Modern Computer Architecture and Organization, by Jim Ledin. Published by Packt Publishing.
Write 6502 assembly code to subtract two 16-bit values in a manner similar to Exercise 4. Test with $0001-$0000, $0001-$0001, $0100-$00FF, and $0000-$0001. What is the result for $0000-$0001?
See the 6502 assembly file Ex__5_16_bit_subtraction.asm for the 16-bit subtraction code.
Try running this code at https://skilldrick.github.io/easy6502/