diff --git a/README.md b/README.adoc
similarity index 64%
rename from README.md
rename to README.adoc
index 5540e41..6c282db 100644
--- a/README.md
+++ b/README.adoc
@@ -1,4 +1,4 @@
-# OpenCL-Registry
+= OpenCL-Registry
 
 The OpenCL-Registry repository contains the OpenCL API and Extension
 Registry, including specifications, reference pages and reference cards, and
@@ -11,45 +11,33 @@
 but it is still available at
 https://cvs.khronos.org/svn/repos/registry/trunk/public/cl/ .
 
-Interesting files in this repository include:
+== Reserving OpenCL Enumerant Ranges
 
-* index.php - toplevel index page for the web view. This relies on PHP
-  include files found elsewhere on www.khronos.org and so is not very useful
-  in isolation.
-* api/cl.xml - enumerant and extension number registry. Documents the
-  assigned OpenCL enumerant ranges, and the names and index numbers assigned
-  to OpenCL extension specifications.
-* extensions/ - OpenCL extension specifications, grouped into
-  vendor-specific subdirectories.
-* sdk/ - OpenCL reference pages and reference cards. There are separate sets
-  for each API version.
-* specs/ - OpenCL specification documents.
-
-
-## Reserving OpenCL Enumerant Ranges
-
-OpenCL enumerants are documented in api/cl.xml . New ranges can be allocated
+OpenCL enumerants are documented in xml/cl.xml . New ranges can be allocated
 by proposing a pull request to master modifying this file, following the
 existing examples. Allocate ranges starting at the lowest free values
 available (search for "Reserved for vendor extensions"). Ranges are not
 officially allocated until your pull request is *accepted* into master. At
 that point you can use values from your assigned range for API extensions.
 
-
-## Adding Extension Specifications
+== Adding Extension Specifications
 
 Extension specification documents can be added by proposing a pull request
 to master, adding the specification .txt file under
 extensions/<vendor>/filename.txt . You must also:
 
-* Allocate an extension number in api/cl.xml (follow the existing
-  <extension> examples, search for "Next free extension number", and use the
-  lowest available extension number).
-* Include that extension number in the extension specification document.
-* Add a link from the extensions section of index.php to the extension
-  document, using the specified extension number, so it shows up in the web
-  view (this could in principle be generated automatically from cl.xml, but
-  isn't at present).
+* Modify extensions/registry.py to include the extension, using the next
+  free extension number. Execute the python script nextfree.py in the
+  extensions/ directory to find the next free number. The extension 'flags'
+  must be marked as 'public', similar to other entries in registry.py, for
+  the extension to be linked from the registry index page.
+* Include that extension number in the extension specification document
+* In the extensions/ directory, 'make' to regenerate the HTML index file
+  'clext.php' from registry.py. If this doesn't succeed due to not having
+  the right Python version or something like that, we'll take care of it
+  when merging to master.
+* We are no longer registering extension numbers in xml/cl.xml, for
+  consistency with the combined GL registry scripts.
 
 Sometimes extension text files contain inappropriate UTF-8 characters. They
 should be restricted to the ASCII subset of UTF-8 at present. They can be
@@ -61,3 +49,25 @@
 
 We will be transitioning to an asciidoc-based extension specification format
 at some point.
+
+== Repository Contents
+
+Interesting files in this repository include:
+
+* index.php - toplevel index page for the web view. This relies on PHP
+  include files found elsewhere on www.khronos.org and so is not very useful
+  in isolation.
+* xml/cl.xml - enumerant and extension number registry. Documents the
+  assigned OpenCL enumerant ranges, and the names and index numbers assigned
+  to OpenCL extension specifications.
+* extensions/ - OpenCL extension specifications, grouped into
+  vendor-specific subdirectories.
+** extensions/registry.py - extension registry.
+** extensions/makeindex.py - create HTML extension indices from registry.py.
+** extensions/nextfree.py - determine the next free extension number in
+   registry.py.
+* sdk/ - OpenCL reference pages and reference cards. There are separate sets
+  for each API version.
+* specs/ - OpenCL specification documents.
+
+
diff --git a/extensions/Makefile b/extensions/Makefile
new file mode 100644
index 0000000..aee1e80
--- /dev/null
+++ b/extensions/Makefile
@@ -0,0 +1,26 @@
+# Copyright (c) 2017 The Khronos Group Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Generate the PHP index file includes for OpenGL ARB, OpenGL ES, and
+# OpenGL EXT/Vendor extensions.
+
+# python3 is required. Sorry, python2 dudes.
+
+PYTHON = python3
+SCRIPTS = registry.py makeindex.py
+
+all: clext.php
+
+clext.php: $(SCRIPTS)
+	$(PYTHON) makeindex.py number >$@
diff --git a/extensions/clext.php b/extensions/clext.php
new file mode 100644
index 0000000..955d7d2
--- /dev/null
+++ b/extensions/clext.php
@@ -0,0 +1,102 @@
+<ol>
+<li value=1><a href="extensions/khr/cl_khr_gl_sharing.txt">cl_khr_gl_sharing</a>
+</li>
+<li value=2><a href="extensions/nv/cl_nv_d3d9_sharing.txt">cl_nv_d3d9_sharing</a>
+</li>
+<li value=3><a href="extensions/nv/cl_nv_d3d10_sharing.txt">cl_nv_d3d10_sharing</a>
+</li>
+<li value=4><a href="extensions/nv/cl_nv_d3d11_sharing.txt">cl_nv_d3d11_sharing</a>
+</li>
+<li value=5><a href="extensions/khr/cl_khr_icd.txt">cl_khr_icd</a>
+</li>
+<li value=6><a href="extensions/khr/cl_khr_d3d10_sharing.txt">cl_khr_d3d10_sharing</a>
+</li>
+<li value=7><a href="extensions/amd/cl_amd_device_attribute_query.txt">cl_amd_device_attribute_query</a>
+</li>
+<li value=8><a href="extensions/amd/cl_amd_fp64.txt">cl_amd_fp64</a>
+</li>
+<li value=9><a href="extensions/amd/cl_amd_media_ops.txt">cl_amd_media_ops</a>
+</li>
+<li value=10><a href="extensions/ext/cl_ext_migrate_memobject.txt">cl_ext_migrate_memobject</a>
+</li>
+<li value=11><a href="extensions/ext/cl_ext_device_fission.txt">cl_ext_device_fission</a>
+</li>
+<li value=12><a href="extensions/ext/cl_ext_atomic_counters_32.txt">cl_ext_atomic_counters_32</a>
+</li>
+<li value=13><a href="extensions/ext/cl_ext_atomic_counters_64.txt">cl_ext_atomic_counters_64</a>
+</li>
+<li value=14><a href="extensions/intel/cl_intel_dx9_media_sharing.txt">cl_intel_dx9_media_sharing</a>
+</li>
+<li value=15><a href="extensions/amd/cl_amd_media_ops2.txt">cl_amd_media_ops2</a>
+</li>
+<li value=16><a href="extensions/intel/cl_intel_thread_local_exec.txt">cl_intel_thread_local_exec</a>
+</li>
+<li value=17><a href="extensions/nv/cl_nv_compiler_options.txt">cl_nv_compiler_options</a>
+</li>
+<li value=18><a href="extensions/nv/cl_nv_device_attribute_query.txt">cl_nv_device_attribute_query</a>
+</li>
+<li value=19><a href="extensions/nv/cl_nv_pragma_unroll.txt">cl_nv_pragma_unroll</a>
+</li>
+<li value=20><a href="extensions/intel/cl_intel_device_partition_by_names.txt">cl_intel_device_partition_by_names</a>
+</li>
+<li value=21><a href="extensions/qcom/cl_qcom_ext_host_ptr.txt">cl_qcom_ext_host_ptr</a>
+</li>
+<li value=22><a href="extensions/qcom/cl_qcom_ion_host_ptr.txt">cl_qcom_ion_host_ptr</a>
+</li>
+<li value=23><a href="extensions/intel/cl_intel_motion_estimation.txt">cl_intel_motion_estimation</a>
+</li>
+<li value=24><a href="extensions/intel/cl_intel_accelerator.txt">cl_intel_accelerator</a>
+</li>
+<li value=25><a href="extensions/amd/cl_amd_bus_addressable_memory.txt">cl_amd_bus_addressable_memory</a>
+</li>
+<li value=26><a href="extensions/arm/cl_arm_get_core_id.txt">cl_arm_core_id</a>
+</li>
+<li value=27><a href="extensions/arm/cl_arm_printf.txt">cl_arm_printf</a>
+</li>
+<li value=28><a href="extensions/altera/cl_altera_live_object_tracking.txt">cl_altera_live_object_tracking</a>
+</li>
+<li value=29><a href="extensions/altera/cl_altera_device_temperature.txt">cl_altera_device_temperature</a>
+</li>
+<li value=30><a href="extensions/altera/cl_altera_compiler_mode.txt">cl_altera_compiler_mode</a>
+</li>
+<li value=31><a href="extensions/intel/cl_intel_d3d11_nv12_media_sharing.txt">cl_intel_d3d11_nv12_media_sharing</a>
+</li>
+<li value=32><a href="extensions/qcom/cl_qcom_android_native_buffer_host_ptr.txt">cl_qcom_android_native_buffer_host_ptr</a>
+</li>
+<li value=33><a href="extensions/intel/cl_intel_advanced_motion_estimation.txt">cl_intel_advanced_motion_estimation</a>
+</li>
+<li value=34><a href="extensions/intel/cl_intel_simultaneous_sharing.txt">cl_intel_simultaneous_sharing</a>
+</li>
+<li value=35><a href="extensions/intel/cl_intel_subgroups.txt">cl_intel_subgroups</a>
+</li>
+<li value=36><a href="extensions/intel/cl_intel_va_api_media_sharing.txt">cl_intel_va_api_media_sharing</a>
+</li>
+<li value=37><a href="extensions/intel/cl_intel_egl_image_yuv.txt">cl_intel_egl_image_yuv</a>
+</li>
+<li value=38><a href="extensions/arm/cl_arm_import_memory.txt">cl_arm_import_memory</a>
+</li>
+<li value=39><a href="extensions/arm/cl_arm_non_uniform_work_group_size.txt">cl_arm_non_uniform_work_group_size</a>
+</li>
+<li value=40><a href="extensions/arm/cl_arm_shared_virtual_memory.txt">cl_arm_shared_virtual_memory</a>
+</li>
+<li value=41><a href="extensions/arm/cl_arm_thread_limit_hint.txt">cl_arm_thread_limit_hint</a>
+</li>
+<li value=42><a href="extensions/intel/cl_intel_packed_yuv.txt">cl_intel_packed_yuv</a>
+</li>
+<li value=43><a href="extensions/intel/cl_intel_required_subgroup_size.txt">cl_intel_required_subgroup_size</a>
+</li>
+<li value=44><a href="extensions/img/cl_img_cached_allocations.txt">cl_img_cached_allocations</a>
+</li>
+<li value=45><a href="extensions/img/cl_img_use_gralloc_ptr.txt">cl_img_use_gralloc_ptr</a>
+</li>
+<li value=46><a href="extensions/img/cl_img_yuv_image.txt">cl_img_yuv_image</a>
+</li>
+<li value=47><a href="extensions/intel/cl_intel_driver_diagnostics.txt">cl_intel_driver_diagnostics</a>
+</li>
+<li value=48><a href="extensions/intel/cl_intel_subgroups_short.txt">cl_intel_subgroups_short</a>
+</li>
+<li value=49><a href="extensions/intel/cl_intel_planar_yuv.txt">cl_intel_planar_yuv</a>
+</li>
+<li value=50><a href="extensions/intel/cl_intel_device_side_avc_motion_estimation.txt">cl_intel_device_side_avc_motion_estimation</a>
+</li>
+</ol>
diff --git a/extensions/makeindex.py b/extensions/makeindex.py
new file mode 100755
index 0000000..d0b7309
--- /dev/null
+++ b/extensions/makeindex.py
@@ -0,0 +1,88 @@
+#!/usr/bin/python3
+#
+# Copyright (c) 2017 The Khronos Group Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# makeindex.py - create HTML indices for the OpenGL extension registry
+#
+# Use: makeindex.py key
+# where 'key' is 'arbnumber', 'number', or 'esnumber' for ARB OpenGL,
+# Vendor OpenGL, and OpenGL ES extensions, respectively.
+#
+# Only extensions marked 'public' will be included in the index.
+
+import copy, os, re, string, sys
+
+# Keys in glregistry:
+#   arbnumber   OpenGL ARB extension # (if present)
+#   number      OpenGL vendor/EXT extension # (if present)
+#   esnumber    OpenGL ES extension # (if present)
+#   flags       Set containing one or more of 'public' 'private' 'obsolete' 'incomplete'
+#   url         Relative URL to extension spec
+#   esurl       Relative URL to ES-specific extension spec (if present)
+#   alias       Set of additional extension strings defined in the same document
+#   comments    Arbitrary string with metainformation about the extension
+#   supporters  Set of strings with supporting vendor names (both obsolete
+#               and incomplete - useless save for historical purposes)
+
+def makeLink(name, link):
+    return '<a href="' + url + '">' + name + '</a>'
+
+# See if the specified key of the extension has the specified flag
+def hasFlag(extension, key, flag):
+    return (key in extension and flag in extension[key])
+
+if __name__ == '__main__':
+    if (len(sys.argv) > 1):
+        key = sys.argv[1]
+    else:
+        key = 'number'
+
+    isGLES = (key == 'esnumber')
+
+    # print('makeindex: key =', key)
+
+    # Load the registry
+    file = 'registry.py'
+    exec(open(file).read())
+
+    # Select extensions with the matching key
+    dict = {k:v for k,v in registry.items() if key in v.keys()}
+
+    # print('Filtered', len(dict), 'extensions')
+
+    # Sort matching extensions by the key value
+    sortext = sorted(dict.items(), key = lambda kv : kv[1].get(key))
+
+    # Generate the HTML ordered list of extensions (selecting only public ones)
+    print('<ol>')
+    for (name,ext) in sortext:
+        index = ext.get(key)
+
+        if hasFlag(ext, 'flags', 'public'):
+            # Only select the alternate ES path if we're generating the ES index
+            if (isGLES and 'esurl' in ext):
+                url = ext['esurl']
+            else:
+                url = ext['url']
+
+            # Create the main indexed link
+            print('<li value=', index, '>', makeLink(name, url), sep='')
+
+            if ('alias' in ext):
+                for alias in ext['alias']:
+                    print('\n    <br> ', makeLink(alias, url), sep='')
+
+            print('</li>')
+    print('</ol>')
diff --git a/extensions/nextfree.py b/extensions/nextfree.py
new file mode 100755
index 0000000..3085041
--- /dev/null
+++ b/extensions/nextfree.py
@@ -0,0 +1,50 @@
+#!/usr/bin/env python
+#
+# Copyright (c) 2017 The Khronos Group Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# nextfree.py - determine the next unused extension numbers.
+# Use this when registering a new ARB, vendor, and/or OpenGL ES extension.
+#
+# Use: nextfree.py
+
+import copy, os, re, string, sys
+
+def write(*args, **kwargs):
+    file = kwargs.pop('file', sys.stdout)
+    end = kwargs.pop('end', '\n')
+    file.write(' '.join([str(arg) for arg in args]))
+    file.write(end)
+
+# Load the registry
+file = 'registry.py'
+exec(open(file).read())
+
+# Track the next free extension number
+keys = { 'number' }
+max = {}
+for k in keys:
+    max[k] = 0
+
+# Loop over all extensions updating the max value
+for name,v in registry.items():
+    for k in keys:
+        if k in v.keys():
+            n = v[k]
+            if (n > max[k]):
+                max[k] = n
+
+# Report next free values
+for k in keys:
+    write('Next free', k, '=', max[k] + 1)
diff --git a/extensions/printreg.py b/extensions/printreg.py
new file mode 100755
index 0000000..405a9ea
--- /dev/null
+++ b/extensions/printreg.py
@@ -0,0 +1,74 @@
+#
+# Copyright (c) 2017 The Khronos Group Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# printreg(reg, varname)
+# Prints a registry Python data structure (see registry.py) in a consistent
+# fashion.
+
+def tab():
+    return '        '
+
+def quote(str):
+    return '\'' + str + '\''
+
+def printKey(key, value):
+    print(tab() + quote(key), ':', value + ',')
+
+def printNum(ext, key):
+    if (key in ext.keys()):
+        printKey(key, str(ext[key]))
+
+def printSet(ext, key):
+    if (key in ext.keys()):
+        value = ( '{ ' +
+                  ', '.join([quote(str(tag)) for tag in sorted(ext[key])]) +
+                  ' }' )
+        printKey(key, value)
+
+def printStr(ext, key):
+    if (key in ext.keys()):
+        printKey(key, quote(str(ext[key])))
+
+def striplibs(s):
+    return ( s.replace('GL_','').
+               replace('GLU_','').
+               replace('GLX_','').
+               replace('WGL_','') )
+
+def printreg(reg, varname):
+    print(varname, '= {')
+
+    # print('keys in registry =', len(reg.keys()))
+
+    print('# OpenGL extension number and name registry')
+    print('')
+
+    for key in sorted(reg.keys(), key = striplibs):
+        ext = reg[key]
+
+        print('    ' + quote(key), ': {')
+        printNum(ext, 'arbnumber')
+        printNum(ext, 'number')
+        printNum(ext, 'esnumber')
+        printSet(ext, 'flags')
+        printSet(ext, 'supporters')
+        printStr(ext, 'url')
+        printStr(ext, 'esurl')
+        printSet(ext, 'alias')
+        printStr(ext, 'comments')
+        print('    },')
+
+    print('}')
+
diff --git a/extensions/registry.py b/extensions/registry.py
new file mode 100644
index 0000000..70453a8
--- /dev/null
+++ b/extensions/registry.py
@@ -0,0 +1,254 @@
+registry = {
+# OpenGL extension number and name registry
+
+    'cl_altera_compiler_mode' : {
+        'number' : 30,
+        'flags' : { 'public' },
+        'url' : 'extensions/altera/cl_altera_compiler_mode.txt',
+    },
+    'cl_altera_device_temperature' : {
+        'number' : 29,
+        'flags' : { 'public' },
+        'url' : 'extensions/altera/cl_altera_device_temperature.txt',
+    },
+    'cl_altera_live_object_tracking' : {
+        'number' : 28,
+        'flags' : { 'public' },
+        'url' : 'extensions/altera/cl_altera_live_object_tracking.txt',
+    },
+    'cl_amd_bus_addressable_memory' : {
+        'number' : 25,
+        'flags' : { 'public' },
+        'url' : 'extensions/amd/cl_amd_bus_addressable_memory.txt',
+    },
+    'cl_amd_device_attribute_query' : {
+        'number' : 7,
+        'flags' : { 'public' },
+        'url' : 'extensions/amd/cl_amd_device_attribute_query.txt',
+    },
+    'cl_amd_fp64' : {
+        'number' : 8,
+        'flags' : { 'public' },
+        'url' : 'extensions/amd/cl_amd_fp64.txt',
+    },
+    'cl_amd_media_ops' : {
+        'number' : 9,
+        'flags' : { 'public' },
+        'url' : 'extensions/amd/cl_amd_media_ops.txt',
+    },
+    'cl_amd_media_ops2' : {
+        'number' : 15,
+        'flags' : { 'public' },
+        'url' : 'extensions/amd/cl_amd_media_ops2.txt',
+    },
+    'cl_arm_core_id' : {
+        'number' : 26,
+        'flags' : { 'public' },
+        'url' : 'extensions/arm/cl_arm_get_core_id.txt',
+    },
+    'cl_arm_import_memory' : {
+        'number' : 38,
+        'flags' : { 'public' },
+        'url' : 'extensions/arm/cl_arm_import_memory.txt',
+    },
+    'cl_arm_non_uniform_work_group_size' : {
+        'number' : 39,
+        'flags' : { 'public' },
+        'url' : 'extensions/arm/cl_arm_non_uniform_work_group_size.txt',
+    },
+    'cl_arm_printf' : {
+        'number' : 27,
+        'flags' : { 'public' },
+        'url' : 'extensions/arm/cl_arm_printf.txt',
+    },
+    'cl_arm_shared_virtual_memory' : {
+        'number' : 40,
+        'flags' : { 'public' },
+        'url' : 'extensions/arm/cl_arm_shared_virtual_memory.txt',
+    },
+    'cl_arm_thread_limit_hint' : {
+        'number' : 41,
+        'flags' : { 'public' },
+        'url' : 'extensions/arm/cl_arm_thread_limit_hint.txt',
+    },
+    'cl_ext_atomic_counters_32' : {
+        'number' : 12,
+        'flags' : { 'public' },
+        'url' : 'extensions/ext/cl_ext_atomic_counters_32.txt',
+    },
+    'cl_ext_atomic_counters_64' : {
+        'number' : 13,
+        'flags' : { 'public' },
+        'url' : 'extensions/ext/cl_ext_atomic_counters_64.txt',
+    },
+    'cl_ext_device_fission' : {
+        'number' : 11,
+        'flags' : { 'public' },
+        'url' : 'extensions/ext/cl_ext_device_fission.txt',
+    },
+    'cl_ext_migrate_memobject' : {
+        'number' : 10,
+        'flags' : { 'public' },
+        'url' : 'extensions/ext/cl_ext_migrate_memobject.txt',
+    },
+    'cl_img_cached_allocations' : {
+        'number' : 44,
+        'flags' : { 'public' },
+        'url' : 'extensions/img/cl_img_cached_allocations.txt',
+    },
+    'cl_img_use_gralloc_ptr' : {
+        'number' : 45,
+        'flags' : { 'public' },
+        'url' : 'extensions/img/cl_img_use_gralloc_ptr.txt',
+    },
+    'cl_img_yuv_image' : {
+        'number' : 46,
+        'flags' : { 'public' },
+        'url' : 'extensions/img/cl_img_yuv_image.txt',
+    },
+    'cl_intel_accelerator' : {
+        'number' : 24,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_accelerator.txt',
+    },
+    'cl_intel_advanced_motion_estimation' : {
+        'number' : 33,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_advanced_motion_estimation.txt',
+    },
+    'cl_intel_d3d11_nv12_media_sharing' : {
+        'number' : 31,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_d3d11_nv12_media_sharing.txt',
+    },
+    'cl_intel_device_partition_by_names' : {
+        'number' : 20,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_device_partition_by_names.txt',
+    },
+    'cl_intel_device_side_avc_motion_estimation' : {
+        'number' : 50,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_device_side_avc_motion_estimation.txt',
+    },
+    'cl_intel_driver_diagnostics' : {
+        'number' : 47,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_driver_diagnostics.txt',
+    },
+    'cl_intel_dx9_media_sharing' : {
+        'number' : 14,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_dx9_media_sharing.txt',
+    },
+    'cl_intel_egl_image_yuv' : {
+        'number' : 37,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_egl_image_yuv.txt',
+    },
+    'cl_intel_motion_estimation' : {
+        'number' : 23,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_motion_estimation.txt',
+    },
+    'cl_intel_packed_yuv' : {
+        'number' : 42,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_packed_yuv.txt',
+    },
+    'cl_intel_planar_yuv' : {
+        'number' : 49,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_planar_yuv.txt',
+    },
+    'cl_intel_required_subgroup_size' : {
+        'number' : 43,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_required_subgroup_size.txt',
+    },
+    'cl_intel_simultaneous_sharing' : {
+        'number' : 34,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_simultaneous_sharing.txt',
+    },
+    'cl_intel_subgroups' : {
+        'number' : 35,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_subgroups.txt',
+    },
+    'cl_intel_subgroups_short' : {
+        'number' : 48,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_subgroups_short.txt',
+    },
+    'cl_intel_thread_local_exec' : {
+        'number' : 16,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_thread_local_exec.txt',
+    },
+    'cl_intel_va_api_media_sharing' : {
+        'number' : 36,
+        'flags' : { 'public' },
+        'url' : 'extensions/intel/cl_intel_va_api_media_sharing.txt',
+    },
+    'cl_khr_d3d10_sharing' : {
+        'number' : 6,
+        'flags' : { 'public' },
+        'url' : 'extensions/khr/cl_khr_d3d10_sharing.txt',
+    },
+    'cl_khr_gl_sharing' : {
+        'number' : 1,
+        'flags' : { 'public' },
+        'url' : 'extensions/khr/cl_khr_gl_sharing.txt',
+    },
+    'cl_khr_icd' : {
+        'number' : 5,
+        'flags' : { 'public' },
+        'url' : 'extensions/khr/cl_khr_icd.txt',
+    },
+    'cl_nv_compiler_options' : {
+        'number' : 17,
+        'flags' : { 'public' },
+        'url' : 'extensions/nv/cl_nv_compiler_options.txt',
+    },
+    'cl_nv_d3d10_sharing' : {
+        'number' : 3,
+        'flags' : { 'public' },
+        'url' : 'extensions/nv/cl_nv_d3d10_sharing.txt',
+    },
+    'cl_nv_d3d11_sharing' : {
+        'number' : 4,
+        'flags' : { 'public' },
+        'url' : 'extensions/nv/cl_nv_d3d11_sharing.txt',
+    },
+    'cl_nv_d3d9_sharing' : {
+        'number' : 2,
+        'flags' : { 'public' },
+        'url' : 'extensions/nv/cl_nv_d3d9_sharing.txt',
+    },
+    'cl_nv_device_attribute_query' : {
+        'number' : 18,
+        'flags' : { 'public' },
+        'url' : 'extensions/nv/cl_nv_device_attribute_query.txt',
+    },
+    'cl_nv_pragma_unroll' : {
+        'number' : 19,
+        'flags' : { 'public' },
+        'url' : 'extensions/nv/cl_nv_pragma_unroll.txt',
+    },
+    'cl_qcom_android_native_buffer_host_ptr' : {
+        'number' : 32,
+        'flags' : { 'public' },
+        'url' : 'extensions/qcom/cl_qcom_android_native_buffer_host_ptr.txt',
+    },
+    'cl_qcom_ext_host_ptr' : {
+        'number' : 21,
+        'flags' : { 'public' },
+        'url' : 'extensions/qcom/cl_qcom_ext_host_ptr.txt',
+    },
+    'cl_qcom_ion_host_ptr' : {
+        'number' : 22,
+        'flags' : { 'public' },
+        'url' : 'extensions/qcom/cl_qcom_ion_host_ptr.txt',
+    },
+}
diff --git a/extensions/sortreg.py b/extensions/sortreg.py
new file mode 100755
index 0000000..15d27e3
--- /dev/null
+++ b/extensions/sortreg.py
@@ -0,0 +1,7 @@
+#!/usr/bin/python3
+
+import copy, os, re, string, sys
+import printreg
+import registry
+
+printreg.printreg(registry.registry, 'registry')
diff --git a/index.php b/index.php
index a4a2af8..9c77a82 100644
--- a/index.php
+++ b/index.php
@@ -372,114 +372,17 @@
 
 <h6> Enumerant and Extension Number Registry </h6>
 
-<p> <a href="api/cl.xml"> cl.xml </a> is the registry of reserved OpenCL API
-    enumerant ranges and of OpenCL extension numbers. </p>
+<p> <a href="xml/cl.xml"> cl.xml </a> is the registry of reserved OpenCL API
+    enumerant ranges. (Note that following this link will probably not
+    render sensibly in browsers, since the file is not entirely valid XML,
+    simply a manually updated placeholder.)</p>
 
 
 <h6> <a name="otherextspecs"></a>
      Extension Specifications</h6>
-<ol>
-<li value=1> <a href="extensions/khr/cl_khr_gl_sharing.txt">cl_khr_gl_sharing</a>
-</li>
-<li value=2> <a href="extensions/nv/cl_nv_d3d9_sharing.txt">cl_nv_d3d9_sharing</a>
-</li>
-<li value=3> <a href="extensions/nv/cl_nv_d3d10_sharing.txt">cl_nv_d3d10_sharing</a>
-</li>
-<li value=4> <a href="extensions/nv/cl_nv_d3d11_sharing.txt">cl_nv_d3d11_sharing</a>
-</li>
-<li value=5> <a href="extensions/khr/cl_khr_icd.txt">cl_khr_icd</a>
-</li>
-<li value=6> <a href="extensions/khr/cl_khr_d3d10_sharing.txt">cl_khr_d3d10_sharing</a>
-</li>
-<li value=7> <a href="extensions/amd/cl_amd_device_attribute_query.txt">cl_amd_device_attribute_query</a>
-</li>
-<li value=8> <a href="extensions/amd/cl_amd_fp64.txt">cl_amd_fp64</a>
-</li>
-<li value=9> <a href="extensions/amd/cl_amd_media_ops.txt">cl_amd_media_ops</a>
-</li>
-<li value=10> <a href="extensions/ext/cl_ext_migrate_memobject.txt">cl_ext_migrate_memobject</a>
-</li>
-<li value=11> <a href="extensions/ext/cl_ext_device_fission.txt">cl_ext_device_fission</a>
-</li>
-<li value=12> <a href="extensions/ext/cl_ext_atomic_counters_32.txt">cl_ext_atomic_counters_32</a>
-</li>
-<li value=13> <a href="extensions/ext/cl_ext_atomic_counters_64.txt">cl_ext_atomic_counters_64</a>
-</li>
-<li value=14> <a href="extensions/intel/cl_intel_dx9_media_sharing.txt">cl_intel_dx9_media_sharing</a>
-</li>
-<li value=15> <a href="extensions/amd/cl_amd_media_ops2.txt">cl_amd_media_ops2</a>
-</li>
-<li value=16> <a href="extensions/intel/cl_intel_thread_local_exec.txt">cl_intel_thread_local_exec</a>
-</li>
-<li value=17> <a href="extensions/nv/cl_nv_compiler_options.txt">cl_nv_compiler_options</a>
-</li>
-<li value=18> <a href="extensions/nv/cl_nv_device_attribute_query.txt">cl_nv_device_attribute_query</a>
-</li>
-<li value=19> <a href="extensions/nv/cl_nv_pragma_unroll.txt">cl_nv_pragma_unroll</a>
-</li>
-<li value=20> <a href="extensions/intel/cl_intel_device_partition_by_names.txt">cl_intel_device_partition_by_names</a>
-</li>
-<li value=21> <a href="extensions/qcom/cl_qcom_ext_host_ptr.txt">cl_qcom_ext_host_ptr</a>
-</li>
-<li value=22> <a href="extensions/qcom/cl_qcom_ion_host_ptr.txt">cl_qcom_ion_host_ptr</a>
-</li>
-<li value=23> <a href="extensions/intel/cl_intel_motion_estimation.txt">cl_intel_motion_estimation</a>
-</li>
-<li value=24> <a href="extensions/intel/cl_intel_accelerator.txt">cl_intel_accelerator</a>
-</li>
-<li value=25> <a href="extensions/amd/cl_amd_bus_addressable_memory.txt">cl_amd_bus_addressable_memory</a>
-</li>
-<li value=26> <a href="extensions/arm/cl_arm_get_core_id.txt">cl_arm_core_id</a>
-</li>
-<li value=27> <a href="extensions/arm/cl_arm_printf.txt">cl_arm_printf</a>
-</li>
-<li value=28> <a href="extensions/altera/cl_altera_live_object_tracking.txt">cl_altera_live_object_tracking</a>
-</li>
-<li value=29> <a href="extensions/altera/cl_altera_device_temperature.txt">cl_altera_device_temperature</a>
-</li>
-<li value=30> <a href="extensions/altera/cl_altera_compiler_mode.txt">cl_altera_compiler_mode</a>
-</li>
-<li value=31> <a href="extensions/intel/cl_intel_d3d11_nv12_media_sharing.txt">cl_intel_d3d11_nv12_media_sharing</a>
-</li>
-<li value=32> <a href="extensions/qcom/cl_qcom_android_native_buffer_host_ptr.txt">cl_qcom_android_native_buffer_host_ptr</a>
-</li>
-<li value=33> <a href="extensions/intel/cl_intel_advanced_motion_estimation.txt">cl_intel_advanced_motion_estimation</a>
-</li>
-<li value=34> <a href="extensions/intel/cl_intel_simultaneous_sharing.txt">cl_intel_simultaneous_sharing</a>
-</li>
-<li value=35> <a href="extensions/intel/cl_intel_subgroups.txt">cl_intel_subgroups</a>
-</li>
-<li value=36> <a href="extensions/intel/cl_intel_va_api_media_sharing.txt">cl_intel_va_api_media_sharing</a>
-</li>
-<li value=37> <a href="extensions/intel/cl_intel_egl_image_yuv.txt">cl_intel_egl_image_yuv</a>
-</li>
-<li value=38> <a href="extensions/arm/cl_arm_import_memory.txt">cl_arm_import_memory</a>
-</li>
-<li value=39> <a href="extensions/arm/cl_arm_non_uniform_work_group_size.txt">cl_arm_non_uniform_work_group_size</a>
-</li>
-<li value=40> <a href="extensions/arm/cl_arm_shared_virtual_memory.txt">cl_arm_shared_virtual_memory</a>
-</li>
-<li value=41> <a href="extensions/arm/cl_arm_thread_limit_hint.txt">cl_arm_thread_limit_hint</a>
-</li>
-<li value=42> <a href="extensions/intel/cl_intel_packed_yuv.txt">cl_intel_packed_yuv</a>
-</li>
-<li value=43> <a href="extensions/intel/cl_intel_required_subgroup_size.txt">cl_intel_required_subgroup_size</a>
-</li>
-<li value=44> <a href="extensions/img/cl_img_cached_allocations.txt">cl_img_cached_allocations</a>
-</li>
-<li value=45> <a href="extensions/img/cl_img_use_gralloc_ptr.txt">cl_img_use_gralloc_ptr</a>
-</li>
-<li value=46> <a href="extensions/img/cl_img_yuv_image.txt">cl_img_yuv_image</a>
-</li>
-<li value=47> <a href="extensions/intel/cl_intel_driver_diagnostics.txt">cl_intel_driver_diagnostics</a>
-</li>
-<li value=48> <a href="extensions/intel/cl_intel_subgroups_short.txt">cl_intel_subgroups_short</a>
-</li>
-<li value=49> <a href="extensions/intel/cl_intel_planar_yuv.txt">cl_intel_planar_yuv</a>
-</li>
-<li value=50> <a href="extensions/intel/cl_intel_device_side_avc_motion_estimation.txt">cl_intel_device_side_avc_motion_estimation</a>
-</li>
-</ol>
+
+<?php include("extensions/clext.php"); ?>
+
 <?php include_once("../../assets/static_pages/khr_page_bottom.php"); ?>
 </body>
 </html>
diff --git a/api/cl.xml b/xml/cl.xml
similarity index 98%
rename from api/cl.xml
rename to xml/cl.xml
index 602a042..52a1a9a 100644
--- a/api/cl.xml
+++ b/xml/cl.xml
@@ -1107,6 +1107,12 @@
     </enums>
 
     <!-- SECTION: OpenCL extension interface definitions (TBD) -->
+    <!-- NOTE: extension numbers are now assigned from
+         ../extensions/registry.py - see ../README.adoc. It is no longer
+         necessary to reserve extension names and numbers here. If we ever
+         start defining OpenCL interfaces in cl.xml, the extension tags
+         below would be expanded to refer to enums and APIs defined by that
+         extension, like the OpenGL gl.xml does. -->
     <extension number="1" name="cl_khr_gl_sharing"/>
     <extension number="2" name="cl_nv_d3d9_sharing"/>
     <extension number="3" name="cl_nv_d3d10_sharing"/>
@@ -1157,5 +1163,7 @@
     <extension number="48" name="cl_intel_subgroups_short"/>
     <extension number="49" name="cl_intel_planar_yuv"/>
     <extension number="50" name="cl_intel_device_side_avc_motion_estimation"/>
-        <!-- Next free extension number is assigned sequentially here -->
+    <!-- NOTE: extension numbers are now assigned from
+         ../extensions/registry.py - see ../README.adoc. It is no longer
+         necessary to reserve extension names and numbers here. -->
 </registry>