GoStack

A Stack-Based Virtual Machine built in Go.

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Introduction

GoStack is a virtual machine, but it's a little bit different from my other ones.

This is based on a stack, which is modified using some operations.

Operations

Operation	Value	Description
PUSH	1	Adds arg to stack
ADD	2	Sums and deletes two last stack elements and appends result
SUB	3	Substracts and deletes two last stack elements and appends result
MUL	4	Multiplies and deletes two last stack elements and appends result
DIV	5	Divides (if b!=0) and deletes two last stack elements and appends result
OUT	6	Outputs the stack
JMP	7	Jumps to arg
JNZ	8	Jumps to arg if last element of stack != 0
JIZ	9	Jumps to arg if last element of stack == 0
POP	10	Deletes last element of stack
DUP	11	Duplicates last element of stack
COUT	12	Outputs to terminal the last stack item as ascii code
EQ	13	Pops two values and pushes 1 (true) if they are equal, otherwise 0 (false)
NEQ	14	Pops two values and pushes 1 if they are not equal, otherwise 0
LT	15	Pops two values and pushes 1 if the first value is less than the second
LTE	16	Pops two values and pushes 1 if the first value is less than or equal to the second
GT	17	Pops two values and pushes 1 if the first value is greater than the second
GTE	18	Pops two values and pushes 1 if the first value is greater than or equal to the second
AND	19	Pops two values, performs a bitwise AND operation, and pushes the result
OR	20	Pops two values, performs a bitwise OR operation, and pushes the result
XOR	21	Pops two values, performs a bitwise exclusive OR operation, and pushes the result
NOT	22	Pops the top value, inverts all its bits, and pushes the result
SHL	23	Pops a value and a shift count, shifts the value bits left, and pushes the result
SHR	24	Pops a value and a shift count, shifts the value bits right, and pushes the result

Error management

At the moment, there are two possible errors:

• Not enough args in stack
• b == 0 in division

Errors are treated as intentional, so they are just ignored.

Example: sum 5 and 3

program.gosb should be:

PUSH, 5,
PUSH, 3,
ADD,
OUT,

Future Operations

Memory & Pointers

• LOAD = 13: Reads data from a specific memory address and pushes it onto the data stack.
• STORE = 14: Pops a value from the data stack and writes it to a specific memory address.
• LOADI = 15: Indirect load. Pops an address from the stack, reads the value from that address, and pushes it.
• STOREI = 16: Indirect store. Pops an address and a value from the stack, then writes the value to that address.

Advanced Stack Manipulation

• SWAP = 23: Exchanges the positions of the top two items on the stack.
• OVER = 25: Copies the second item on the stack and pushes it to the top.
• ROT = 26: Rotates the top three items on the stack, moving the third item to the top.
• PICK = 27: Copies the n-th item down the stack (where n is popped from the top) and pushes it to the top.

Functions & Return Stack

• CALL = 28: Pushes the current execution pointer to the return stack and jumps to a function address.
• RET = 29: Pops the return address from the return stack and jumps back to resume previous execution.
• RUSH = 30: Pops a value from the main data stack and pushes it directly onto the return stack.
• RPOP = 31: Pops a value from the return stack and pushes it onto the main data stack.

System & I/O

• IN = 38: Reads raw numerical data or hardware signal input and pushes it onto the stack.
• CIN = 39: Reads a single character from the standard input stream and pushes its character code.
• HALT = 40: Immediately stops all execution of the virtual machine program.
• TIME = 41: Pushes the current system clock time or tick count onto the stack. (TIME, {1: Hour, 2: Minutes, 3:Second},)

Math Extensions

• MOD = 42: Pops two values, calculates the remainder of their division, and pushes the result.
• INC = 43: Adds 1 directly to the top value on the stack.
• DEC = 44: Subtracts 1 directly from the top value on the stack.

Future Idea

• I would like to make (another) programming lanugage, but this time, using GoStack instead of LLVM. You can find it in my repo Salt
• We could make substacks, simpler secondary stack, with only SPUSH, SPOP and SRUN.
  • SPUSH pushes to actual substack (main -> current substack)
  • SPOP pops from actual substack (current substack -> main)
  • SRUN executes a command that only requieres one argument (like COUT) and executes it at all the substack Also, wo would need these:
  • SCRT creates a new substack with an ID
  • SGO goes to that substack
  • SDROP deletes the substack