This is the story of my life so far: 68 years and counting.
Prequel: A Brief History of my Family in France
The story starts here
Previous episode: Part 64
I Discover the Pascal Programming Language
Ron, my Canadian officer friend, made me discover the Pascal programming language.
Pascal was created by Niklaus Wirth, a Swiss computer scientist, who published th manual for Pascal in 1970.
Niklaus Wirth in 1969
source: Wikipedia
Also, Ron made me discover Byte, a microcomputer magazine. I immediately bought a subscription.
We saw in one issue of Byte a commercial for a Pascal compiler, written by some guys in Windsor Junction, a small community less than 30 km from Halifax.
I Buy a Small Pascal Compiler that I Reverse Engineer
So, I bought a copy of this Pascal compiler. As I remember, the price was CAD$29.95, so not very expensive.
I started to write small toy programs using this Pascal compiler.
Soon, I was more interested in the compiler than in writing programs for it.
I rapidly discovered that the compiler was converting the Pascal sources into pseudo code, that is binary code for a virtual machine. This is very similar to what was being done at the time with UCSD Pascal and the UCSD p-system.
The executable program produces by the compiler included a copy of an interpreter. When running the program, the interpreter was reading the pseudo code an executing its instructions.
I decoded the interpreter to understand what each instruction of the pseudo code was doing.
I gave meaningful names for each pseudo code, such as "ADD" or "LOAD", and I wrote in Pascal what I called a "depseudocoder" to list the pseudo code of the compiler in something readable.
Like most Pascal compilers, this one was itself written in Pascal.
From the output of my depseudocoder, I tried to rewrite in Pascal the compiler, until I produced the exact same pseudo code of the compiler I had bought.
I had succeeded to reverse engineer the Pascal compiler.
I write my Own Pascal Compiler
The Pascal compiler that I had bought was only supporting a subset of the Pascal programming language.
For example, the numerical variables could only be integer, not floating point.
I had decided to write an improved compiler that would include several of the missing features in the compiler I had bought, in particular floating point arithmetic.
I was still using pseudo code, but I had completely changed the values of the codes so that nobody would accused me of having stolen the compiler, although that was in fact what I had done.
When my compiler was in good shape, probably at the beginning of 1982, I decided to create a small company and to sell my Pascal compiler all over the world.
Continue to Part 66
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Summary
Part 1 - Part 2 - Part 3 - Part 4 - Part 5 - Part 6 - Part 7 - Part 8
Part 9 - Part 10 - Part 11 - Part 12 - Part 13 - Part 14 - Part 15 - Part 16
Part 17 - Part 18 - Part 19 - Part 20 - Part 21 - Part 22 - Part 23 - Part 24
Part 25 - Part 26 - Part 27 - Part 28 - Part 29 - Part 30 - Part 31 - Part 32
Part 33 - Part 34 - Part 35 - Part 36 - Part 37 - Part 38 - Part 39 - Part 40
Part 41 - Part 42 - Part 43 - Part 44 - Part 45 - Part 46 - Part 47 - Part 48
Part 49 - Part 50 - Part 51 - Part 52 - Part 53 - Part 54 - Part 55 - Part 56
Part 57 - Part 58 - Part 59 - Part 60 - Part 61 - Part 62 - Part 63 - Part 64
