[JoBullet]

You could perhaps get "op_const_s"(the opcode before op_sysreq_d, note that AMX_NO_PACKED_OPC is undefined, thus not accounted for) opcode pointer and increment it by 4 (because we can assert that amx_opcodelist structure won't change and AMX_NO_PACKED_OPC was not defined at time of compiling compiler)
thus getting us address of op_sysreq_d.