diff --git a/README.md b/README.md
index e47bfcf..a8b2b83 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ or [riscemu.datenvorr.at](https://riscemu.datenvorr.at/index.html).
 This emulator contains:
 * RISC-V Assembly parser
 * RISC-V Assembly loader
-* Emulation for parts of the basic RISC-V instruction set
+* Emulation for most parts of the basic RISC-V instruction set and the M and A extensions
 * Naive memory emulator
 * Basic implementation of some syscalls 
 * A debugging environment
@@ -97,7 +97,6 @@ generate and make all doc files for you. Finally, you can open the docs locall b
   * RISC-V reference card: https://www.cl.cam.ac.uk/teaching/1617/ECAD+Arch/files/docs/RISCVGreenCardv8-20151013.pdf
   
 ## TODO:
- * Currently registers don't enforce 32 bit (no overflows etc)
  * Correctly handle 12 and 20 bit immediate (currently not limited to bits at all)
  * Add a cycle limit to the options and CPU to catch infinite loops
  * Move away from `print` and use `logging.logger` instead
diff --git a/riscemu/assembler.py b/riscemu/assembler.py
index 793484e..59165bf 100644
--- a/riscemu/assembler.py
+++ b/riscemu/assembler.py
@@ -84,7 +84,6 @@ class ParseContext:
         base = 0
         if self.section is not None:
             base = align_addr(self.section.current_address(), alignment)
-            print("base at {}".format(base))
         self._finalize_section()
         self.section = CurrentSection(name, type, base)
 
diff --git a/riscemu/syscall.py b/riscemu/syscall.py
index e46c49a..c7a1c3c 100644
--- a/riscemu/syscall.py
+++ b/riscemu/syscall.py
@@ -52,7 +52,7 @@ class Syscall:
         )
 
     def ret(self, code):
-        self.cpu.regs.set('a0', code)
+        self.cpu.regs.set('a0', Int32(code))
 
 
 def get_syscall_symbols():
@@ -91,9 +91,9 @@ class SyscallInterface:
         read syscall (63): read from file no a0, into addr a1, at most a2 bytes
         on return a0 will be the number of read bytes or -1 if an error occured
         """
-        fileno = scall.cpu.regs.get('a0')
-        addr = scall.cpu.regs.get('a1')
-        size = scall.cpu.regs.get('a2')
+        fileno = scall.cpu.regs.get('a0').unsigned_value
+        addr = scall.cpu.regs.get('a1').unsigned_value
+        size = scall.cpu.regs.get('a2').unsigned_value
         if fileno not in self.open_files:
             scall.cpu.regs.set('a0', -1)
             return
@@ -113,9 +113,9 @@ class SyscallInterface:
         write syscall (64): write a2 bytes from addr a1 into fileno a0
         on return a0 will hold the number of bytes written or -1 if an error occured
         """
-        fileno = scall.cpu.regs.get('a0')
-        addr = scall.cpu.regs.get('a1')
-        size = scall.cpu.regs.get('a2')
+        fileno = scall.cpu.regs.get('a0').unsigned_value
+        addr = scall.cpu.regs.get('a1').unsigned_value
+        size = scall.cpu.regs.get('a2').unsigned_value
         if fileno not in self.open_files:
             return scall.ret(-1)
 
@@ -147,9 +147,9 @@ class SyscallInterface:
             print(FMT_SYSCALL + '[Syscall] open: opening files not supported without scall-fs flag!' + FMT_NONE)
             return scall.ret(-1)
 
-        mode = scall.cpu.regs.get('a0')
-        addr = scall.cpu.regs.get('a1')
-        size = scall.cpu.regs.get('a2')
+        mode = scall.cpu.regs.get('a0').unsigned_value
+        addr = scall.cpu.regs.get('a1').unsigned_value
+        size = scall.cpu.regs.get('a2').unsigned_value
 
         mode_st = OPEN_MODES.get(mode, )
         if mode_st == -1:
@@ -176,7 +176,7 @@ class SyscallInterface:
 
         return -1 if an error was encountered, otherwise returns 0
         """
-        fileno = scall.cpu.regs.get('a0')
+        fileno = scall.cpu.regs.get('a0').unsigned_value
         if fileno not in self.open_files:
             print(FMT_SYSCALL + '[Syscall] close: unknown fileno {}!'.format(fileno) + FMT_NONE)
             return scall.ret(-1)
@@ -191,7 +191,7 @@ class SyscallInterface:
         Exit syscall. Exits the system with status code a0
         """
         scall.cpu.halted = True
-        scall.cpu.exit_code = scall.cpu.regs.get('a0')
+        scall.cpu.exit_code = scall.cpu.regs.get('a0').value
 
     def __repr__(self):
         return "{}(\n\tfiles={}\n)".format(