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Diffstat (limited to 'externals/mysql/my_atomic.h')
| -rw-r--r-- | externals/mysql/my_atomic.h | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/externals/mysql/my_atomic.h b/externals/mysql/my_atomic.h new file mode 100644 index 00000000000..40b8895657d --- /dev/null +++ b/externals/mysql/my_atomic.h @@ -0,0 +1,254 @@ +/* Copyright (C) 2006 MySQL AB + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ + +/* + This header defines five atomic operations: + + my_atomic_add#(&var, what) + add 'what' to *var, and return the old value of *var + + my_atomic_fas#(&var, what) + 'Fetch And Store' + store 'what' in *var, and return the old value of *var + + my_atomic_cas#(&var, &old, new) + 'Compare And Swap' + if *var is equal to *old, then store 'new' in *var, and return TRUE + otherwise store *var in *old, and return FALSE + + my_atomic_load#(&var) + return *var + + my_atomic_store#(&var, what) + store 'what' in *var + + '#' is substituted by a size suffix - 8, 16, 32, or ptr + (e.g. my_atomic_add8, my_atomic_fas32, my_atomic_casptr). + + NOTE This operations are not always atomic, so they always must be + enclosed in my_atomic_rwlock_rdlock(lock)/my_atomic_rwlock_rdunlock(lock) + or my_atomic_rwlock_wrlock(lock)/my_atomic_rwlock_wrunlock(lock). + Hint: if a code block makes intensive use of atomic ops, it make sense + to take/release rwlock once for the whole block, not for every statement. + + On architectures where these operations are really atomic, rwlocks will + be optimized away. + 8- and 16-bit atomics aren't implemented for windows (see generic-msvc.h), + but can be added, if necessary. +*/ + +#ifndef my_atomic_rwlock_init + +#define intptr void * + +#ifndef MY_ATOMIC_MODE_RWLOCKS +#include "atomic/nolock.h" +#endif + +#ifndef make_atomic_cas_body +/* nolock.h was not able to generate even a CAS function, fall back */ +#include "atomic/rwlock.h" +#else +/* define missing functions by using the already generated ones */ +#ifndef make_atomic_add_body +#define make_atomic_add_body(S) \ + int ## S tmp=*a; \ + while (!my_atomic_cas ## S(a, &tmp, tmp+v)); \ + v=tmp; +#endif +#ifndef make_atomic_fas_body +#define make_atomic_fas_body(S) \ + int ## S tmp=*a; \ + while (!my_atomic_cas ## S(a, &tmp, v)); \ + v=tmp; +#endif +#ifndef make_atomic_load_body +#define make_atomic_load_body(S) \ + ret= 0; /* avoid compiler warning */ \ + (void)(my_atomic_cas ## S(a, &ret, ret)); +#endif +#ifndef make_atomic_store_body +#define make_atomic_store_body(S) \ + (void)(my_atomic_fas ## S (a, v)); +#endif +#endif + +/* + transparent_union doesn't work in g++ + Bug ? + + Darwin's gcc doesn't want to put pointers in a transparent_union + when built with -arch ppc64. Complains: + warning: 'transparent_union' attribute ignored +*/ +#if defined(__GNUC__) && !defined(__cplusplus) && \ + ! (defined(__APPLE__) && defined(_ARCH_PPC64)) +/* + we want to be able to use my_atomic_xxx functions with + both signed and unsigned integers. But gcc will issue a warning + "passing arg N of `my_atomic_XXX' as [un]signed due to prototype" + if the signedness of the argument doesn't match the prototype, or + "pointer targets in passing argument N of my_atomic_XXX differ in signedness" + if int* is used where uint* is expected (or vice versa). + Let's shut these warnings up +*/ +#define make_transparent_unions(S) \ + typedef union { \ + int ## S i; \ + uint ## S u; \ + } U_ ## S __attribute__ ((transparent_union)); \ + typedef union { \ + int ## S volatile *i; \ + uint ## S volatile *u; \ + } Uv_ ## S __attribute__ ((transparent_union)); +#define uintptr intptr +make_transparent_unions(8) +make_transparent_unions(16) +make_transparent_unions(32) +make_transparent_unions(ptr) +#undef uintptr +#undef make_transparent_unions +#define a U_a.i +#define cmp U_cmp.i +#define v U_v.i +#define set U_set.i +#else +#define U_32 int32 +#define U_ptr intptr +#define Uv_32 int32 +#define Uv_ptr intptr +#define U_a volatile *a +#define U_cmp *cmp +#define U_v v +#define U_set set +#endif /* __GCC__ transparent_union magic */ + +#ifdef HAVE_INLINE + +#define make_atomic_cas(S) \ +STATIC_INLINE int my_atomic_cas ## S(Uv_ ## S U_a, \ + Uv_ ## S U_cmp, U_ ## S U_set) \ +{ \ + int8 ret; \ + make_atomic_cas_body(S); \ + return ret; \ +} + +#define make_atomic_add(S) \ +STATIC_INLINE int ## S my_atomic_add ## S( \ + Uv_ ## S U_a, U_ ## S U_v) \ +{ \ + make_atomic_add_body(S); \ + return v; \ +} + +#define make_atomic_fas(S) \ +STATIC_INLINE int ## S my_atomic_fas ## S( \ + Uv_ ## S U_a, U_ ## S U_v) \ +{ \ + make_atomic_fas_body(S); \ + return v; \ +} + +#define make_atomic_load(S) \ +STATIC_INLINE int ## S my_atomic_load ## S(Uv_ ## S U_a) \ +{ \ + int ## S ret; \ + make_atomic_load_body(S); \ + return ret; \ +} + +#define make_atomic_store(S) \ +STATIC_INLINE void my_atomic_store ## S( \ + Uv_ ## S U_a, U_ ## S U_v) \ +{ \ + make_atomic_store_body(S); \ +} + +#else /* no inline functions */ + +#define make_atomic_add(S) \ +extern int ## S my_atomic_add ## S(Uv_ ## S U_a, U_ ## S U_v); + +#define make_atomic_fas(S) \ +extern int ## S my_atomic_fas ## S(Uv_ ## S U_a, U_ ## S U_v); + +#define make_atomic_cas(S) \ +extern int my_atomic_cas ## S(Uv_ ## S U_a, Uv_ ## S U_cmp, U_ ## S U_set); + +#define make_atomic_load(S) \ +extern int ## S my_atomic_load ## S(Uv_ ## S U_a); + +#define make_atomic_store(S) \ +extern void my_atomic_store ## S(Uv_ ## S U_a, U_ ## S U_v); + +#endif + +make_atomic_cas(32) +make_atomic_cas(ptr) + +make_atomic_add(32) + +make_atomic_load(32) +make_atomic_load(ptr) + +make_atomic_fas(32) +make_atomic_fas(ptr) + +make_atomic_store(32) +make_atomic_store(ptr) + +#ifdef _atomic_h_cleanup_ +#include _atomic_h_cleanup_ +#undef _atomic_h_cleanup_ +#endif + +#undef U_32 +#undef U_ptr +#undef a +#undef cmp +#undef v +#undef set +#undef U_a +#undef U_cmp +#undef U_v +#undef U_set +#undef make_atomic_add +#undef make_atomic_cas +#undef make_atomic_load +#undef make_atomic_store +#undef make_atomic_fas +#undef make_atomic_add_body +#undef make_atomic_cas_body +#undef make_atomic_load_body +#undef make_atomic_store_body +#undef make_atomic_fas_body +#undef intptr + +/* + the macro below defines (as an expression) the code that + will be run in spin-loops. Intel manuals recummend to have PAUSE there. + It is expected to be defined in include/atomic/ *.h files +*/ +#ifndef LF_BACKOFF +#define LF_BACKOFF (1) +#endif + +#define MY_ATOMIC_OK 0 +#define MY_ATOMIC_NOT_1CPU 1 +extern int my_atomic_initialize(); + +#endif + |