This atomically test's and clear's a bit.
Change in V3:
- adding IA32 support. (not yet reviewed)
both XenBusDxe/Ia32/TestAndClearBit.{S,asm} are new
Change in V2:
- Adding .asm version
- Comment the function
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16266
6f19259b-4bc3-4df7-8a09-
765794883524
--- /dev/null
+# INT32\r
+# EFIAPI\r
+# TestAndClearBit (\r
+# IN INT32 Bit,\r
+# IN volatile VOID* Address\r
+# );\r
+ASM_GLOBAL ASM_PFX(TestAndClearBit)\r
+ASM_PFX(TestAndClearBit):\r
+ mov 4(%esp), %ecx\r
+ mov 8(%esp), %edx\r
+ lock btrl %ecx, (%edx)\r
+ sbbl %eax, %eax\r
+ ret\r
--- /dev/null
+.code\r
+\r
+; INT32\r
+; EFIAPI\r
+; TestAndClearBit (\r
+; IN INT32 Bit,\r
+; IN volatile VOID* Address\r
+; );\r
+TestAndClearBit PROC\r
+ mov ecx, [esp + 4]\r
+ mov edx, [esp + 8]\r
+ lock btr [edx], ecx\r
+ sbb eax, eax\r
+ ret\r
+TestAndClearBit ENDP\r
+\r
+END\r
--- /dev/null
+# INT32\r
+# EFIAPI\r
+# TestAndClearBit (\r
+# IN INT32 Bit, // rcx\r
+# IN volatile VOID* Address // rdx\r
+# );\r
+ASM_GLOBAL ASM_PFX(TestAndClearBit)\r
+ASM_PFX(TestAndClearBit):\r
+ lock\r
+ btrl %ecx, (%rdx)\r
+ sbbl %eax, %eax\r
+ ret\r
--- /dev/null
+.code\r
+\r
+; INT32\r
+; EFIAPI\r
+; TestAndClearBit (\r
+; IN INT32 Bit, // rcx\r
+; IN volatile VOID* Address // rdx\r
+; );\r
+TestAndClearBit PROC\r
+ lock\r
+ btr [rdx], ecx\r
+ sbb eax, eax\r
+ ret\r
+TestAndClearBit ENDP\r
+\r
+END\r
shared_info_t *SharedInfo;\r
};\r
\r
+/*\r
+ * Helpers\r
+ */\r
+\r
+/**\r
+ Atomically test and clear a bit.\r
+\r
+ @param Bit Bit index to test in *Address\r
+ @param Address The Address to the buffer that contain the bit to test.\r
+\r
+ @return Value of the Bit before it was cleared.\r
+**/\r
+INT32\r
+EFIAPI\r
+TestAndClearBit (\r
+ IN INT32 Bit,\r
+ IN volatile VOID *Address\r
+ );\r
+\r
#endif\r
Ia32/hypercall.asm\r
Ia32/InterlockedCompareExchange16.S\r
Ia32/InterlockedCompareExchange16.asm\r
+ Ia32/TestAndClearBit.S\r
+ Ia32/TestAndClearBit.asm\r
\r
[Sources.X64]\r
X64/hypercall.S\r
X64/hypercall.asm\r
X64/InterlockedCompareExchange16.S\r
X64/InterlockedCompareExchange16.asm\r
+ X64/TestAndClearBit.S\r
+ X64/TestAndClearBit.asm\r
\r
[LibraryClasses]\r
UefiDriverEntryPoint\r