OpenCL works

Makefile_many

@@ -108,9 +108,11 @@ profile: clean set_profile_flags all run
 	cd '$(OUT_DIR)' && gprof -b '$(RUN_BNAME)' gmon.out | tee "$(RUN_BNAME).profile_out" | less
 
 run: all
-	@echo
 	cd $(OUT_DIR) && ./$(RUN_BNAME)
 
+time: all
+	cd $(OUT_DIR) && time -p ./$(RUN_BNAME)
+
 set_profile_flags:
 	$(eval PROFILE_FLAGS := -p -pg)
 	$(eval PROFILE_DEFINE := -DPROFILE)

Makefile_one

@@ -74,7 +74,7 @@ clean:
 	if [ ! '$(OUT_DIR)' = './'  ]; then \
 		rm -rf '$(OUT_DIR)' ;\
 	else \
-		rm -f *'$(OBJECT_EXT)' *'$(OUT_EXT)' *'$(TMP_EXT)' ;\
+		rm -f *'$(OBJ_EXT)' *'$(OUT_EXT)' *'$(TMP_EXT)' ;\
 	fi
 
 debug: clean set_debug_flags all

c/README.md

@@ -42,6 +42,7 @@
                 1. [_Static_assert](static_assert.c)
         1.  [Pointer](pointer.c)
             1. [void pointer](void_pointer.c)
+            1. [Pointer to int typecast](pointer_to_int.c)
             1. [NULL](null.c)
     1.  Branching
         1. [if](if.c)

c/inttypes_h.c

@@ -1,4 +1,5 @@
-/*# PRIxPTR
+/*
+# PRIxPTR
 */
 
 #include "common.h"
@@ -53,7 +54,25 @@ int main() {
     # Fixed size integer printf format
 
     # PRId16
+
+    # PRId32
+
+    # PRId64
+
+        Why not modify printf instead of adding those new macros?
+        http://stackoverflow.com/questions/1183679/why-werent-new-bit-width-specific-printf-format-option-strings-adoped-as-pa
+
+    # PRIu32
+
+        Unsigned versions.
     */
+    {
         printf("PRId16 = %s\n", PRId16);
+        printf("PRId32 = %s\n", PRId32);
+        printf("PRId64 = %s\n", PRId64);
+
+        /* Samplel usage:*/
+        printf("%" PRIx32 "\n", (uint32_t)0xFFFFFFFF);
+    }
 #endif
 }

c/operator.c

@@ -95,8 +95,8 @@ int main() {
             C first casts the integer type to a floating point type, then does
             the floating point operation.
 
-            Division by `0` leads to different problems, which are also different
-            on the floating point and integer cases.
+            Division by `0` is undefined behaviour. On Linux it raises SIGFPE. 
+            But note that handling the SIGFPE returns to just before the division. TODO check + example.
 
         # INT_MIN / -1
 

c/pointer.c

@@ -1,5 +1,5 @@
 /*
-# pointer
+# Pointer
 
     Pointers contain addresses of variables instead of the value.
 
@@ -38,7 +38,7 @@ int main() {
     float *fp = (float *)&i;
 
     /*
-    # single line multiple pointer declaration
+    # Single line multiple pointer declaration
 
         You must put an asterisk for each pointer, or they are not taken to be pointers!
 

c/pointer_to_int.c

@@ -0,0 +1,15 @@
+/*
+# Pointer to int typecasts
+
+    Implementation defined.
+
+    http://stackoverflow.com/questions/7677919/unexpected-sign-extension-of-int32-or-32bit-pointer-when-converted-to-uint64
+
+    TODO convert forward and back guaranteed equal?
+*/
+
+#include "common.h"
+
+int main() {
+    return EXIT_SUCCESS;
+}

c/signal.c

@@ -45,7 +45,8 @@ or specific operating systems
 
         Integer division by 1 / 0 may generate a `SIGFPE`.
 
-        TODO is 1 / 0 guaranteed to generate a `SIGFPE`?
+        1 / 0 is undefined behaviour. On x86, it generates a Divide Error,
+        which Linux delivers as a SIGFPE.
 
         TODO how to deal with it? it just keeps coming back time after time.
 

c/stdio_h.c

@@ -95,6 +95,8 @@ Returns a pointer to the start of that array.
 In case of any error, returns NULL.
 
 The entire file must fit into the memory avilable to the program.
+
+http://stackoverflow.com/questions/174531/easiest-way-to-get-files-contents-in-c
 */
 char *file_read(char *path) {
     FILE *fp;
@@ -596,7 +598,7 @@ int main() {
 
             - return `NULL` and set `errno`.
 
-        # Text IO vs # Binary IO
+        # Text IO vs Binary IO
 
             # Text vs binary for numerical types
 
@@ -845,7 +847,7 @@ int main() {
         */
     }
 
-    /* # applications */
+    /* # Applications */
     {
         {
             char path[] = TMPFILE("str_file");
@@ -879,13 +881,15 @@ int main() {
         }
 
         /*
-        Process a file #linewise.
+        # Linewise file processing
+
+            Process a file linewise.
 
-        Allows one to read files larger than RAM, suppposing that each line is smaller than RAM.
+            Allows one to read files larger than RAM, suppposing that each line is smaller than RAM.
 
-        glibc and C++ stdlib offer the `getline` function which does it.
+            glibc and C++ stdlib offer the `getline` function which does it.
 
-        There does not seem to be such a function in C! <http://stackoverflow.com/questions/3501338/c-read-file-line-by-line>
+            There does not seem to be such a function in C! http://stackoverflow.com/questions/3501338/c-read-file-line-by-line
         */
         {
             FILE* fp;

c/undefined-behaviour.md

@@ -33,6 +33,8 @@ Examples that explain both:
 
 Each implementation must document what it does but setting a fixed parameter.
 
+GCC has a list of its choices at: <https://gcc.gnu.org/onlinedocs/gcc/C-Implementation.html>
+
 E.g.: `sizeof(int)`
 
 The standard may put constraints on what is conforming.

c/void_pointer.c

@@ -51,27 +51,22 @@ int main() {
     This means that `sizeof(void)` is not possible, nor are pointer arithmetic operations.
     */
     {
-        /* it is however possible to get the size of a `void*` */
+        /* It is however possible to get the size of a `void*`. */
+        printf("sizeof (void*) = %zu\n", sizeof(void*));
 
-            printf("sizeof (void*) = %zu\n", sizeof(void*));
-
-        /* ERROR: invalid application of sizeof to void type */
-
-            /*vp = vp + 1;*/
+        /* ERROR: invalid application of sizeof to void type. */
+        /*vp = vp + 1;*/
     }
 
     /* int* to void*: */
-
-        vp = (void*)&i;
+    vp = (void*)&i;
 
     /* void* to int*: */
+    ip = (int*)vp;
 
-        ip = (int*)vp;
-
-    /* void* to int. GCC 4.8: cast from pointer to int of different size: */
-    /* `-Wpointer-to-int-cast */
-
-        /*i = (int)vp;*/
+    /* void* to int. */
+    /* WARN GCC 4.8: cast from pointer to int of different size: -Wpointer-to-int-cast */
+    /*i = (int)vp;*/
 
     /*
     Typecast to the bad type.

cpp/placement-new.cpp

@@ -0,0 +1,12 @@
+/*
+# Placement new
+
+    TODO
+
+    http://stackoverflow.com/questions/222557/what-uses-are-there-for-placement-new
+*/
+
+#include "common.hpp"
+
+int main() {
+}

gcc/128_bit_int.c

@@ -7,10 +7,10 @@
 
     https://gcc.gnu.org/onlinedocs/gcc-5.1.0/gcc/_005f_005fint128.html
 
-    Where it is supported:
-
     - http://stackoverflow.com/questions/3329541/does-gcc-support-128-bit-int-on-amd64
     - http://stackoverflow.com/questions/21886985/what-gcc-versions-support-the-int128-intrinsic-type
+
+    No hardware support it seems.
 */
 
 #include "common.h"

gdb/count_infinite.c

@@ -1,5 +1,7 @@
 /*
 To break interactively in the infinite loop, enter Ctrl + C.
+
+- http://stackoverflow.com/questions/8702658/gdb-how-do-i-pause-during-loop-execution
 */
 
 #include <stdio.h>

opencl/Makefile

@@ -0,0 +1 @@
+../Makefile_many

opencl/Makefile.bak

@@ -0,0 +1,9 @@
+.POSIX:
+
+.PHONY: all clean
+
+all:
+	gcc -std=c89 -o main.out main.c -lOpenCL
+
+clean:
+	rm hello

opencl/Makefile_params

@@ -0,0 +1 @@
+LIBS := -lm -pthread -lOpenCL

opencl/README.md

@@ -1,17 +1,12 @@
 # OpenCL
 
-OpenCL is an open standard language which models CPU GPU computing.
-
-It is similar to C, containing some extra keywords to model the CPU GPU world, and leaving out a few C features which GPUs cannot yet do very well.
-
-As of 2013 its major concurrent is CUDA, which NVIDIA proprietary. Current NVIDIA do support both CUDA and OpenCL.
-
-The OpenCL standard in maintained by the Khronos Group, the same guys who maintain OpenGL. They are an industry consortium.
-
-OpenCL, like any other language has versions. As of 2013 the latest version is OpenCL 2.0 released in preview (unstable) as of Jul 2013.
-
-## Install
-
-The first step is to get you GPU working. Good luck on that, specially if you are on Linux =)
-
-Next, you will need an SDK developed by the GPU vendor. There is no fixed standard assembly language for GPUs, in part because GPUs are changing very fast, so vendors do not want to get tied down to an interface. Therefore, the only way to go is to pass through the vendor SDK which should implement OpenCL.
+1.  [Getting started](getting-started.md)
+1.  Examples
+    1.  [min](min.c)
+    1.  [hello_world](hello_world.c)
+1.  Theory
+    1.  [Introduction](introduction.md)
+    1.  [Concepts](concepts.md)
+    1.  [clinfo](clinfo.md)
+    1.  [Bibliography](bibliography.md)
+    1.  [TODO](TODO.md)

opencl/TODO.md

@@ -0,0 +1,3 @@
+# TODO
+
+1. Compare speeds of `CL_DEVICE_TYPE_GPU` and `CL_DEVICE_TYPE_CPU`.

opencl/bibliography.md

@@ -0,0 +1,6 @@
+# Bibliography
+
+- Khronos standards: <https://www.khronos.org/registry/cl/>
+- <http://developer.amd.com/tools-and-sdks/opencl-zone/opencl-resources/>
+- <http://www.fixstars.com/en/opencl/book/OpenCLProgrammingBook>
+- The specifications of your hardware, e.g. <http://www.nvidia.com/object/nvs_techspecs.html>

opencl/clinfo.md

@@ -0,0 +1,5 @@
+# clinfo
+
+`glxinfo` for OpenCL:
+
+    sudo clinfo

opencl/concepts.md

@@ -0,0 +1,15 @@
+# Concepts
+
+## Platform
+
+TODO what is a platform?
+
+<http://stackoverflow.com/questions/3444664/does-any-opencl-host-have-more-than-one-platform>
+
+## Compute unit
+
+TODO vs core? Each compute unit has a number of cores it seems: 
+
+## Work group
+
+TODO

opencl/getting-started.md

@@ -0,0 +1,19 @@
+# Getting started
+
+## NVIDIA
+
+On Ubuntu 15.10 with an NVIDIA NVS 5400M, Lenovo T430:
+
+    sudo apt-get install nvidia-352 nvidia-352-dev nvidia-prime
+    sudo ln -s /usr/include/nvidia-352/GL /usr/local/include
+    sudo ln -s /usr/lib/x86_64-linux-gnu/libOpenCL.so.1 /usr/local/lib/libOpenCL.so
+
+Then compile with:
+
+	gcc -o main main.c -lOpenCL
+
+Notes:
+
+- find your GPU model: <http://askubuntu.com/questions/72766/how-do-i-find-out-the-model-of-my-graphics-card>
+- test that the driver is working: <http://askubuntu.com/questions/68028/how-do-i-check-if-ubuntu-is-using-my-nvidia-graphics-card>
+- do not install the `nvidia-current` package. It is old. Either `apt-cache search nvidia` and get the latest one, or use `software-properties-gtk` "Additional Drivers" tab.