SaM Symbol Table

(CORE/SYMBOLTABLE.JAVA,

CORE/SAMSYMBOLTABLE.JAVA)

A SaM program supports the use of labels, defined as a string ending with ':', such as "ThisIsALabel:" Jump instructions can then take the name of such a label, and jump to that address in the program. The SaM Symbol Table is responsible for mapping labels (symbols) to addresses, and vice versa. It is implemented by using two hash tables, enabling a search using a symbol, or a search using an address.

The SaM core package will support multiple labels per address. Unfortunately, as of SaM 2.3, the GUI does not handle multiple stacked labels quite properly, and simplifies them down to one. This is nontrivial to fix, but will be corrected in a future release.

The symbol table provides the following methods:

• void add(String symbol, int address) - add a symbol with the specified address
• String resolveSymbol(int address) - return the symbol for the given address
• Collection<String> resolveSymbols(int address) -return all symbols for the given address
• int resolveAddress(String label) - return the address for the given symbol
• Collection<String> getSymbols() - return a collection of all symbols
• String toString() - return a string representation of this table