Changed stack architecture to move downwards.

TikzPainter have been adjusted for the change.
Stack limits are now shown.

Emulator.py

@@ -8,11 +8,13 @@ REGISTERS=["%rax", "%rbx", "%rcx", "%rdx", "%rsp", "%rbp", "%rsi", "%rdi",
 
 class Emulator:
 
-	def __init__ (self, source_text):
+	def __init__ (self, source_text, max_stack_size=1000):
 		self.registers = {}
 		for reg_name in REGISTERS:
 			self.registers[reg_name] = "Junk"
 		self.stack = {}
+		for i in range(max_stack_size):
+			self.stack[i] = 0
 		self.code = []
 		self.labels = {}
 		self.changes = {}
@@ -28,12 +30,13 @@ class Emulator:
 		Sets various stack elements, starting from 0 and going up.
 		Automatically sets rsp. This can be disabled by passing set_rsp=False.
 		"""
-		i = -1
+		i = len(self.stack)
 		for element in stack_list:
-			i += 1
+			i -= 1
 			self.stack[i] = element
 		if (not 'set_rsp' in kwargs) or kwargs['set_rsp']:
 			self.setRegs(rsp=i)
+			self.last_sp = i-1
 
 	def setRegs (self, **reg_dict):
 		for reg_name, reg_val in reg_dict.iteritems():
@@ -82,15 +85,15 @@ class Emulator:
 		return [ "\\"+token if token[0]=="$" or token[0]=="%" else token for token in self.code[line_nr] ]
 
 	def pushToStack (self, new_element):
-		self.registers['%rsp'] = self.registers['%rsp'] + 1
+		self.registers['%rsp'] -= 1
 		self.stack[self.registers['%rsp']] = new_element
 		self.changedRegisters(('%rsp',"change"), ("m"+str(self.registers['%rsp']),"insert"))
 		self.max_stack_size = max(self.registers['%rsp'], self.max_stack_size)
 
 	def popFromStack (self):
 		temp = self.stack[self.registers['%rsp']]
-		self.registers['%rsp'] -= 1
-		self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']+1),"remove"))
+		self.changedRegisters(('%rsp',"change"),("m"+str(self.registers['%rsp']),"remove"))
+		self.registers['%rsp'] += 1
 		return temp
 
 	def iterate (self):

TikzPainter.py

@@ -9,11 +9,12 @@ REG_STATUS_TO_COLOR = {
 
 class TikzPainter:
 
-	def __init__ (self, registers=None, max_stack_size=8):
+	def __init__ (self, registers=None, max_stack_size=8, stack_draw_mode="up"):
 		self.registers = registers if registers else REGISTERS
 		self.text = []
 		self.pos_x = 0
 		self.max_stack_size = max_stack_size
+		self.stack_draw_mode = stack_draw_mode
 
 	def addText (self, str, *args):
 		self.text.append(str.format(*args))
@@ -21,6 +22,33 @@ class TikzPainter:
 	def getRegColor (self, reg_state):
 		return REG_STATUS_TO_COLOR[reg_state]
 
+	def drawStackUpward (self, pos, emu, x):
+		base_pointer = emu.getVal('%rbp')
+
+		pos -= 1.5
+		base_sp = min(emu.last_sp, emu.getVal('%rsp'))
+		pos += 0.5 * max(0, emu.getVal('%rsp')-emu.last_sp)
+		for index in range(base_sp, 3+min(emu.max_stack_size, emu.getVal('%rsp')+self.max_stack_size)):
+			reg_state = emu.regState("m"+str(index))
+			reg_dect = "register_node, fill="+self.getRegColor(reg_state)+"!10"
+			self.addText("\t\\node[{}]() at ({}, {}){{{}}};\n",
+					reg_dect, x, pos, emu.stack[index])
+			if base_pointer == index:
+				self.addText("\t\\draw ({0},{2}) -- ({1},{2});\n",x-1.1,x+1.1,pos-0.25)
+				base_pointer = emu.stack[base_pointer]
+			pos -= 0.5
+		return pos, x
+
+	def drawStackDownward (self, pos, emu, x):
+		pos -= 1
+		for index in range(emu.getVal('%rsp')-8, max(emu.last_sp, emu.getVal('%rsp'))):
+			reg_state = emu.regState("m"+str(index))
+			reg_dect = "register_node, fill="+self.getRegColor(reg_state)+"!10"
+			self.addText("\t\\node[{}]() at ({}, {}){{{}}};\n",
+					reg_dect, x, pos, emu.stack[index])
+			pos -= 0.5
+		return pos, x
+
 	def drawState (self, emu, line_nr=None):
 		x = (self.pos_x+1)*2.5-0.5
 		self.pos_x += 1
@@ -37,16 +65,10 @@ class TikzPainter:
 					reg_dect, x, pos, emu.getVal(reg_name))
 
 		# Draw stack
-		pos -= 1.5
-		base_sp = max(emu.last_sp, emu.getVal('%rsp'))
-		if emu.last_sp - 1 == emu.getVal('%rsp'):
-			pos += 0.5
-		for index in range(base_sp, max(-1, base_sp-self.max_stack_size),-1):
-			reg_state = emu.regState("m"+str(index))
-			reg_dect = "register_node, fill="+self.getRegColor(reg_state)+"!10"
-			self.addText("\t\\node[{}]() at ({}, {}){{{}}};\n",
-					reg_dect, x, pos, emu.stack[index])
-			pos -= 0.5
+		if self.stack_draw_mode == "up":
+			pos, x = self.drawStackUpward(pos, emu, x)
+		else:
+			pos, x = self.drawStackDownward(pos, emu, x)
 
 		# Draw line signature
 		if line_nr == None:
@@ -54,22 +76,34 @@ class TikzPainter:
 		pos = 2
 		signature = emu.getLineSignature(line_nr)
 		for token in signature:
-			self.addText("\t\\node[text_node]() at ({}, {}){{{}}};\n", x-1.25, pos, token)
+			self.addText("\t\\node[text_node]() at ({}, {}){{{}}};\n",
+						x-1.25, pos, token)
 			pos -= 0.5
 
 	def drawNames (self, emu):
 		x = 0
 		pos = 0
 		for reg_name in self.registers:
-			self.addText("\t\\node[text_node]() at ({}, {}){{{}}};\n", x, pos, reg_name[1:])
+			self.addText("\t\\node[text_node]() at ({}, {}){{{}}};\n",
+						x, pos, reg_name[1:])
 			pos -= 0.5
 
-		self.addText("\t\\node[text_node]() at ({}, {}){{TOS+1}};\n", x, pos-0.5)
-		self.addText("\t\\node[text_node]() at ({}, {}){{TOS}};\n", x, pos-1.0)
+		# Draw stack
+		if self.stack_draw_mode == "up":
+			self.drawStackNamesUpward(pos, emu, x)
+		else:
+			self.drawStackNamesDownward(pos, emu, x)
+
+	def drawStackNamesUpward (self, pos, emu, x):
+		self.addText("\t\\node[text_node]() at ({}, {}){{TOS+1}};\n",
+					x, pos-0.5)
+		self.addText("\t\\node[text_node]() at ({}, {}){{TOS}};\n",
+					x, pos-1.0)
 		pos -= 1
 		for index in range(1,self.max_stack_size):
 			pos -= 0.5
-			self.addText("\t\\node[text_node]() at ({}, {}){{TOS-{}}};\n", x, pos, index)
+			self.addText("\t\\node[text_node]() at ({}, {}){{TOS-{}}};\n",
+						x, pos, index)
 
 	def __str__ (self):
 		return "".join(self.text)

tests/test_fib.py

@@ -49,8 +49,8 @@ return:	leave           # Clean up
 
 
 OPTIONS = """register_node/.style={rectangle, draw=black!30,
-			 fill=black!5, very thick, minimum size=0.5, minimum width=20mm},
-			 text_node/.style={}"""
+			 fill=black!5, very thick, minimum size=0.5,
+			 minimum width=20mm}, text_node/.style={}"""
 
 def printf (str, *args):
 	print(str.format(*args))