Preevaluate cpustate

This emulates all the instructions in the basic block to get
the cpu state (regs, mem) at the end of the block.

Author: boriel

arch/zx48k/optimizer/__init__.py

@@ -208,6 +208,9 @@ def optimize(initial_memory):
     basic_blocks[0].prev = LABELS['*START*'].basic_block
     LABELS[END_PROGRAM_LABEL].basic_block.add_goes_to(LABELS['*__END_PROGRAM*'].basic_block)
 
+    for x in basic_blocks:
+        x.compute_cpu_state()
+
     for x in basic_blocks:
         x.optimize()
 

arch/zx48k/optimizer/basicblock.py

@@ -518,6 +518,16 @@ def guesses_initial_state_from_origin_blocks(self):
 
         return regs, mems
 
+    def compute_cpu_state(self):
+        """ Resets and updates internal cpu state of this block
+        executing the instructions of the block. The block must be a basic block
+        (i.e. already partitioned)
+        """
+        self.cpu.reset()
+
+        for asm_line in self.code:
+            self.cpu.execute(asm_line)
+
     def optimize(self):
         """ Tries to detect peep-hole patterns in this basic block
         and remove them.