Download Source Write Comment. And does this follow the specification or the actual implementation? As I understand it Malbolge's interpreter reverses two of the instructions. My programming method uses many "NOP" intructions, that is why the pattern will occur corresponding to the specification of Malbolge.
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In this beginner's tutorial, we will write a simple non-terminating cat program in Malbolge. This tutorial is organized as follows. At first, a cat program written in the assembly language HeLL is explained in detail. Afterwards, we translate the cat program into Malbolge code manually, using the Malbolge pages of Lou Scheffer and a ternary number system calculator.
Hint: This tutorial is being revised at the moment. Please, don't be surprised by abruptly formatting change during the tutorial. Please read the Malbolge language definition.
It is not necessary that you have understood everything or learned it by heart. However, you may need to lookup some details of the language definition at certain times during this tutorial by your own.
There are two types of techniques to write Malbolge programs. The first technique is for writing programs that simply print out some text and terminate afterwards.
As you see, capabilities of this technique are very limited. There are even some generators for this task. The second technique is suited for writing complex Malbolge programs, i. If this technique is used, the programmer starts to create a Malbolge program under the assumption that every memory cell of the virtual Malbolge machine can be initialized with completely arbitrary values on startup.
From the language description, you know that this assumption is not true for Malbolge. Thus, in a second step, the programmer or an automated Malbolge assembler like LMAO generates Malbolge code that does nothing else than writing the required values into the corresponding memory cells.
LAL is the older one, created by some really cool Japanese researchers who were the first who ever really programmed in Malbolge. However, back in , a precise specification of LAL has not been available publically this has changed in the meantime.
That was the reason for creating HeLL. Both languages introduce labels, so that the programmer doesn't need to use ternary memory addresses all the time, and some mnemonic for pure Malbolge instructions e. Jmp for i. That's almost all these assembly languages do, so they are still a lot of Malbolge.
This tutorial starts to teach you HeLL, because it's much easier to understand than pure Malbolge. The second part of the tutorial covers the manual translation of HeLL to Malbolge. If you struggle with understanding this tutorial, please don't hesitate to mail me your questions. In Malbolge, code and data are stored together in the same memory. However, when writing Malbolge programs, it makes sense to distinguish between memory cells that are actually used for the code and those that are used for data.
In HeLL , the words. CODE and. DATA are used to define the corresponding sections. All code and all data within these sections must be assigned to a label. For the code section , it is important to be aware of the fact that Malbolge instructions are cyclic self-modifying. This kind of modification takes place after execution of an instruction and is often called encryption. In HeLL , a cycle can be specified by all of its components, separated by slashes each.
After its second encryption , it is turned into a Nop instruction again, and so on. It is not possible to build every cycle in Malbolge. If impossible cycles occur, the Malbolge assembler will throw an error.
More information about valid cycles and how to find them will be given later in this tutorial. If no cycle is specified, the Malbolge assembler will choose an arbitrary cycle that start with the given instruction. Below, you can find the entire cat program written in HeLL. The actual program logic appears in the data section. The debugger can be started form the menu bar. The yellow arrow points at the memory position the virtual Malbolge machine's data register D is pointing to.
In the code section , the current position of each instruction cycle is marked bold. At program start, this will always be the first instruction of each cycle.
Thus, the position of the C register cannot be marked in the debugger yet. Starting with the next step, the C register's position will be indicated by a green arrow. We can see the state of the virtual Malbolge machine's registers and specific memory cells at the right side. This contradicts the value displayed at the right side of the window.
However, the value on the right side is the real one. The reason is that, whenever a HeLL program is assembled to Malbolge, every reference is decremented by one automatically. The reason for this strange behaviour is as follows. Recall how an instruction in Malbolge is executed. The instruction at the C register is executed.
The instruction at the C register is encrypted. Both, the registers C and D are incremented by one. Note that the encryption is performed between these two steps. The Jmp command is not encrypted, but the command before the destination defined in the HeLL code.
In order to save the user from decrementing every jump address again and again, the LMAO Malbolge assembler performs the decrement by one automatically. Since the D register behaves analogously during a MovD instruction, unexceptional every reference is decremented by one by the Malbolge assembler automatically. The value of the A register is not defined when the execution of a HeLL program starts. Thus, we should never read from the A register until we have written a value into it using the Rot or In instruction, but not the Opr instruction.
This behavior may change for future versions of LMAO , so we must not rely on it. Let us execute one single step of the program now. Now we can observe how these values have changed. Now, the code register C is pointing at the In instruction. The D register has been incremented and is pointing now to a memory cell with undefined content, which is indicated by?
During the next step, the program will execute the In instruction and thus read one byte of user input. We have just written the word "foo". Now we can execute the next step that will load the character 'f' of our input into the A register. As expected, the A register holds the value 'f' ternary 0t now.
Also, the instruction In has been modified, so that the cycle's position is now at the first Nop instruction it is highlighted by boldface in the screenshot above. The C and D registers have been incremented. At the moment, the instruction is in a " destroyed " state, because the active instruction of its cycle is the Nop command, but not the MovD command. Recall that LMAO always decrements references by one. Let's figure out why this restores the instruction.
The active instruction of the preceeding instruction cycle has changed from Nop to MovD , as indicated by boldface. Why did this happen? Recall that, whenever the Malbolge interpreter has executed an instruction, the instruction that is pointed to by the C register is modified.
This happens before the C and D registers are incremented. For the Jmp instruction, the timing is as follows. At first, the C register is set to the new position. Then the command at the new C register's position is modified.
Finally, the C and D registers are incremented. Restoring a 2- cycle instruction by using the Jmp command in this way is an essential technique when writing HeLL or, respectively, Malbolge programs. Because both registers will be incremented after execution of the instruction, the D register will contain the address of the ENTRY label after the next step. There you go! The virtual Malbolge machine is nearly in its initial state again.
You can imagine how things will go on. In the subsequent pass, the character 'f' stored in the A register will be printed out. After a few more passes, the next character will be read. And so on ad nauseam. We will manually translate the HeLL cat program into Malbolge now. This makes sense for simple programs, because this way the code will become more succinct than the code generated by LMAO.
And, even more important, this is a great opportunity to increase your knowledge about Malbolge and how LMAO works. DATA section accordingly. This modification makes the construction of Malbolge code easier. This is due to the fact that in Malbolge, memory cells can be initialized with a few values directly.
Malbolge: an Esoteric Programming Language
Malbolge, an esoteric programming language is named after the 8th circle of hell in Dante's Inferno. It was so difficult to understand. Even it's creator didn't write a single program in it! The first Malbolge program was created after two years of it's introduction.
Malbolge Tutorial – Learning Malbolge
Malbolge is an esoteric programming language invented by Ben Olmstead in The language is designed to be as complex as possible for writing programs. On August 17, , Tomasz Vegzhanowski wrote a generator of programs that output given lines. However, the programs obtained in this way are longer than the Juhas programs.
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It was invented by Ben Olmstead in The intention was to create a language that would make writing programs as hard as possible. The second most significant person in the history of the language is Lou Scheffer who saved the original interpreter and specification after the original site stopped functioning, did a research on cryptanalysis of the language, created a program which copies its input into its output and offered a general strategy of writing programs in Malbolge as well as some thoughts on its Turing-completeness. Malbolge virtual machine works in ternary system.
It was specifically designed to be almost impossible to use, via a counter-intuitive 'crazy operation', base-three arithmetic, and self-altering code. Despite this design, it is possible to write useful Malbolge programs. Malbolge was so difficult to understand when it arrived that it took two years for the first Malbolge program to appear. Indeed, the author himself has never written a single Malbolge program. Later, Lou Scheffer posted a cryptanalysis of Malbolge and provided a program to copy its input to its output.
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