new = fpsr & ~(excepts & FE_ALL_EXCEPT);
+ fpsr_new |= (*flagp & excepts & FE_ALL_EXCEPT);
/* Save state back to the FPU. */
- _FPU_SETFPSR (fpsr);
+ if (fpsr != fpsr_new)
+ _FPU_SETFPSR (fpsr_new);
return 0;
}