This project is an implementation of a P-machine, a theoretical stack-based virtual machine commonly used in compiler design and computer science education. The P-machine executes a sequence of instructions, manipulating a stack and performing various operations defined by opcodes.
Stack-based virtual machine Implemented opcodes for operations like literal push, return, load, store, call, increment, jump, jump conditional, and system calls Reads instructions from a file and executes them Supports basic arithmetic and control flow operations Simple demonstration of a stack-based execution environment Usage:
Compile the source code. Run the executable with a file containing P-machine instructions. gcc vm.c ./a.out myinput.txt Example Instruction File:
7 0 45 // Jump to instruction at index 45 if the top of the stack is less than 0 7 0 6 // Jump to instruction at index 6 if the top of the stack is less than 0 6 0 4 // Increment the stack pointer by 4 1 0 4 // Push literal 4 onto the stack 1 0 3 // Push literal 3 onto the stack 2 0 3 // Return from procedure 4 1 4 // Store the value at the top of the stack in the stack location at offset 4 from 1 lexicographical level down 1 0 14 // Push literal 14 onto the stack 3 1 4 // Load value from the stack location at offset 4 from 1 lexicographical level down 2 0 7 // Jump to instruction at index 7 8 0 39 // Jump to instruction at index 39 if the top of the stack is 0 1 0 7 // Push literal 7 onto the stack 7 0 42 // Jump to instruction at index 42 if the top of the stack is less than 0 1 0 5 // Push literal 5 onto the stack 2 0 0 // Return from procedure 6 0 5 // Increment the stack pointer by 5 9 0 2 // System call to read an integer as a character value from standard input 5 0 6 // Jump to instruction at index 6 if the top of the stack is not 0 9 0 1 // System call to output the value at the top of the stack to standard output as a character 9 0 3 // System call to halt the P-machine