StackMachine

This project is a modded Stack Machine simulator developed for INF01112 - Architecture and Organization of Computers II class at UFRGS.

Made by Eduardo Luis Marques, Henrique Utzig and Pedro Afonso Klein.

---

Setup and execution

1. Build: execute Make on root directory (GCC required)

make

2. run: run executable on terminal

stackMachine

or with optional parameters, where -d is debug mode and -v is verbose mode

stackMachine filePath_to_execute -d -v

---

Stack Machine Characteristic

• WORD size: 16 bits
• Stack size: 128 WORDS
• Registers (1 WORD):
  • R: register for all arithmetic and logic operations result
  • M: register for operations STORE and LOAD
• Flags:
  • ZF: zero flag
  • NF: negative flag
• Control variables:
  • SP: stack pointer
  • PC: program count

---

Instruction Set

• Arithmetic:
  • ADD: R = stack[SP] + stack[SP - 1]
  • SUB: R = stack[SP] - stack[SP - 1]
  • MUL: R = stack[SP] * stack[SP - 1]
  • DIV: R = stack[SP] / stack[SP - 1]
  • MOD: R = stack[SP] mod stack[SP - 1]
  • POW: R = stack[SP]^(stack[SP - 1])
  • SQRT: R = stack[SP]^(-2)
• Logic
  • NOT: R = ~stack[SP]
  • OR: R = stack[SP] | stack[SP - 1]
  • AND: R = stack[SP] & stack[SP - 1]
  • MIR: R = reverse bits from stack[SP] (mirror)
• Stack manipulation:
  • PUSH value: stack[++SP] = value
  • PUSH $R: stack[++SP] = R
  • POP: stack[SP--] = 0
  • STORE: M = stack[SP]
  • LOAD: stack[++SP] = M
• IO:
  • OUT: print(stack[SP])
• Misc:
  • CLEAR: clears machine states
  • JMP instruction line: PC = instruction line
  • JZ instruction line: PC = instruction line if ZF
  • JN instruction line: PC = instruction line if NF

* instruction line could be different from line in file.

---

Program parser directives

define a constant

• constant_name EQU constant_value

define a label

• label_name:

* label can't be defined in the same line as a instruction.

See an example of loop using constant and label here.

---

Error codes

code	detail
0	Syntax error
1	Invalid instruction
2	Invalid argument
3	Stack already empty
4	Stack overflow
5	Could not read file
6	Unexpected runtime error
7	Division by zero not allowed
8	Number raised to negative number not allowed
9	Square root of negative numbers not allowed
10	Repeated label

---

Examples for validating the simulation:

• bhaskara.asm
• pitagoras.asm
• prime.asm
• root.asm
• fatorial.asm