Sprint Pull: A Work in Progress

ls8/cpu.py

@@ -1,44 +1,81 @@
 """CPU functionality."""
-
+#
 import sys
 
+#instruction set:
+HLT = 0b00000001
+LDI = 0b10000010
+PRN = 0b01000111
+MUL = 0b10100010
+PUSH = 0b01000101
+POP = 0b01000110
+CALL = 0b01010000
+RET = 0b00010001
+CMP = 0b10100111
+JMP = 0b01010100
+JEQ = 0b01010101 
+JNE = 0b01010110
+
+# flags
+L = 0b100
+G = 0b10
+E = 0b1 
+
 class CPU:
     """Main CPU class."""
 
     def __init__(self):
-        """Construct a new CPU."""
-        pass
+        self.reg = [0] * 8
+        self.ram = [0] * 256
+        self.pc = 0
+        self.sp = 0 #set it to the first one in the stack?
+        self.fl = 0
 
-    def load(self):
-        """Load a program into memory."""
+        self.reg[self.sp] = 0xf4
 
-        address = 0
+#originally this part is `hardcoded` and needs the parser instead
+
+    def load(self, filename):
+        """Load a program into memory."""
+        try:
+            address = 0 #constant ram address
+            with open(filename) as f:
+                for line in f:
+                    comment_split = line.split("#")
+                    num = comment_split[0].strip()
+                    if num == '':
+                        continue
 
-        # For now, we've just hardcoded a program:
+                    self.ram[address] = int(num, 2)
+                    address += 1
 
-        program = [
-            # From print8.ls8
-            0b10000010, # LDI R0,8
-            0b00000000,
-            0b00001000,
-            0b01000111, # PRN R0
-            0b00000000,
-            0b00000001, # HLT
-        ]
+        except FileNotFoundError:
+            print("file not found")
+            sys.exit(2)
 
-        for instruction in program:
-            self.ram[address] = instruction
-            address += 1
+
+    def ram_read(self, address):
+        return self.ram[address]
 
+    def ram_write(self, newvalue, address):
+        self.ram[address] = newvalue
 
     def alu(self, op, reg_a, reg_b):
         """ALU operations."""
 
         if op == "ADD":
             self.reg[reg_a] += self.reg[reg_b]
-        #elif op == "SUB": etc
-        else:
-            raise Exception("Unsupported ALU operation")
+            self.pc += 3
+        elif op == "MUL":
+            self.reg[reg_a] *= self.reg[reg_b]
+            self.pc += 3
+            print()
+        elif op == "CMP":
+            if self.reg[reg_a] == self.reg[reg_b]:
+                self.fl = 1
+            else:
+                self.fl = 0
+            self.pc += 3
 
     def trace(self):
         """
@@ -61,5 +98,81 @@ def trace(self):
         print()
 
     def run(self):
-        """Run the CPU."""
-        pass
+        running = True
+        while running:
+            instruction = self.ram[self.pc]
+            operand_a = self.ram[self.pc + 1]
+            operand_b = self.ram[self.pc + 2]
+# LDI
+            if instruction == LDI:
+                reg_index = operand_a
+                num = operand_b
+                self.reg[reg_index] = num
+                self.pc += 3
+# PRN
+            elif instruction == PRN:
+                reg_index = operand_a
+                num = self.reg[reg_index]
+                print(num)
+                self.pc += 2
+#MUL
+            elif instruction == MUL:
+                self.alu("MUL", operand_a, operand_b)
+#PUSH       
+            elif instruction == PUSH:
+                reg_index = operand_a
+                val = self.reg[reg_index]
+
+                self.reg[self.sp] -= 1
+
+                self.ram[self.reg[self.sp]] = val
+                self.pc += 2
+#POP
+            elif instruction == POP:
+                reg_index = operand_a
+
+                self.reg[reg_index] = self.ram[self.reg[self.sp]]
+
+                self.reg[self.sp] += 1
+                self.pc += 2
+# HLT
+            elif instruction == HLT:
+                running = False
+                sys.exit(0)
+# CALL
+            elif instruction == CALL:
+                address_to_return_to = self.pc + 2
+                self.reg[self.pc] -= 1
+                self.ram[self.reg[self.sp]] = address_to_return_to
+                reg_index = operand_a
+                address_to_call = self.reg[reg_index]
+                self.pc = address_to_call
+# RET
+            elif instruction == RET:
+                self.pc = self.ram[self.reg[self.sp]]
+                self.reg[self.sp] + 1
+# CMP
+            elif instruction == CMP:
+                # if self.reg[self.ram_read(operand_a)] == self.reg[self.ram_read(operand_b)]:
+                #     self.reg[self.fl] = self.ref[self.fl] | (1<<0)
+                # else: self.reg[self.fl] 
+                self.alu("CMP", operand_a, operand_b)
+#JMP 
+            elif instruction == JMP:
+               self.pc = self.reg[operand_a]
+#JEP 
+            elif instruction == JEQ:
+                if self.fl & E:
+                    self.pc = self.reg[operand_a]
+                else:
+                    self.pc += 2
+#JNE 
+            elif instruction == JNE:
+                if not self.fl & E:
+                    self.pc = self.reg[operand_a]
+                else:
+                    self.pc += 2 
+
+            else:
+                print("WRONG WAY")
+                sys.exit(1)

ls8/ls8.py

@@ -5,7 +5,13 @@
 import sys
 from cpu import *
 
+if len(sys.argv) != 2:
+    print("Usage: python3 fileio.py <filename>")
+    sys.exit(1)
+
+filename = sys.argv[1]
+
 cpu = CPU()
 
-cpu.load()
+cpu.load(filename)
 cpu.run()