fixed read syscall shadowing of len

riscemu/CPU.py

@@ -83,6 +83,7 @@ class CPU:
                 launch_debug_session(self, self.mmu, self.regs,
                                      "Exception encountered, launching debug:".format(self.pc-1))
 
+        print()
         print(FMT_CPU + "Program exited with code {}".format(self.exit_code) + FMT_NONE)
 
     def __run_instruction(self, ins: 'LoadedInstruction'):

riscemu/Syscall.py

@@ -70,12 +70,12 @@ class SyscallInterface:
         """
         fileno = scall.registers.get('a0')
         addr = scall.registers.get('a1')
-        len = scall.registers.get('a2')
+        size = scall.registers.get('a2')
         if fileno not in self.open_files:
             scall.registers.set('a0', -1)
             return
 
-        chars = self.open_files[fileno].read(len)
+        chars = self.open_files[fileno].read(size)
         try:
             data = bytearray(chars, 'ascii')
             scall.cpu.mmu.write(addr, len(data), data)