LinuxQuestions.org - Nasm struct usage

I defined a struct in .data segment:

Code:

section .data

    struc tree_node

        .left_child resd 1            ; reserve 1 doubleword

        .node_data resb 1              ; reserve 1 byte

        .right_child resd 1            ; reserve 1 doubleword

    endstruc

    

    node_ptr:

    istruc tree_node

        at tree_node.left_child, dd 1

        at tree_node.node_data, db 1

        at tree_node.right_child, dd 1

    iend

I want to create left and right child of node_ptr as in C and modify it when necessary.