Data commit

Task/Compiler-virtual-machine-interpreter/Python/compiler-virtual-machine-interpreter.py

@@ -0,0 +1,168 @@
+from __future__ import print_function
+import sys, struct
+
+FETCH, STORE, PUSH, ADD, SUB, MUL, DIV, MOD, LT, GT, LE, GE, EQ, NE, AND, OR, NEG, NOT, \
+JMP, JZ, PRTC, PRTS, PRTI, HALT = range(24)
+
+code_map = {
+    "fetch": FETCH,
+    "store": STORE,
+    "push":  PUSH,
+    "add":   ADD,
+    "sub":   SUB,
+    "mul":   MUL,
+    "div":   DIV,
+    "mod":   MOD,
+    "lt":    LT,
+    "gt":    GT,
+    "le":    LE,
+    "ge":    GE,
+    "eq":    EQ,
+    "ne":    NE,
+    "and":   AND,
+    "or":    OR,
+    "not":   NOT,
+    "neg":   NEG,
+    "jmp":   JMP,
+    "jz":    JZ,
+    "prtc":  PRTC,
+    "prts":  PRTS,
+    "prti":  PRTI,
+    "halt":  HALT
+}
+
+input_file  = None
+code        = bytearray()
+string_pool = []
+word_size   = 4
+
+#*** show error and exit
+def error(msg):
+    print("%s" % (msg))
+    exit(1)
+
+def int_to_bytes(val):
+    return struct.pack("<i", val)
+
+def bytes_to_int(bstr):
+    return struct.unpack("<i", bstr)
+
+#***
+def emit_byte(x):
+    code.append(x)
+
+#***
+def emit_word(x):
+    s = int_to_bytes(x)
+    for x in s:
+        code.append(x)
+
+#***
+def run_vm(data_size):
+    stack = [0 for i in range(data_size + 1)]
+    pc = 0
+    while True:
+        op = code[pc]
+        pc += 1
+
+        if op == FETCH:
+            stack.append(stack[bytes_to_int(code[pc:pc+word_size])[0]]);
+            pc += word_size
+        elif op == STORE:
+            stack[bytes_to_int(code[pc:pc+word_size])[0]] = stack.pop();
+            pc += word_size
+        elif op == PUSH:
+            stack.append(bytes_to_int(code[pc:pc+word_size])[0]);
+            pc += word_size
+        elif op == ADD:   stack[-2] += stack[-1]; stack.pop()
+        elif op == SUB:   stack[-2] -= stack[-1]; stack.pop()
+        elif op == MUL:   stack[-2] *= stack[-1]; stack.pop()
+        # use C like division semantics
+        elif op == DIV:   stack[-2] = int(float(stack[-2]) / stack[-1]); stack.pop()
+        elif op == MOD:   stack[-2] = int(float(stack[-2]) % stack[-1]); stack.pop()
+        elif op == LT:    stack[-2] = stack[-2] <  stack[-1]; stack.pop()
+        elif op == GT:    stack[-2] = stack[-2] >  stack[-1]; stack.pop()
+        elif op == LE:    stack[-2] = stack[-2] <= stack[-1]; stack.pop()
+        elif op == GE:    stack[-2] = stack[-2] >= stack[-1]; stack.pop()
+        elif op == EQ:    stack[-2] = stack[-2] == stack[-1]; stack.pop()
+        elif op == NE:    stack[-2] = stack[-2] != stack[-1]; stack.pop()
+        elif op == AND:   stack[-2] = stack[-2] and stack[-1]; stack.pop()
+        elif op == OR:    stack[-2] = stack[-2] or  stack[-1]; stack.pop()
+        elif op == NEG:   stack[-1] = -stack[-1]
+        elif op == NOT:   stack[-1] = not stack[-1]
+        elif op == JMP:   pc += bytes_to_int(code[pc:pc+word_size])[0]
+        elif op == JZ:
+            if stack.pop():
+                pc += word_size
+            else:
+                pc += bytes_to_int(code[pc:pc+word_size])[0]
+        elif op == PRTC:  print("%c" % (stack[-1]), end=''); stack.pop()
+        elif op == PRTS:  print("%s" % (string_pool[stack[-1]]), end=''); stack.pop()
+        elif op == PRTI:  print("%d" % (stack[-1]), end=''); stack.pop()
+        elif op == HALT:  break
+
+def str_trans(srce):
+    dest = ""
+    i = 0
+    while i < len(srce):
+        if srce[i] == '\\' and i + 1 < len(srce):
+            if srce[i + 1] == 'n':
+                dest += '\n'
+                i += 2
+            elif srce[i + 1] == '\\':
+                dest += '\\'
+                i += 2
+        else:
+            dest += srce[i]
+            i += 1
+
+    return dest
+
+#***
+def load_code():
+    global string_pool
+
+    line = input_file.readline()
+    if len(line) == 0:
+        error("empty line")
+
+    line_list = line.split()
+    data_size = int(line_list[1])
+    n_strings = int(line_list[3])
+
+    for i in range(n_strings):
+        string_pool.append(str_trans(input_file.readline().strip('"\n')))
+
+    while True:
+        line = input_file.readline()
+        if len(line) == 0:
+            break
+        line_list = line.split()
+        offset = int(line_list[0])
+        instr  = line_list[1]
+        opcode = code_map.get(instr)
+        if opcode == None:
+            error("Unknown instruction %s at %d" % (instr, offset))
+        emit_byte(opcode)
+        if opcode in [JMP, JZ]:
+            p = int(line_list[3])
+            emit_word(p - (offset + 1))
+        elif opcode == PUSH:
+            value = int(line_list[2])
+            emit_word(value)
+        elif opcode in [FETCH, STORE]:
+            value = int(line_list[2].strip('[]'))
+            emit_word(value)
+
+    return data_size
+
+#*** main driver
+input_file = sys.stdin
+if len(sys.argv) > 1:
+    try:
+        input_file = open(sys.argv[1], "r", 4096)
+    except IOError as e:
+        error(0, 0, "Can't open %s" % sys.argv[1])
+
+data_size = load_code()
+run_vm(data_size)