Compilers: Principles and Practice by Pearson

438 Appendix B

3. If a forward reference is found, add a node to a ‘ToDereference’ array of linked list, where

each array element has a structure:

<symbol> <address> <ptr> --> <obj code pos #1> <obj code pos #2> ...

When a forward reference is not yet defined, <address> is zero. When it gets defined later

in the code, the assembler inserts its address value at the code positions according to the

link list. This assumes that either the complete object code is held in memory or a “random-

load” loader is required.

Such an one-pass assembler was relevant when in old days the secondary storage units were slow and

expensive. Sometimes it is used ...