I'm not an x86-64 expert, but it implies from intel docs that 64 bit immediate values are supported only for the MOV instruction:
http://www.intel.com/assets/pdf/manual/253666.pdf ------------------- 2.2.1.5 Immediates In 64-bit mode, the typical size of immediate operands remains 32 bits. When the operand size is 64 bits, the processor sign-extends all immediates to 64 bits prior to their use. Support for 64-bit immediate operands is accomplished by expanding the semantics of the existing move (MOV reg, imm16/32) instructions. These instructions (opcodes B8H – BFH) move 16-bits or 32-bits of immediate data (depending on the effective operand size) into a GPR. When the effective operand size is 64 bits, these instructions can be used to load an immediate into a GPR. A REX prefix is needed to override the 32-bit default operand size to a 64-bit operand size. For example: 48 B8 8877665544332211 MOV RAX,1122334455667788H ------------------- Udi On Fri, Feb 4, 2011 at 9:02 AM, Gilboa Davara <gilb...@gmail.com> wrote: > Hello all, > > I'm trying to pass the following command inside GCC inline assembly > block (which targets x86_64 kernel and usermode). > > asm volatile > { > ... > "andq $0x5555555555555555, %%r11 ;" > ... > } > > And getting the following error: > 'Error: operand type mismatch for `and'' > > The 32bit version of this code (which uses $0x55555555 constant value) > works just fine. > Shaving ~4 digits off the constant value, seems to working as well. > > So, any idea how I can force-feed 64bit hex values into 64bit inline > assembly? > > - Gilboa > > > _______________________________________________ > Linux-il mailing list > Linux-il@cs.huji.ac.il > http://mailman.cs.huji.ac.il/mailman/listinfo/linux-il >
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