Subject: [Boost-commit] svn:boost r84816 - trunk/boost/atomic/detail
From: andrey.semashev_at_[hidden]
Date: 2013-06-17 16:07:13
Author: andysem
Date: 2013-06-17 16:07:13 EDT (Mon, 17 Jun 2013)
New Revision: 84816
URL: http://svn.boost.org/trac/boost/changeset/84816
Log:
Minor performance optimization and fixes of register constraints alternatives.
Text files modified:
trunk/boost/atomic/detail/gcc-x86.hpp | 55 +++++++++++++++++----------------------
trunk/boost/atomic/detail/windows.hpp | 7 ++--
2 files changed, 27 insertions(+), 35 deletions(-)
Modified: trunk/boost/atomic/detail/gcc-x86.hpp
==============================================================================
--- trunk/boost/atomic/detail/gcc-x86.hpp Mon Jun 17 15:17:53 2013 (r84815)
+++ trunk/boost/atomic/detail/gcc-x86.hpp 2013-06-17 16:07:13 EDT (Mon, 17 Jun 2013) (r84816)
@@ -1805,7 +1805,6 @@
return result;
#else
uint32_t scratch;
- T prev = expected;
/* Make sure ebx is saved and restored properly in case
this object is compiled as "position independent". Since
programmers on x86 tend to forget specifying -DPIC or
@@ -1825,14 +1824,13 @@
(
"movl %%ebx, %[scratch]\n\t"
"movl %[desired_lo], %%ebx\n\t"
- "lock; cmpxchg8b 0(%[dest])\n\t"
+ "lock; cmpxchg8b %[dest]\n\t"
"movl %[scratch], %%ebx\n\t"
"sete %[success]"
- : "+A,A,A,A,A,A,A,A" (prev), [scratch] "=m,m,m,m,m,m,m,m" (scratch), [success] "=q,m,q,m,q,m,q,m" (success)
- : [desired_lo] "S,S,D,D,m,m,m,m" ((uint32_t)desired), "c,c,c,c,c,c,c,c" ((uint32_t)(desired >> 32)), [dest] "D,D,S,S,D,D,S,S" (ptr)
+ : "+A,A,A,A,A,A" (expected), [dest] "+m,m,m,m,m,m" (*ptr), [scratch] "=m,m,m,m,m,m" (scratch), [success] "=q,m,q,m,q,m" (success)
+ : [desired_lo] "S,S,D,D,m,m" ((uint32_t)desired), "c,c,c,c,c,c" ((uint32_t)(desired >> 32))
: "memory", "cc"
);
- expected = prev;
return success;
#endif
}
@@ -1885,8 +1883,8 @@
"jne 1b\n\t"
"movl %[scratch], %%ebx"
: [scratch] "=m,m" (scratch)
- : [value_lo] "S,D" ((uint32_t)value), "c,c" ((uint32_t)(value >> 32)), [dest] "D,S" (ptr)
- : "memory", "cc", "eax", "edx"
+ : [value_lo] "a,a" ((uint32_t)value), "c,c" ((uint32_t)(value >> 32)), [dest] "D,S" (ptr)
+ : "memory", "cc", "edx"
);
}
}
@@ -1922,19 +1920,15 @@
else
{
// We don't care for comparison result here; the previous value will be stored into value anyway.
- uint32_t scratch;
+ // Also we don't care for ebx and ecx values, they just have to be equal to eax and edx before cmpxchg8b.
__asm__ __volatile__
(
- "movl %%ebx, %[scratch]\n\t"
- "xorl %%eax, %%eax\n\t"
- "xorl %%ebx, %%ebx\n\t"
- "xorl %%ecx, %%ecx\n\t"
- "xorl %%edx, %%edx\n\t"
- "lock; cmpxchg8b 0(%[dest])\n\t"
- "movl %[scratch], %%ebx"
- : "=A,A" (value), [scratch] "=m,m" (scratch)
- : [dest] "D,S" (ptr)
- : "cc", "ecx"
+ "movl %%ebx, %%eax\n\t"
+ "movl %%ecx, %%edx\n\t"
+ "lock; cmpxchg8b %[dest]"
+ : "=&A" (value)
+ : [dest] "m" (*ptr)
+ : "cc"
);
}
@@ -1953,10 +1947,10 @@
bool success;
__asm__ __volatile__
(
- "lock; cmpxchg16b 0(%[dest])\n\t"
+ "lock; cmpxchg16b %[dest]\n\t"
"sete %[success]"
- : "+A,A,A,A" (expected), [success] "=q,m,q,m" (success)
- : "b,b,b,b" (p_desired[0]), "c,c,c,c" (p_desired[1]), [dest] "D,D,S,S" (ptr)
+ : "+A,A" (expected), [dest] "+m,m" (*ptr), [success] "=q,m" (success)
+ : "b,b" (p_desired[0]), "c,c" (p_desired[1])
: "memory", "cc"
);
return success;
@@ -1973,9 +1967,9 @@
"movq 8(%[dest]), %%rdx\n\t"
".align 16\n\t"
"1: lock; cmpxchg16b 0(%[dest])\n\t"
- "jne 1b\n\t"
+ "jne 1b"
:
- : "b" (p_value[0]), "c" (p_value[1]), [dest] "D,S" (ptr)
+ : "b" (p_value[0]), "c" (p_value[1]), [dest] "r" (ptr)
: "memory", "cc", "rax", "rdx"
);
}
@@ -1987,16 +1981,15 @@
T value;
// We don't care for comparison result here; the previous value will be stored into value anyway.
+ // Also we don't care for rbx and rcx values, they just have to be equal to rax and rdx before cmpxchg16b.
__asm__ __volatile__
(
- "xorq %%rax, %%rax\n\t"
- "xorq %%rbx, %%rbx\n\t"
- "xorq %%rcx, %%rcx\n\t"
- "xorq %%rdx, %%rdx\n\t"
- "lock; cmpxchg16b 0(%[dest])\n\t"
- : "=A,A" (value)
- : [dest] "D,S" (ptr)
- : "cc", "rbx", "rcx"
+ "movq %%rbx, %%rax\n\t"
+ "movq %%rcx, %%rdx\n\t"
+ "lock; cmpxchg16b %[dest]"
+ : "=&A" (value)
+ : [dest] "m" (*ptr)
+ : "cc"
);
return value;
Modified: trunk/boost/atomic/detail/windows.hpp
==============================================================================
--- trunk/boost/atomic/detail/windows.hpp Mon Jun 17 15:17:53 2013 (r84815)
+++ trunk/boost/atomic/detail/windows.hpp 2013-06-17 16:07:13 EDT (Mon, 17 Jun 2013) (r84816)
@@ -1644,13 +1644,12 @@
else
{
// We don't care for comparison result here; the previous value will be stored into value anyway.
+ // Also we don't care for ebx and ecx values, they just have to be equal to eax and edx before cmpxchg8b.
__asm
{
mov edi, p
- xor ebx, ebx
- xor ecx, ecx
- xor eax, eax
- xor edx, edx
+ mov eax, ebx
+ mov edx, ecx
lock cmpxchg8b qword ptr [edi]
mov dword ptr [value], eax
mov dword ptr [value + 4], edx