Add basic assembler w/o support for labels

Author: suyashmahar

tools/assembler.py

@@ -0,0 +1,105 @@
+import re
+import sys
+
+""" Define enum """
+def enum(**enums):
+    return type('Enum', (), enums)
+
+# Defines error_codes
+Errors = enum(ILLOP = 0, ILLREG=1)
+
+""" Compiles op codes into single dimensional array """
+def compile_opcodes():
+    # Define opcodes
+    opcodes = \
+    """.       .       .       .       .       .       .       .
+    .       .       .       .       .       .       .       .
+    .       .       .       .       .       .       .       .
+    LD      ST      .       JMP     .       BEQ     BNE     LDR
+    ADD     SUB     MUL     DIV     CMPEQ   CMPLT   CMPL    .
+    AND     OR      XOR     .       SHL     SHR     SRA     .
+    ADDC    SUBC    MULC    DIVC    CMPEQC  CMPLTC  CMPLEC  .
+    ANDC    ORC     XORC    .       SHLC    SHRC    SRAC    .
+    """
+
+    rr = re.compile(r"[^\s]+", re.VERBOSE)
+
+    # Read opcodes to single dimensional array
+    return rr.findall(opcodes)
+
+"""
+    Removes all comments from program
+"""
+def strip_comments(prog_content):
+    # temp = re.sub(r'[\n]+', '', prog_content)
+    return re.sub(r';.*', '', prog_content)
+
+""" Returns address for label """
+def get_literal(label):
+    return '000000000000000'
+
+"""
+    Converts one instruction into corresponding 
+    machine language instruction
+"""
+def convert_inst(instr, opcodes):
+    keyword_arr = re.split(r', |,| ', instr)
+    result ='{0:06b}'.format(opcodes.index(keyword_arr[0].upper()))
+
+    reg_used = instr.count('%')   
+    
+    if (len(keyword_arr) == 3): # JMP / LDR
+        if (reg_used == 2):
+            result += '{0:05b}'.format((keyword_arr[2])[2:]) # Rc
+            result += '{0:05b}'.format((keyword_arr[1])[2:]) # Ra
+            result += '0000000000000000'
+        else:
+            result += '{0:05b}'.format((keyword_arr[2])[2:]) # Rc
+            result += '11111'
+            result += get_literal(keyword_arr[1])
+    elif (len(keyword_arr) == 4):
+        if (reg_used == 2): # R1 literal R2
+            if (keyword_arr[0] == 'ST'): #ST
+                result += '{0:05b}'.format(int((keyword_arr[1])[2:])) # Rc
+                result += '{0:05b}'.format(int((keyword_arr[3])[2:])) # Ra
+                result += '{0:016b}'.format(int(keyword_arr[2])) # literal
+            elif (keyword_arr[0] == 'BEQ' | keyword_arr[0] == 'BNE'):
+                result += '{0:05b}'.format(int((keyword_arr[1])[2:])) # Rc
+                result += '{0:05b}'.format(int((keyword_arr[3])[2:])) # Ra
+                result += get_literal(keyword_arr[2]) # literal
+            else:
+                result += '{0:05b}'.format(int((keyword_arr[3])[2:])) # Rc
+                result += '{0:05b}'.format(int((keyword_arr[1])[2:])) # Ra
+                result += '{0:016b}'.format(int(keyword_arr[2])) # literal
+        else:
+            result += '{0:05b}'.format(int((keyword_arr[3])[2:])) # Rc
+            result += '{0:05b}'.format(int((keyword_arr[1])[2:])) # Ra
+            result += '{0:05b}'.format(int((keyword_arr[2])[2:])) # Ra
+            result += '00000000000'
+    return result
+"""
+    Error handling
+"""
+def handle_error(error_code, instruction):
+    if (error_code == Errors.ILLOP):
+        print "Illegal op code : " + str(instruction)
+    elif (error_code == Errors.ILLREG):
+        print "Illegal reg index : " + str(instruction)
+    exit()
+
+"""
+    Entry point of script
+"""
+def main(file_name):
+    # Load content of file and strip all comments
+    program_content = open(file_name, 'r').read()
+    program_content = strip_comments(program_content)
+    # Compile opcodes to single dimension array
+    opcodes = compile_opcodes()
+
+    for instr in re.split(r'\n', program_content):
+        print convert_inst(instr, opcodes)
+
+# Start here
+for arg in sys.argv[1:]:
+    main(arg)

tools/disassembler.py

@@ -54,8 +54,7 @@ def get_opcode_from_bin(opcode_bin):
     else:
         if (isWithLiteral):
             literal = line[-16:]
-            print opcode + "(R" + str(int(ra, 2)) + ", " + str(int(literal, 2)) + ", R" + str(int(rc, 2)) + ")"
+            print opcode + " %R" + str(int(ra, 2)) + ", " + str(int(literal, 2)) + ", %R" + str(int(rc, 2)) + ""
         else:
             rb = line[17:22]
-            print opcode + "(R" + str(int(ra, 2)) + ", R" + str(int(rb, 2)) + ", R" + str(int(rc, 2)) + ")"
-        
+            print opcode + " %R" + str(int(ra, 2)) + ", %R" + str(int(rb, 2)) + ", %R" + str(int(rc, 2)) + ""