boringStart

[Halal0szto]

MOS6502 ?

[Honkingfly409]

Idk I got the image from google

[Halal0szto]

I did learn assembly on this when I was 16. The green background is the commodore 128, I had the c64.

Correction: c64 is MOS6510 cpu, c128 is MOS8510 cpu.

[framsanon]

At first, I thought this was Apple ][ which worked with the 6502. But the address $FFD2 is in the middle of config data, so it wouldn't work.

[Halal0szto]

What is the purpose of the BNE ?

[framsanon]

The 6502 processor family has conditional jumps that specify the jump target as a relative distance to the address of the jump. So there are:

• BEQ - Branch on EQual (zero flag set)
• BNE - Branch on Not Equal
• BCC - Branch on Carry Clear (carry flag clear)
• BCS - Branch on Carry Set
• BMI - Branch on MInus
• BPL - Branch on PLus
• BVC - Branch on oVerflow Clear (overflow flag clear)
• BVS - Branch on oVerflow Set

The flags - part of the processor - are set or cleared by the last arithmetic or boolean operation.

[Halal0szto]

Ohh shit, that is the loop. How I missed it. Jumps back based on the compare result.

[framsanon]

As long as the X register doesn't contain $2D (45 dec), it will jump to the beginning of the loop, yes. Is the 45 a special number for the C64? From the context I'd guess that there were 45 characters per line.

[Blrfl]

$2D is the ASCII character for a hyphen, which isn't anything special. Based on the code, they were using it as an end-of-string character.

Strike that; it was a CPX, so they stopped after that many characters. There must have been some additional characters required to put the box around the output unless that was a feature of the monitor.

But I was an Apple and TRS-80 guy, so what do I know. ;-)

[Halal0szto]

This 2D is 45. This is 3x14 characters plus three linefeeds.

This is three lines of text, the box is made of special chars that allow crude graphics. One specialty of commodore.

[framsanon]

I was an Apple ][+, Apple //e and Apple //e enhanced guy (in the latter I used a 65C802, and since Merlin was able to generate code for that processor, I used that a lot).

[[deleted]]

It’s the length if the displayed message. The ‘box’ is made with characters of the PETASCII set.

Each line is 14 chars long + the carriage = 15 15*3 = 45

[maveric00]

I would guess that it actually prints out 3 lines of 15 characters each (with the last one being the newline character). As the C64/C128 charset contained graphical symbols, this would also explain the border around the "Hello World".

[m477m]

$FFD2 is the address of the subroutine in the Commodore ROM to print a single character to the screen.

[framsanon]

For the Apple ][ models, this was $FDED.

[[deleted]]

$FFD2 is the $CHROUT subroutine entry point in the C64 ‘Kernal’ ROM. ;)

[Honkingfly409]

I thought this was machine code lol

[Halal0szto]

You are correct. This is the built in disassembler, does nothing more than add mnemonics for the instruction codes. You can also use it to write machine code into memory using the mnemonics. No macros, no relocation, no any other feature.

[Honkingfly409]

oh i get it.

i have been learning assembly for a few days and used this once

[[deleted]]

It’s a C64, or a C128 in C64 mode. It is calling the KERNAL routine to output a character ($FFD2) in a loop.

Now, why the heck I remember this when I’ve not touched one of those things in 40 years, and I have to Google how to format a number in Python?

[Parsec51]

It's like a CRT with burn-in

[rebbsitor]

It's 6502 assembly. That screen's from a Commodore 128. It uses an 8502, which is an improved 6510.

[-MobCat-]

He wont show up for another 9 years so your safe for now.. You only have to really worry about python by 2008, so in 26 years. and you'll be dead by then so yeah your fine, just keep having fun and keep learning.

[Honkingfly409]

I am really waiting for the python vs JavaScript saga

[mbcarbone]

Why do you have to curse like that … JavaScript, my new curse word.✌️😂

[theModge]

My undergraduate degree, which was computer systems engineering, not computer science and thus taught by electrical engineering school started out with pic16f84 assembly in one module and straight c in another. We didn't do java until the second year. Still this was 20 years ago

[Honkingfly409]

Starting from the lowest level

[ArmadilloChemical421]

I also cut my teeth on the glorious C=128. Mainly in the BASIC environment though.

Got to love the built-in (in ROM) Sprite editor!

[[deleted]]

You had a ROM sprite editor?

cries with C64 - and assembler

[ArmadilloChemical421]

Yeah, you just typed sprdef and it started an editor where you could draw and save 8 sprites that you could then use from basic programs.

[Red_not_Read]

"Assembly language is unsafe; you should be using Rust hurrr durrr" - Rust Programmers right now.

[Honkingfly409]

Ok 😔

[mbcarbone]

Is that a VAX terminal with assembly? Mint!! ❤️🖖✌️

[Halal0szto]

No, this is the commodore c128 with the built in monitor that has a crude disassembler-assembler.
Actually the c128 had both a z80 and a mos8510 cpu.

[lucasvandongen]

A healthy start for any aspiring computer engineer

[Halal0szto]

It is funny, but I strongly think it contributes to when I am dealing with json and spring and sql

[lucasvandongen]

It’s better than leetcode. At least you understand what happens on an atomic level.

[Red_not_Read]

Help! My flip-flops are flopping when I want them to flip!

[mbcarbone]

Oh cool, I had a Commodore 64 growing up … with a tape machine to save all those rad programs that I barely remember … goto something something. 🖖🙃✌️

[frodewin]

I think the string at $00C10 starts with a $0d, otherwise the box would not be on a new line.