Although I have to say my assembly code looks so different from anybody else's.
He also used plenty of raw assembly code in the beginning.
The 6502 assembly code was modified for 16-bit but otherwise mostly left intact.
There was very little assembly code used in the operating system.
The system was implemented largely in C with little assembly code.
Still at school, he learned how to program and he started to write a game in assembly code.
However, there is a finite number of register names that can be used in the assembly code.
Also the programming in assembly code was done by instructions.
High level code is easier to learn, program, read, and understand than assembly code.
Most early programming was performed in very amenable and complete assembly code.