jld’s gists

jld / gist:5871924

Created June 26, 2013 21:33

	function f(x) { let y = 0; while (x > 1) { if (x % 2 == 0) x /= 2; else x = x * 3 +1; ++y; } return y; }
	function g(a, b) { let t = 0; for(let i = a; i < b; ++i) { t+=f(i); } return t; }
	function h() { let n = 0; for(;;) { print(g(n10000, (n+1)10000)); ++n; } }
	h();

jld / gist:6302389

Created August 22, 2013 02:01

Note to self.

F/MOZ_Assert( 1109): Assertion failure: ((bool)(__builtin_expect(!!(!NS_FAILED_impl(rv)), 1))), at /home/jld/src/B2G/gecko/dom/ipc/TabChild.cpp:675

jld / gist:6373277

Created August 29, 2013 01:18

Go home, C++. You're drunk.

rustc: /usr/local/src/rust/src/llvm/include/llvm/Support/IntegersSubsetMapping.h:86: bool llvm::IntegersSubsetMapping<SuccessorClass, IntegersSubsetTy, IntTy>::isJoinable(llvm::IntegersSubsetMapping<SuccessorClass, IntegersSubsetTy, IntTy>::CaseItemIt&, llvm::IntegersSubsetMapping<SuccessorClass, IntegersSubsetTy, IntTy>::CaseItemIt&) [with SuccessorClass = llvm::MachineBasicBlock; IntegersSubsetTy = llvm::IntegersSubset; IntTy = llvm::IntItem; llvm::IntegersSubsetMapping<SuccessorClass, IntegersSubsetTy, IntTy>::CaseItemIt = std::_List_iterator<std::pair<llvm::IntegersSubsetMapping<llvm::MachineBasicBlock>::RangeEx, llvm::MachineBasicBlock*> >]: Assertion `!isIntersected(LItem, RItem) && "Intersected items with different successors!"' failed.

jld / gist:6395568

Created August 31, 2013 00:51

In which numbers are multiplied and divided.

	> (define (usable? n) (or (zero? n) (let ((i (modulo n 223))) (and (or (< i 26) (and (>= i 32) (< i (+ 32 26)))) (usable? (quotient n 223))))))
	> (time (let loop ((n 1)) (and (< n 100000000) (if (usable? (* n (expt 2 63))) n (loop (+ n 1))))))
	(time (let loop ((n 1)) (and (< n 100000000) (if (usable? (* n (expt 2 63))) n (loop (+ n 1))))))
	44377 ms real time
	44359 ms cpu time (44339 user, 20 system)
	58806 collections accounting for 2957 ms real time (2920 user, 0 system)
	17930827840 bytes allocated
	no minor faults
	no major faults
	23411452

jld / gist:6395576

Created August 31, 2013 00:53

In which OCaml's type system includes some rules not typically seen in theoretical presentations.

	# fun b -> if b then `DjEKseMUFXem else `AAAAAAAAAAAA;;
	Error: Variant tags `DjEKseMUFXem and `AAAAAAAAAAAA have the same hash value.
	Change one of them.

jld / exidx-count.py

Last active December 22, 2015 12:18

	import os, sys, struct, subprocess
	READELF = os.getenv("READELF") or "readelf"

	def main(argv):
	filename = argv[1]
	phdrs = subprocess.Popen([READELF, "-l", filename],
	stdout = subprocess.PIPE, stderr = sys.stderr)
	offset = None
	fsize = None
	for line in phdrs.stdout:

jld / bpfthing.S

Created October 10, 2013 18:53

	/*
	* The instruction encodings.
	*/
	/* instruction classes */
	#define BPF_CLASS(code) ((code) & 0x07)
	#define BPF_LD 0x00
	#define BPF_LDX 0x01
	#define BPF_ST 0x02
	#define BPF_STX 0x03
	#define BPF_ALU 0x04

jld / gist:7032403

Created October 17, 2013 21:22

	GITREPO=git://github.com/jld/b2g-manifest BRANCH=mac-keon ./config.sh keon
	./build.sh out/target/product/keon/boot.img

jld / gist:7128603

Created October 23, 2013 23:24

This backport probably won't work.

	# On branch seccomp-goldfish
	# You are currently cherry-picking.
	# (fix conflicts and run "git cherry-pick --continue")
	# (use "git cherry-pick --abort" to cancel the cherry-pick operation)
	#
	# Changes to be committed:
	#
	# new file: Documentation/prctl/no_new_privs.txt
	# new file: Documentation/prctl/seccomp_filter.txt
	# new file: arch/arm/include/asm/syscall.h

jld / gist:7270024

Last active December 27, 2015 04:49

hamachi kernel rebuild notes

	GITREPO=https://github.com/jld/b2g-manifest BRANCH=hamachi-kernel-maybe-broken ./config.sh hamachi
	rm -rf out
	./build.sh
	adb pull /dev/mtd/mtd0 orig-boot.img
	./flash.sh boot

	# At this point, if the device stays in the Alcatel boot screen,
	# it has an incompatible bootloader and this can't work.
	# Unbrick the phone thusly:
	fastboot flash boot orig-boot.img

Jed Davis jld