Implement the push and pall opcodes.
The push opcode
The opcode push pushes an element to the stack.
Usage: push
where is an integer
if is not an integer or if there is no argument given to push, print the error message L<line_number>: usage: push integer, followed by a new line, and exit with the status EXIT_FAILURE
where is the line number in the file
You won't have to deal with overflows. Use the atoi function
The pall opcode
The opcode pall prints all the values on the stack, starting from the top of the stack.
Usage pall
Format: see example
If the stack is empty, don't print anything
1. pint
mandatory
Implement the pint opcode.
The pint opcode
The opcode pint prints the value at the top of the stack, followed by a new line.
Usage: pint
If the stack is empty, print the error message L<line_number>: can't pint, stack empty, followed by a new line, and exit with the status EXIT_FAILURE
2. pop
mandatory
Implement the pop opcode.
The pop opcode
The opcode pop removes the top element of the stack.
Usage: pop
If the stack is empty, print the error message L<line_number>: can't pop an empty stack, followed by a new line, and exit with the status EXIT_FAILURE
3. swap
mandatory
Implement the swap opcode.
The swap opcode
The opcode swap swaps the top two elements of the stack.
Usage: swap
If the stack contains less than two elements, print the error message L<line_number>: can't swap, stack too short, followed by a new line, and exit with the status EXIT_FAILURE
4. add
mandatory
Implement the add opcode.
The add opcode
The opcode add adds the top two elements of the stack.
Usage: add
If the stack contains less than two elements, print the error message L<line_number>: can't add, stack too short, followed by a new line, and exit with the status EXIT_FAILURE
The result is stored in the second top element of the stack, and the top element is removed, so that at the end:
The top element of the stack contains the result
The stack is one element shorter
5. nop
mandatory
Implement the nop opcode.
The nop opcode
The opcode nop doesn't do anything.
Usage: nop
6. sub
#advanced
Implement the sub opcode.
The sub opcode
The opcode sub subtracts the top element of the stack from the second top element of the stack.
Usage: sub
If the stack contains less than two elements, print the error message L<line_number>: can't sub, stack too short, followed by a new line, and exit with the status EXIT_FAILURE
The result is stored in the second top element of the stack, and the top element is removed, so that at the end:
The top element of the stack contains the result
The stack is one element shorter
7. div
#advanced
Implement the div opcode.
The div opcode
The opcode div divides the second top element of the stack by the top element of the stack.
Usage: div
If the stack contains less than two elements, print the error message L<line_number>: can't div, stack too short, followed by a new line, and exit with the status EXIT_FAILURE
The result is stored in the second top element of the stack, and the top element is removed, so that at the end:
The top element of the stack contains the result
The stack is one element shorter
If the top element of the stack is 0, print the error message L<line_number>: division by zero, followed by a new line, and exit with the status EXIT_FAILURE
8. mul
#advanced
Implement the mul opcode.
The mul opcode
The opcode mul multiplies the second top element of the stack with the top element of the stack.
Usage: mul
If the stack contains less than two elements, print the error message L<line_number>: can't mul, stack too short, followed by a new line, and exit with the status EXIT_FAILURE
The result is stored in the second top element of the stack, and the top element is removed, so that at the end:
The top element of the stack contains the result
The stack is one element shorter
9. mod
#advanced
Implement the mod opcode.
The mod opcode
The opcode mod computes the rest of the division of the second top element of the stack by the top element of the stack.
Usage: mod
If the stack contains less than two elements, print the error message L<line_number>: can't mod, stack too short, followed by a new line, and exit with the status EXIT_FAILURE
The result is stored in the second top element of the stack, and the top element is removed, so that at the end:
The top element of the stack contains the result
The stack is one element shorter
If the top element of the stack is 0, print the error message L<line_number>: division by zero, followed by a new line, and exit with the status EXIT_FAILURE
10. comments
#advanced
Every good language comes with the capability of commenting. When the first non-space character of a line is #, treat this line as a comment (don't do anything).
11. pchar
#advanced
Implement the pchar opcode.
The pchar opcode
The opcode pchar prints the char at the top of the stack, followed by a new line.
Usage: pchar
The integer stored at the top of the stack is treated as the ascii value of the character to be printed
If the value is not in the ascii table (man ascii) print the error message L<line_number>: can't pchar, value out of range, followed by a new line, and exit with the status EXIT_FAILURE
If the stack is empty, print the error message L<line_number>: can't pchar, stack empty, followed by a new line, and exit with the status EXIT_FAILURE
12. pstr
#advanced
Implement the pstr opcode.
The pstr opcode
The opcode pstr prints the string starting at the top of the stack, followed by a new line.
Usage: pstr
The integer stored in each element of the stack is treated as the ascii value of the character to be printed
The string stops when either:
the stack is over
the value of the element is 0
the value of the element is not in the ascii table
If the stack is empty, print only a new line
13. rotl
#advanced
Implement the rotl opcode.
The rotl opcode
The opcode rotl rotates the stack to the top.
Usage: rotl
The top element of the stack becomes the last one, and the second top element of the stack becomes the first one
rotl never fails
14. rotr
#advanced
Implement the rotr opcode.
The rotr opcode
The opcode rotr rotates the stack to the bottom.
Usage: rotr
The last element of the stack becomes the top element of the stack
rotr never fails
15. stack, queue
#advanced
Implement the stack and queue opcodes.
The stack opcode
The opcode stack sets the format of the data to a stack (LIFO). This is the default behavior of the program.
Usage: stack
The queue opcode
The opcode queue sets the format of the data to a queue (FIFO).
Usage: queue
When switching mode:
The top of the stack becomes the front of the queue
The front of the queue becomes the top of the stack
16. Brainf*ck
#advanced
Write a Brainf*ck script that prints School, followed by a new line.
All your Brainf*ck files should be stored inside the bf sub directory
You can install the bf interpreter to test your code: sudo apt-get install bf
Read: Brainf*ck
17. Add two digits
#advanced
Add two digits given by the user.
Read the two digits from stdin, add them, and print the result
The total of the two digits with be one digit-long (<10)
18. Multiplication
#advanced
Multiply two digits given by the user.
Read the two digits from stdin, multiply them, and print the result
The result of the multiplication will be one digit-long (<10)
19. Multiplication level up
#advanced
Multiply two digits given by the user.
Read the two digits from stdin, multiply them, and print the result, followed by a new line
ABOUT MONTY
Monty
monty is an interpreter of Monty ByteCodes files, which is a scripting language just like Python.
About the Monty language
This is a language that contains specific instructions to manipulate data information (stacks or queues), where each instruction (called opcode) is sended per line. Files which contains Monty byte codes usually have the .m extension.
Example (file.m):
$ cat file.m
push 0
push 1
push 2
pall
push 3
push 4
pop
rotr
pall
rotl
queue
push 5
stack
push 5
$
Technologies
Interpreter was written with C language
C files are compiled using gcc 4.8.4
C files are written according to the C90 standard
Tested on Ubuntu 14.04 LTS
Usage
To compile all files:
$ gcc -Wall -Werror -Wextra -pedantic *.c -o monty
$
The synopsis of the interpreter is the following:
$ ./monty [filename]
$
To run the interpreter:
$ ./monty file.m
2
1
0
0
3
2
1
$
Features
Opcodes
monty executes the following opcodes:
Opcode Description
push Pushes an element to the stack
pall Prints all the values on the stack
pint Prints the value at the top of the stack
pop Removes the top element of the stack
swap Swaps the top two elements of the stack
queue Sets the format of the data to a queue (FIFO)
stack Sets the format of the data to a stack (LIFO)
nop Doesn't do anything
add Adds the top two elements of the stack
sub Subtracts the top element of the stack from the second top element of the stack
mul Multiplies the second top element of the stack with the top element of the stack
div Divides the second top element of the stack by the top element of the stack
mod Computes the rest of the division of the second top element of the stack by the top element of the stack
pchar Prints the char at the top of the stack
pstr Prints the string starting at the top of the stack
rotl Rotates the stack to the top
rotr Rotates the stack to the bottom
Comments, indicated with #, are not executed by the interpreter.
When a nonextistent opcode is passed, the interpreter prints an error message and stops:
$ cat errorfile.m
push 1
pint
pcx
$ ./monty errorfile.m
1
L3: unknown instruction pcx
Return value
When there is no errors, monty returns 0. Otherwise, returns 1