diff --git a/src/assembler.h b/src/assembler.h
index fa2e9be88c..a36e98d350 100644
--- a/src/assembler.h
+++ b/src/assembler.h
@@ -266,6 +266,7 @@ class Assembler {
 
     virtual bool reserved(int register_) = 0;
 
+    virtual unsigned argumentFootprint(unsigned footprint) = 0;
     virtual unsigned argumentRegisterCount() = 0;
     virtual int argumentRegister(unsigned index) = 0;
 
diff --git a/src/compile.cpp b/src/compile.cpp
index 8a7d61518b..4ed92f0432 100644
--- a/src/compile.cpp
+++ b/src/compile.cpp
@@ -345,8 +345,7 @@ alignedFrameSize(MyThread* t, object method)
     (localSize(t, method)
      - methodParameterFootprint(t, method)
      + codeMaxStack(t, methodCode(t, method))
-     + MaxNativeCallFootprint
-     - min(MaxNativeCallFootprint, t->arch->argumentRegisterCount()));
+     + t->arch->argumentFootprint(MaxNativeCallFootprint));
 }
 
 unsigned
diff --git a/src/compiler.cpp b/src/compiler.cpp
index 61cfa0097d..08f65d4904 100644
--- a/src/compiler.cpp
+++ b/src/compiler.cpp
@@ -635,20 +635,25 @@ class Event {
   unsigned readCount;
 };
 
+unsigned
+usableFrameSize(Context* c)
+{
+  return c->alignedFrameSize - c->arch->frameFooterSize();
+}
+
 int
 frameIndex(Context* c, int index)
 {
   assert(c, static_cast<int>
-         (c->alignedFrameSize + c->parameterFootprint - index - 1)
-         >= 0);
+         (usableFrameSize(c) + c->parameterFootprint - index - 1) >= 0);
 
-  return c->alignedFrameSize + c->parameterFootprint - index - 1;
+  return usableFrameSize(c) + c->parameterFootprint - index - 1;
 }
 
 unsigned
 frameIndexToOffset(Context* c, unsigned frameIndex)
 {
-  return ((frameIndex >= c->alignedFrameSize) ?
+  return ((frameIndex >= usableFrameSize(c)) ?
           (frameIndex
            + (c->arch->frameFooterSize() * 2)
            + c->arch->frameHeaderSize()) :
@@ -662,7 +667,7 @@ offsetToFrameIndex(Context* c, unsigned offset)
   unsigned normalizedOffset = offset / BytesPerWord;
 
   return ((normalizedOffset
-           >= c->alignedFrameSize
+           >= usableFrameSize(c)
            + c->arch->frameFooterSize()) ?
           (normalizedOffset
            - (c->arch->frameFooterSize() * 2)
@@ -2187,7 +2192,7 @@ saveLocals(Context* c, Event* e)
       if (DebugReads) {
         fprintf(stderr, "local save read %p at %d of %d\n",
                 local->value, ::frameIndex(c, li),
-                c->alignedFrameSize + c->parameterFootprint);
+                usableFrameSize(c) + c->parameterFootprint);
       }
 
       addRead(c, e, local->value, read
@@ -2272,7 +2277,7 @@ class CallEvent: public Event {
           if (DebugReads) {
             fprintf(stderr, "stack arg read %p at %d of %d\n",
                     s->value, frameIndex,
-                    c->alignedFrameSize + c->parameterFootprint);
+                    usableFrameSize(c) + c->parameterFootprint);
           }
 
           addRead(c, this, s->value, read
@@ -2284,7 +2289,7 @@ class CallEvent: public Event {
           if (DebugReads) {
             fprintf(stderr, "stack save read %p at %d of %d\n",
                     s->value, logicalIndex,
-                    c->alignedFrameSize + c->parameterFootprint);
+                    usableFrameSize(c) + c->parameterFootprint);
           }
 
           addRead(c, this, s->value, read
@@ -2307,7 +2312,7 @@ class CallEvent: public Event {
     }
 
     popIndex
-      = c->alignedFrameSize
+      = usableFrameSize(c)
       + c->parameterFootprint
       - (stackBefore ? stackBefore->index + 1 - stackArgumentFootprint : 0)
       - c->localFootprint;
@@ -4540,7 +4545,7 @@ class MyCompiler: public Compiler {
     c.localFootprint = localFootprint;
     c.alignedFrameSize = alignedFrameSize;
 
-    unsigned frameResourceCount = alignedFrameSize + parameterFootprint;
+    unsigned frameResourceCount = usableFrameSize(&c) + parameterFootprint;
 
     c.frameResources = static_cast<FrameResource*>
       (c.zone->allocate(sizeof(FrameResource) * frameResourceCount));
diff --git a/src/powerpc.cpp b/src/powerpc.cpp
index 18929f75e3..8b50add60b 100644
--- a/src/powerpc.cpp
+++ b/src/powerpc.cpp
@@ -651,6 +651,8 @@ void remainderR(Context* con, unsigned size, Reg* a, Reg* b, Reg* t) {
 void andC(Context* c, unsigned size, Assembler::Constant* a,
           Assembler::Register* b, Assembler::Register* dst)
 {
+  abort(c); // todo
+
   int64_t v = a->value->value();
 
   if(size == 8) {
@@ -667,7 +669,7 @@ void andC(Context* c, unsigned size, Assembler::Constant* a,
     andC(c, 4, &ah, &bh, &dh);
   } else {
     issue(c, andi(dst->low, b->low, v));
-    if (not isInt16(v)) {
+    if (v >> 16) {
       issue(c, andis(dst->low, b->low, v >> 16));
     }
   }
@@ -1209,6 +1211,10 @@ class MyArchitecture: public Assembler::Architecture {
     }
   }
 
+  virtual unsigned argumentFootprint(unsigned footprint) {
+    return footprint;
+  }
+
   virtual unsigned argumentRegisterCount() {
     return 8;
   }
@@ -1266,7 +1272,7 @@ class MyArchitecture: public Assembler::Architecture {
    unsigned, uint8_t* aTypeMask, uint64_t* aRegisterMask,
    bool* thunk)
   {
-    *aTypeMask = (1 << RegisterOperand);
+    *aTypeMask = (1 << RegisterOperand) | (1 << ConstantOperand);
     *aRegisterMask = ~static_cast<uint64_t>(0);
     *thunk = false;
   }
diff --git a/src/x86.cpp b/src/x86.cpp
index 83167927ce..1a867ef706 100644
--- a/src/x86.cpp
+++ b/src/x86.cpp
@@ -2021,6 +2021,11 @@ class MyArchitecture: public Assembler::Architecture {
     }
   }
 
+  virtual unsigned argumentFootprint(unsigned footprint) {
+    return footprint > argumentRegisterCount() ?
+      footprint - argumentRegisterCount() : 0;
+  }
+
   virtual unsigned argumentRegisterCount() {
     return (BytesPerWord == 4 ? 0 : 6);
   }