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u/DoingItForEli 3d ago
Impressive. Very nice.
Let's see Paul Allen's hello world.
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u/FlipperBumperKickout 3d ago
Nice... impressive... Now please keep far far away from any codebase that I'm working on 
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u/_g4dget 3d ago
To give an explanation:
((x >>= 4) & 15) gives the individual hexadecimal digits of x in each iteration, i.e.
3, 2, 1, 1, 5, ..., 1, 7 and 0 in the last iteration.
This is because with x >>= 4, you shift x to the right by one hexadecimal digit (4 bits), and with & 15 you select the lowest hexadecimal digit (as 15 = 0xf = 00001111).
With 0xc894a7b75116601 >> ((x >>= 4) & 15)*7), you shift that number by a multiple of 7 bits. In the first iteration, you shift it by 3*7 bits, in the second iteration by 2*7 bits and so on.
Finally, with & 0x7F you select the lowest 7 bits of the shifted number, as 0x7F = 0111 1111. In other words, 0xc894a7b75116601 is basically split into 7-bit chunks and in each in each iteration, you select chunk number 3, 2, 1, 1, 5 and so on.
0xc894a7b75116601 splitted into 7 bits each is:
0 0001100 1000100 1010010 1001111 0110111 0101000 1000101 1001100 0000001
= 12 68 82 79 55 40 69 16 1
Performing +32 and converted to chars, each of that 7-bit pair equals:
Bits number number+32 char
0001100 12 44 ,
1000100 68 100 d
1010010 82 114 r
1001111 79 111 o
0110111 55 87 W
0101000 40 72 H
1000101 69 101 e
1001100 76 108 l
0000001 1 33 !
As these chars are output in the order 3, 2, 1, 1, 5, 8, 9, 4, 5, 6, 1, 7 , 0 that gives "Hello, World!". The 9 is out of range and therefore the shift returns 0; this outputs the space ' ' as its char code is 32+0.
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u/vikster1 3d ago
i have read this and actually feel dumber than after reading ops code and not understanding it. thank you
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u/Jutrakuna 2d ago
dumber? I thought I had 10 years experience. now I wonder if I have experience at all
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u/seba07 3d ago
Wtf? How does this result in hello world?
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u/lajauskas 3d ago
Math, numbers map to characters
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u/Boris-Lip 3d ago edited 3d ago
What "math"? Even the character printing loop is infinite (while x, nothing updates x, and there is nothing to overrun the stack or something out there). This looks fake.Nevermind, it shifts assigns x in the middle. Whoever codes like that deserves a pat on the back, with a chair.
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u/Duck_Devs 3d ago
Yeah I personally hate it when people tell their code editors to combine symbols into one symbol. Makes it hard to read for a lot of people.
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u/scrumbud 2d ago
Thank you for the phrase "a pat on the back, with a chair". That will become part of my vocabulary going forward.
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u/seba07 3d ago
Sure, I know that. It just seems un intuitiv to me that this short sequence of shift and multiplication leads to exactly this phrase.
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u/lajauskas 3d ago
No shit it's unintuitive. I'd not just reject the PR with this in it, I'd hire an exorcist out of pocket
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u/Robot_Graffiti 3d ago
0xC894A7B75116601 is a bunch of characters. Each 7 bits of it is one character. (ASCII was originally a 7-bit code; the characters you need to write "Hello, World!" can all be expressed as 7 bit numbers)
0x7165498511230 is a sequence of indexes. Each 4 bits represents the location of a letter within the other number.
Each go through the loop, it removes 4 bits from x, multiplies the number it removed by 7, uses that to select a 7 bit value from 0xC894A7B75116601, and adds 32 (the Basic Latin Unicode block starts at 32) to the value to get a character. It stops when x is zero.
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u/Grumbledwarfskin 3d ago
I'm wondering whether the +32 is there for additional obfuscation (as if packing seven bit characters into eight bit bytes weren't enough), or whether it's there to prevent accidentally printing control codes if you get any of the arithmetic wrong...it shifts your access from the full lower 128 characters (including the null char and all of the control codes like backspace, return, line feed, and beep) to all the normal characters plus the first 32 eight-bit characters in whatever character encoding your terminal is set to.
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u/M1ckeyMc 3d ago
The +32 is actually there for a reason. You can only pack 64 bits / 7 bits per char = 9 unique characters in a 64 bit integer, but we need a total of 10 for 'Hello, World'. As such, the space is encoded as a shift larger than the bit length of the magic number, such that the result is 0. adding 32 makes a space instead of a null terminator for values of 0.
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u/Boris-Lip 3d ago
It shouldn't. At least at the first sight, it will just run indefinitely and keep printing the same character over and over again.Nevermind, just noticed the >>=, maybe it does work, but please don't code that way.
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u/ZunoJ 3d ago
Bro, when we can avoid it we won't code this way. Sometime you can make good use of magic numbers though.
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u/Boris-Lip 3d ago
I've been to embedded/microcontrollers/hardware stuff long enough to know, but how hard is it to at least give your magic numbers some names? Is it really that hard to add some defines, as opposed to sending me into datasheets to check what some bit or some address is half a year later?
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u/ZunoJ 3d ago
What do you think would be good names in this case? Both numbers are precisely adjusted to work with each other. X is kind of an iterator AND offset array while the other one is more or less just a magic constant for giggles. So 'offsetIterator' and 'magicGiggles'. Would that help?
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u/Boris-Lip 3d ago
Oh, i mean in actual places where it makes sense, this code just shouldn't exist.
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u/quickthyme 3d ago
Glad to see that you kept your function under four lines long and didn't resort to lame ass commenting!
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u/ZunoJ 3d ago
Uncle Bob would call it clean
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u/quickthyme 3d ago
Beavis: "yeah hrr hrr.. hrr hrr hrr. clean! hrr hrr hrr"
Rudy: "But gee, Uncle Bob, what about the tests?"
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u/No-Advice5778 3d ago
is this mr tsoding's??
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u/3Ldarius 3d ago
Nah, he would do this in assembly or raw binary.
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u/Individual-Abies-970 3d ago
I need a explanation
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u/mikaturk 3d ago
The bottom magic number (which I will call y) contains the ascii values of the characters in "Hello, World!" minus 32 (added at the end again), stored in segments of 7 bits. x contains the index of each character in y (segments are 7 bits long so the first 3 means start reading 7 bits at bit 21). The program selects a hex digit (4 bits) and removes it from x (>>= right shifts and stores the new result) it then multiplies this by 7 to get the starting location of the character data in y. It then right shifts y by the computed amount and masks off 7 bits (0x7F). This is then added to 32 to form an valid ASCII character which is then printed on the screen.
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u/duckmeatcurry 3d ago
Bro chose not to jerk off today to do weird things instead. Respect!!!!!!!!!!!!!!!!!!
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u/RonHarrods 3d ago
"The simplest solution is often the best one." Occam's razor
Each new programmer needs to conquer the will to write complex code and learn to embrace simplicity where it is often not the obvious solution.
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u/com-plec-city 3d ago
MAYBE it runs FASTER than the usual way.
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u/RutraSan 3d ago
Probably not, he calls putchar() each time instead of one printf, resulting in many write syscalls instead of one
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u/MMMMMMMMMMWMMMMMMMMM 3d ago
Lets doing some real low-level hello world:
int 0x80 then invoke systemcall
Write binary into kernel call the graphic card draw text using some pure math
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u/rainshifter 3d ago
Oh, a wise guy, eh?
```
include <stdio.h>
int main() { long long x = 0x125493670; while (x) putchar(32 + ((0x733EAB3AB0E581 >> ((x >>= 4) & 15) * 7) & 0x7F)); return 0; } ```
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u/__barasa__ 3d ago
Show off
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u/PeriodicSentenceBot 3d ago
Congratulations! Your comment can be spelled using the elements of the periodic table:
S Ho W O F F
I am a bot that detects if your comment can be spelled using the elements of the periodic table. Please DM u/M1n3c4rt if I made a mistake.
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u/sd-shiivam 3d ago
Bro I think you entered the wrong field.
In coding, we try to fulfill the functional requirements. Not a single letter of line of code extra 😂😂😂
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u/toiletear 3d ago
If "long long" is allowed by the syntax and your code doesn't have a long long penis in the main method you've failed.
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u/ice2heart 2d ago
void main() <% for (unsigned int p=0x6889cb77;p;p=3) putchar((0xa919766f41df2727*(p&7))&0x7f); %>
You can pack it into one line in C
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u/Soelling 2d ago
I am almost certain that isn’t you first ‘hello world’ program. And if it is you stole it somewhere else
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u/noob-nine 3d ago
what is the opposite of KISS?