Double Density Histograms
John Race · 1981
This short program is one example of the use of ‘double density plots’ on the PET screen, which in turn relies on a program written for the 6502 microprocessor in Assembler. In Superlife, the machine code program was hand-coded: here, it was written using mnemonic operators like ADC (for Add with Carry) instead of hexadecimal codes like 6D, and symbolic names like FRED instead of hexadecimal addresses like E56A, relying on an Assembler to translate from the meaningful to the obscure.