Merge pull request #255 from EhsanKhodadad/patmos

Patmos docs updated to reflect lf-lang/lingua-franca#2383

Author: lhstrh

docs/embedded/patmos.mdx

@@ -7,101 +7,64 @@ Lingua Franca's C-runtime supports [Patmos](https://github.com/t-crest/patmos),
 a bare-metal execution platform that is optimized for time-predictable execution.
 The time-predictability aspect of Patmos makes it easier to obtain a worst-case
 execution time (WCET) for reactions.
+## Prerequisites
+- Linux or macOS development system. (use WSL on Windows)
+- DE2-115 Development Kit, which is equipped with Altera Cyclone IV FPGA (optional)
+### Getting Started
+To know how to install the toolchain for building Patmos, read the Patmos project's readme at https://github.com/t-crest/patmos or study the sixth chapter of its handbook available here: [Patmos Reference Handbook](http://patmos.compute.dtu.dk/patmos_handbook.pdf)
+### Compiling and Running Lingua Franca codes
+Patmos can run in an FPGA, but there are also two simulators available:
+
+1. `pasim`: a software ISA simulator that is written in C++.
+2. `patemu`: a cycle-accurate hardware emulator generated from the hardware description.
+
+Consider the following simple LF program inside the HelloPatmos.lf file located in `test/C/src/patmos/HelloPatmos.lf`: 
+```lf-c
+target C {
+	platform: "Patmos",
+	single-threaded: true,
+	build-type: Debug, 
+}
 
-### Compiling and Running Reactors
-Patmos can run in an FPGA, but there are also two
-simulators available:
-
-1. `pasim` a software ISA simulator that is written in C++.
-2. `patemu` a cycle-accurate hardware emulator generated from the hardware description.
-
-To execute reactions on Patmos, the [Patmos toolchain](https://github.com/t-crest/patmos) needs
-to be installed. The web page contains a quick start, detailed information including how to
-perform WCET analysis is available in the
-[Patmos Reference Handbook](http://patmos.compute.dtu.dk/patmos_handbook.pdf).
-
-To execute the "hello world" reactor on Patmos use the LF compiler to generate the C code.
-Compile the reactor with the Patmos compiler (in `src-gen`):
-
-    patmos-clang Minimal.c -o Minimal.elf
+main reactor {
+	reaction(startup) {=
+		printf("Hello World!\n");
+	=}
+}
+  
 
-The reactor can be executed on the SW simulator with:
+```
+You can generate C code using `lfc HelloPatmos.lf` command in the above folder:
 
-    pasim Minimal.elf
+```
+cd test/C/src/patmos/
+lfc HelloPatmos.lf
+```
 
-As Patmos is a bare metal runtime that has no notion of calendar time, its start time
-is considered the epoch and the following output will be observed:
+If there is no error after making, an executable file must be generator inside `src-gen/patmos/HelloPatmos` folder. Then, the reactor can be executed on the SW simulator with the following command:
 
 ```
-Start execution at time Thu Jan  1 00:00:00 1970
-plus 640000 nanoseconds.
-Hello World.
-Elapsed logical time (in nsec): 0
-Elapsed physical time (in nsec): 3970000
+cd ../../src-gen/patmos/HelloPatmos/build
+pasim HelloPatmos
+```
+After executing the above command, the following lines must be printed.
+```
+Hello World!
+---- Elapsed logical time (in nsec): 0
+---- Elapsed physical time (in nsec): 770,000
 ```
 
 The reactor can also be executed on the hardware emulator of Patmos:
 
-    patemu Minimal.elf
-
-This execution is considerably slower than the SW simulator, as the concrete hardware
-of Patmos is simulated cycle-accurate.
-
-### Worst-Case Execution Time Analysis
-
-Following example is a code fragment from
-[Wcet.lf](https://github.com/lf-lang/lingua-franca/blob/master/xtext/org.icyphy.linguafranca/src/test/C/src/Wcet.lf).
-
-```lf-c
-reactor Work {
-    input in1: int;
-    input in2: int;
-    output out:int;
-    reaction(in1, in2) -> out {=
-    	int ret;
-    	if (in1 > 10) {
-    		ret = in2 * in1;
-    	} else {
-    		ret = in2 + in1;
-    	}
-        lf_set(out, ret);
-    =}
-}
+```
+patemu HelloPatmos
 ```
 
-We want to perform WCET analysis of the single reaction of the Work reactor.
-This reaction, depending on the input data, will either perform a multiplication,
-which is more expensive in Patmos, or an addition. The WCET analysis shall consider
-the multiplication path as the worst-case path. To generate the information for
-WCET analysis by the compiler we have to compile the application as follows:
-
-    patmos-clang -O2 -mserialize=wcet.pml Wcet.c
-
-We investigate the C source code `Wcet.c` and find that the reaction we
-are interested is named `reaction_function1`. Therefore, we invoke WCET analysis
-as follows:
-
-    platin wcet -i wcet.pml -b a.out -e reaction_function1 --report
-
-This results in following report:
+This execution is considerably slower than the SW simulator, as the concrete hardware
+of Patmos is simulated cycle-accurate. Here is a sample of its output:
 
 ```
-...
-[platin] INFO: Finished run WCET analysis (platin)          in 62 ms
-[platin] INFO: best WCET bound: 242 cycles
----
-- analysis-entry: reaction_function1
-  source: platin
-  cycles: 242
-...
+Hello World!
+---- Elapsed logical time (in nsec): 0
+---- Elapsed physical time (in nsec): 3,459,000
 ```
-
-The analysis gives the WCET of 242 clock cycles for the reaction,
-which includes clock cycles for data cache misses.
-Further details on the WCET analysis
-tool `platin` and e.g., how to annotate loop bounds can be found in the
-[Patmos Reference Handbook](http://patmos.compute.dtu.dk/patmos_handbook.pdf).
-
-Note, that the WCET analysis of a reaction does only include the code of the
-reaction function, not the cache miss cost of calling the function from
-the scheduler or the cache miss cost when returning to the scheduler.