John Calsbeek Nexuapex

Nexuapex / kahan3.c

Created August 23, 2012 05:12

Kahan summation (3-way)

	float sum(float x0, float x1, float x2)
	{
	float accum = x0 + x1;
	float excess = (accum - x0) - x1;
	float addend = x2 - excess;
	return accum + addend;
	}

Nexuapex / dump.lua

Created June 17, 2012 02:50

Dumping a description of a Lua value

	local dump_table_threshold = 3
	local dump_indent = (" "):rep(4)

	local dumptable = {
	["nil"] = tostring,
	["number"] = tostring,
	["string"] = function(value) return "\"" .. value .. "\"" end,
	["boolean"] = tostring,
	["table"] = function(value, depth, markers)
	if markers[value] then

Nexuapex / reinterpret_f32_i32_sse.cc

Created February 18, 2012 05:10

Reinterpreting int ⇔ float with SSE

	#include <xmmintrin.h>

	inline int as_int_bitwise(float a)
	{
	return _mm_cvtsi128_si32(_mm_set_ss(a));
	}

	inline float as_float_bitwise(int a)
	{
	return _mm_cvtss_f32(_mm_cvtsi32_si128(a));

Nexuapex / icosahedron.cc

Created February 7, 2012 10:33

Icosahedron

	static GLfloat const minor = 0.5257311f;
	static GLfloat const major = 0.8506508f;

	float const icosahedron_position[12][3] = {
	{0.f, +minor, +major},
	{0.f, +minor, -major},
	{0.f, -minor, +major},
	{0.f, -minor, -major},
	{+major, 0.f, +minor},
	{+major, 0.f, -minor},

Nexuapex / 7segment.c

Created October 29, 2011 04:39

7-segment display in 50 lines of C99.