Vincent Isambart vincentisambart

GPU control flow

As I was trying to understand compute shaders, I had trouble grasping how the control flow was handled but I think I finally got it, so in case my understanding might help someone here it is. That should be mostly API agnostic.

For me it clicked when I tried to think about how I would write what a single wave/warp does with pseudo SIMD instructions and execution masks.

If you need some refresher on the confusing vocabulary, I'd recommend the Compute Shader 101 Glossary.

	# Warning: BUILD_DIRECTORY must be an absolute path for this script to work properly
	rm -rf $BUILD_DIRECTORY

	ARCHIVE_PATH=$BUILD_DIRECTORY/$TARGET.xcarchive
	IPA_PATH=$BUILD_DIRECTORY/$TARGET.ipa

	xcodebuild -workspace $WORKSPACE -scheme $SCHEME -derivedDataPath $BUILD_DIRECTORY -archivePath $ARCHIVE_PATH archive

	# As xcodebuild -exportArchive doesn't seem to work properly with WatchKit apps, I ended up making the IPA file by hand.
	# https://devforums.apple.com/message/1120211#1120211 has some information about doing that.

	" vim: fileencoding=utf8
	set termencoding=utf-8
	scriptencoding utf8
	set nocompatible
	set backspace=indent,eol,start
	set ru showcmd showmatch
	set incsearch
	set nowrap
	set iminsert=0 imsearch=0
	set expandtab softtabstop=2 shiftwidth=2

	#!/usr/bin/env ruby
	USR_LOCAL_INCLUDE = '/usr/local/include'
	def include_paths(language)
	include_paths = []
	in_list = false
	# LANG=C is forces cpp to output messages in English
	cpp_output = `LANG=C cpp -x #{language} -v < /dev/null 2>&1`
	cpp_output.each_line do \|line\|
	line.strip!
	if in_list

	Problem 1:
	Code:
	class A; def to_ary; [1, 2, 3, 4]; end; end
	a, b, *, c = A.new
	p [a, b, c]
	Arch: default
	Command: jruby --1.9
	Expectation: [1, 2, 4]
	Output: [#<A:0x2f2295>, nil, #<A:0x2f2295>]

	<?xml version="1.0" encoding="utf-8"?>
	<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
	<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="ja" lang="ja">
	<head>
	<meta http-equiv="content-type" content="text/html; charset=utf-8" />
	<title>test</title>
	<script src="http://maps.google.co.jp/maps/api/js?sensor=false" type="text/javascript"></script>
	<script type="text/javascript">
	function init() {
	var latLng = new google.maps.LatLng(35.660617498849, 139.72924947738647);

Vincent Isambart vincentisambart

GPU control flow

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