aboutsummaryrefslogtreecommitdiff
path: root/include/crypto/scatterwalk.h
diff options
context:
space:
mode:
authorMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>2008-08-16 03:39:26 -0400
committerIngo Molnar <mingo@elte.hu>2008-08-18 07:47:30 +0200
commit3c3b5c3b0bf798316a410e27e3d7e6f015663602 (patch)
treea774ddfd39dace35a85316ee69da4055f8ebde51 /include/crypto/scatterwalk.h
parent2fdc86901d2ab30a12402b46238951d2a7891590 (diff)
x86: correct register constraints for 64-bit atomic operations
x86_64 add/sub atomic ops does not seems to accept integer values bigger than 32 bits as immediates. Intel's add/sub documentation specifies they have to be passed as registers. The only operations in the x86-64 architecture which accept arbitrary 64-bit immediates is "movq" to any register; similarly, the only operation which accept arbitrary 64-bit displacement is "movabs" to or from al/ax/eax/rax. http://gcc.gnu.org/onlinedocs/gcc-4.3.0/gcc/Machine-Constraints.html states : e 32-bit signed integer constant, or a symbolic reference known to fit that range (for immediate operands in sign-extending x86-64 instructions). Z 32-bit unsigned integer constant, or a symbolic reference known to fit that range (for immediate operands in zero-extending x86-64 instructions). Since add/sub does sign extension, using the "e" constraint seems appropriate. It applies to 2.6.27-rc, 2.6.26, 2.6.25... Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/crypto/scatterwalk.h')
0 files changed, 0 insertions, 0 deletions