A Use for the USR Command

The S-C Assembler II Version 4.0 has one user-programmable command, called "USR".  (The Quick Reference Card spells it erroneously "USEr".)  One good use for it is to re-print the current symbol table.

After an assembly, if the listing was not printed, it is often desirable to be able to see what the spelling or value of a symbol or group of symbols is.  If the VAL command is not enough for you, then the following steps will set up the USR command to re-list the symbol table on the screen.  And, if your printer is selected, it will also print there.

Get into the assembler, by using BRUN ASMDISK 4.0 from either Applesoft or Integer BASIC.  Type "$1E4EL" after the prompt.  The first two lines listed should be "LDY #$02" and "STY $E1".  If they are not, you have a different version.  (It may still be version 4.0, but slightly different.)  The "LDY#$02" line is the first instruction of the symbol table printing subroutine.

Patch the USR vector by typing "$1007:4E 1E", and then BSAVE the result like this:

       :BSAVE ASMDISK 4.0 (WITH USR),A$1000,L$14FB

This new version, whenever you type "USR", will print out the current symbol table.  It will look exactly the same as the symbol table pritned out at the end of an assembly.

