camel-cdr’s gists

camel-cdr / random.h

Last active March 5, 2021 21:48

How to generate unbiased uniform random floating-point numbers including all representable values. An excerpt from the random number library I'm currently developing.

	/*
	* 5.2 Uniform real distribution -----------------------------------------------
	*
	* Generating uniform random floating-point numbers might seem easy at first
	* glance, just cast the output of a PRNG to the desired float type and divide
	* by the biggest possible output of the PRNG to obtain a random float between
	* 0 and 1 that can now be scaled up.
	* Though as before this straightforward approach is biased.
	*
	* For the next part, I assume you are already acquainted with the IEEE 754

camel-cdr / list.c

Created March 5, 2021 21:51

Remember kids, C's got namespaces.

	struct list { struct list *list; };

	struct list *
	list(struct list *list)
	{
	list:
	if (list->list && (list = list->list))
	goto list;
	return list;
	}

camel-cdr / torus.c

Last active December 19, 2022 15:30

obfuscated raymarcher

	i,j,k,L;
	#include <time.h>
	float X,Y,Z,l,t,x,y,z,
	A,S,C;r(X,Y)floatX,Y;{A
	=X,S=sin(l),C=cos(l);X=A*C
	-YS,Y=AS+Y C;}main()
	{charp,s[L=( W+1)H];
	printf("\x1b" "[2J");r
	:p=s;for(i=0; i<H;++i,
	*p++=10)for(j =0;j<W;

camel-cdr / main.c

Last active June 18, 2021 12:33

ranged designated initializers in c99

	#include <stdio.h>

	#define E2(...) E1(E1(E1(E1(E1(E1(E1(E1(E1(E1(__VA_ARGS__))))))))))
	#define E1(...) __VA_ARGS__
	#define EMPTY()
	#define DEFER1(m) m EMPTY()

	#define APPLY3(F,a,x,y,v) F(a,0,x,y,v), F(a,1,x,y,v), F(a,2,x,y,v), \
	F(a,3,x,y,v), F(a,4,x,y,v), F(a,5,x,y,v), \
	F(a,6,x,y,v), F(a,7,x,y,v), F(a,8,x,y,v), \

camel-cdr / xor.c

Created June 18, 2021 12:32

xor encryption using the preprocessor (Idea from https://www.reddit.com/r/C_Programming/comments/o2lgt3/constexpr_in_c/)

	#include <stdio.h>

	#define E2(...) E1(E1(E1(E1(E1(E1(E1(E1(E1(E1(__VA_ARGS__))))))))))
	#define E1(...) __VA_ARGS__
	#define EMPTY()
	#define DEFER1(m) m EMPTY()

	#define APPLY3(F,a,m,k) F(a,0,m,k), F(a,1,m,k), F(a,2,m,k), \
	F(a,3,m,k), F(a,4,m,k), F(a,5,m,k), \
	F(a,6,m,k), F(a,7,m,k), F(a,8,m,k), \

camel-cdr / gen.c

Last active February 19, 2022 12:09

C code that is syntactically correct only on Fridays

	#include <stdio.h>
	#include <time.h>

	static const char mon_name[12][3] = {
	"Jan", "Feb", "Mar", "Apr", "May", "Jun",
	"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
	};

	int
	main(void)

camel-cdr / ppmp-bootstrap.c

Last active March 6, 2022 22:55

C preprocessor continuation machine with some helper macros

	#define XXX_CM_UP_0(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_1 (XXX_CM_PASS_DN_0 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_ARGS__)))
	#define XXX_CM_UP_1(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_2 (XXX_CM_PASS_DN_1 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_ARGS__)))
	#define XXX_CM_UP_2(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_3 (XXX_CM_PASS_DN_2 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_ARGS__)))
	#define XXX_CM_UP_3(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_4 (XXX_CM_PASS_DN_3 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_ARGS__)))
	#define XXX_CM_UP_4(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_5 (XXX_CM_PASS_DN_4 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_ARGS__)))
	#define XXX_CM_UP_5(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_6 (XXX_CM_PASS_DN_5 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_ARGS__)))
	#define XXX_CM_UP_6(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_7 (XXX_CM_PASS_DN_6 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_ARGS__)))
	#define XXX_CM_UP_7(P,a,b,c,d,e,f,...) XXX_CM_PASS_UP_8 (XXX_CM_PASS_DN_7 (XXX__##f(,P##a,P##b,P##c,P##d,P##e,P##__VA_AR

camel-cdr / detect-macchanger.c

Last active January 8, 2023 19:27

detects if a MAC address was generated using macchanger --random

	#include <stdint.h>
	#include <stdlib.h>
	#include <stdio.h>
	#include <limits.h>
	#ifdef _OPENMP
	#include <omp.h>
	#endif

	/*
	* macchanger --random uses the following code to generate random MAC addresses:

camel-cdr / rvv-rollback.S

Last active July 28, 2023 17:04

Assembly macros to aid in writing rvv 1.0 and rvv 0.7 compatible code

	# rvv-rollback.S -- A minimal benchmarking library
	# Olaf Bernstein <[email protected]>
	# Distributed under the MIT license, see license at the end of the file.
	# New versions available at https://gist.github.com/camel-cdr/cfd9ba2b8754b521edf4892fe19c7031
	# Conversions taken from https://github.com/RISCVtestbed/rvv-rollback

	.macro vle32.v a:vararg
	vlw.v \a
	.endm
	.macro vle16.v a:vararg

camel-cdr / rvv-shishua.S

Last active February 21, 2025 02:21

rvv shishua

	.global shishua_rvv # void shishua_rvv (uint64_t state[4], void *dest, size_t n)
	shishua_rvv:
	# load state (can easily be expanded to state[8] or state[16])
	vsetvli t6, x0, e64, m2, ta, ma
	ld a4, 0(a0)
	vmv.v.x v0, a4
	ld a4, 8(a0)
	vmv.v.x v4, a4
	ld a4, 16(a0)
	vmv.v.x v8, a4

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