Abstract-VM

42 Abstract VM project in the C++/OOP branch

Interpreter for low level assembly-like language for a stack based calculator

Installation

make

Usage

./avm file

Reads contents of file if given as argument-- otherwise reads from stdin

Instructions are define thusly:

s := INSTR [SEP INSTR]* #

INSTR :=
	  push VALUE
	  | pop
	  | dump
	  | assert VALUE
	  | add
	  | sub
	  | mul
	  | div
	  | mod
	  | print
	  | exit

VALUE :=
	  int8(N)
	  | int16(N)
	  | int32(N)
	  | float(Z)
	  | double(Z)

N := [-]?[0..9]+

Z := [-]?[0..9]+.[0..9]+

SEP := '\n'+

Command	Description	Example
push	pushes argument of type v to top of stack	push int8(42)
pop	pops and deletes top of stack	pop
dump	prints every value on the stack	dump
assert	asserts that the top value is equal to the one given	assert float(42.42)
add	unstacks and adds the top two elements and stacks result	add
sub	unstacks and subtracts the top two elements and stacks result	sub
mul	unstacks and multiplies the top two elements and stacks result	mul
div	unstacks and divides the top two elements and stacks result	div
mod	unstacks and finds the modulus of the top two elements and stacks result	mod
print	asserts that top element is int8 and prints value to standard out	print
exit	terminates execution. Every program must have an 'exit' command	exit
;;	EOF for stdin. Every program reading from stdin must end with this	;;
;	comment. All input after ; is ignored unless it signals EOF	add ; comment