I believe 6502 instruction set is a good first assembly language

I started with BASIC on a Vic 20 in 1979 in a computer class for kids. Then I got my own Atari 400 at home, so I learned BASIC on that. Then around 1984 I got a Commodore 64 and it was amazing. I quickly got past the BASIC part of the C64 manual and in the back of the manual they had a memory map, all the hardware registers for all the chips, and then all the 6502/6510 opcodes. There was even an entire schematic for the C64 in the back of the book as a fold-out poster. 14 year old me was hooked. I got into assembly when I was about 15 and never looked back to BASIC. I wrote a lot of assembly code for many years, creating "crack intros" for cracking groups and demos on the C64. I then moved on to Amiga and 68000 assembly, and I even got into SNES 65C816 (16 bit version of 6502) assembly coding using a 30th generation photocopy of the pirated SNES developer manual and a floppy disk game copier, which also had a parallel port that I managed to connect to my Amiga and use that as the development system uploading the compiled program to the SNES via parallel port. I would make "crack intros" for SNES games being traded on pirate BBS's. It was a lot of fun. Many years later, I'm still doing some 8-bit assembly code for microcontroller projects where I'm trying to use the smallest possible CPU to do interesting things. Everything I learned about Assembly on the C64 still applies to the modern microcontrollers (PIC/AVR) that I use today.

In so many of these years I had not learned C. I went from assembly to scripting languages, and was a very early adopter of Javascript since the same month it first came out. Only in the last 10 years have I learned C, and it was so easy! After learning Assembly and Javascript, C was right in the middle.

I've programmed in over a dozen languages through the years, but I'm really happy with Assembly, C, and Javascript as my stack depending on the project.

RISC-V has a simple instruction encoding, but the 6502 has 151 instructions total.

I moved from 6502 assembly to PowerPC assembly. I found 6502 assembly easy to understand because of the limited number of registers, instructions and addressing modes. You didn't have to learn very many.

And as it turned out, I didn't have any problems adapting to the expanded PPC ISA. Being on the 6502 already taught me how to chop problems down into tiny bits and now the bits didn't have to be so tiny. I certainly wasn't trying to do 8-bit chained adds for bigger quantities anymore; it didn't make sense to when I had 32-bit registers and an FPU.

Same, learned as a kid. What was your motivation?

Mine was wanting to make games and hitting the performance wall in basic.

> modern RISC architectures such as ARM, MIPS or RISC-V. At some point, a serious assembly programmer should definitely learn some of them.

Yes.

> However, they are not ideal to start with: the “S” in RISC stands for “simple”, but the simplicity is more about internal implementation of the chips than the instruction set.

That is in fact a much better description of the 6502, which is not even a RISC but rather something almost prehistoric, where you figure out how much circuitry you could fit on a chip (or board) and then figured out what instruction set you could fit to that hardware.

Note that 6502 was the first machine code I learned as a 17 year old in 1980, after I got bored with BASIC after two days. I learned z80 on a ZX81 the year after and PDP-11 the same year. VAX in 1982, 6809 in 1983, and 68000 in 1984.

> Modern microprocessors are almost exclusively programmed with high-level languages and the direct usage of assembly instruction is not high on the list of priorities for CPU designers nowadays.

That's just absolutely not true.

They might be in some way "harder" than a CISC instruction set such as VAX but any of the above are far simpler to program than 6502, especially the base RISC-V RV32I instruction set.

> To illustrate this point, loading a 64-bit constant to a register on ARM64 can take 4 instructions with bit shifting.

Whereas you can't do it at all on a 6502! Loading a 64 bit constant into 8 zero page locations takes 16 instructions and 32 bytes of code on a 6502.

Let's not even talk about adding or comparing or multiplying two such values.

The GNU assembler for ARM64 doesn't help you out, but on RISC-V you can just type ...

    li x10,0xfedcba9876543210

... and the assembler will generate the multiple instructions for you.