10-challenge

Challenge 10

The elf programmers are creating a small magical assembler to control the machines in Santa Claus's workshop.

To assist them, we will implement a simple interpreter that supports the following magical instructions:

• MOV x y: Copies the value x (which can be a number or the content of a register) into register y.
• INC x: Increments the content of register x by 1.
• DEC x: Decrements the content of register x by 1.
• JMP x y: If the value in register x is 0, then jumps to the instruction at index y and continues executing the program from there.

Expected behavior:

• If an attempt is made to access, increment, or decrement a register that has not been initialized, the default value 0 will be used.
• The jump with JMP is absolute and goes to the exact index indicated by y.
• Upon completion, the program should return the content of register A. If A did not have a defined value, it returns undefined.

Note

Registers that have not been previously initialized are initialized to 0.

const instructions = [
	'MOV -1 C', // Copies -1 to register 'C'.
	'INC C', // Increments the value of register 'C'.
	'JMP C 1', // Jumps to the instruction at index 1 if 'C' is 0.
	'MOV C A', // Copies register 'C' to register 'A'.
	'INC A', // Increments the value of register 'A'.
]

compile(instructions) // Expected result: 2

/**
 * Step-by-step execution:
 *  0: "MOV -1 C" => The register C receives the value -1.
 *  1: "INC C"    => The register C becomes 0.
 *  2: "JMP C 1"  => C is 0, jumps to the instruction at index 1.
 *  1: "INC C"    => The register C becomes 1.
 *  2: "JMP C 1"  => C is 1, the instruction is ignored.
 *  3: "MOV C A"  => Copies register C to A. Now A is 1.
 *  4: "INC A"    => The register A becomes 2.
 */

Solutions

• Python
• JavaScript
• TypeScript

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