Volume 3: General-Purpose and System Instructions - Stanford ...

AMD64 Technology 24594 Rev. 3.10 February 2005temp_*_descNULL = 0x0000// temporary descriptor, with subfields:// if it points to a block of memory: sel base limit attr// if it’s a gate descriptor: sel offset segment attr// null selector is all zeros// V,Z,A,S are integer variables, assigned a value when an instruction begins// executing (they can be assigned a different value in the middle of an// instruction, if needed)V = 2 if OPERAND_SIZE=164 if OPERAND_SIZE=328 if OPERAND_SIZE=64Z = 2 if OPERAND_SIZE=164 if OPERAND_SIZE=324 if OPERAND_SIZE=64A = 2 if ADDRESS_SIZE=164 if ADDRESS_SIZE=328 if ADDRESS_SIZE=64S = 2 if STACK_SIZE=164 if STACK_SIZE=328 if STACK_SIZE=64/////////////////////////////////////////////////////////////////////////////////// Bit Range Inside a Register/////////////////////////////////////////////////////////////////////////////////temp_data.[X:Y]// Bit X through Y in temp_data, with the other bits// in the register masked off./////////////////////////////////////////////////////////////////////////////////// Moving Data From One Register To Another/////////////////////////////////////////////////////////////////////////////////temp_dest.b = temp_srctemp_dest.w = temp_srctemp_dest.d = temp_srctemp_dest.q = temp_srctemp_dest.v = temp_src// 1-byte move (copies lower 8 bits of temp_src to// temp_dest, preserving the upper 56 bits of temp_dest)// 2-byte move (copies lower 16 bits of temp_src to// temp_dest, preserving the upper 48 bits of temp_dest)// 4-byte move (copies lower 32 bits of temp_src to// temp_dest, and zeros out the upper 32 bits of temp_dest)// 8-byte move (copies all 64 bits of temp_src to// temp_dest)// 2-byte move if V=2,// 4-byte move if V=4,50 Chapter 2: Instruction Overview