While there were macro assemblers, all I did use was the built-in machine monitor, which was basically a system provided debugger. But you could assemble single

While there were macro assemblers, all I did use was the built-in machine monitor, which was basically a system provided debugger. But you could assemble single mnemonics into a memory location of your choosing, so I would put programs together directly in memory, one instruction at a time. That required counting their length as well, and doesn't support any constructs that span multiple instructions, like macros or variables... I knew variables already from commodore Basic, which i learned first. But there was no concept of pointers, direct interaction with memory happened via peek and poke, and the adress space was so small, you just chose an adress where to put your stuff and worked with offsets. It is worth remembering that on these old machines there was no OS managed memory allocation... So there was much less need to work with adresses unknown at "compile time".