avra: begin implementing forward label system

blk/660

@@ -1 +1 @@
-1 8 LOADR+
+1 9 LOADR+

blk/661

@@ -1,4 +1,5 @@
 VARIABLE ORG
+VARIABLE L1 VARIABLE L2 VARIABLE L3 VARIABLE L4
 : SPLITB
     256 /MOD SWAP
 ;

blk/668

@@ -2,7 +2,7 @@
 : _r7ffc DUP 0x7ff > IF _oor THEN ;
 : _raddr12
     PC - DUP 0< IF 0x800 + _r7ffc 0x800 OR ELSE _r7ffc THEN ;
-: RJMP ( a -- op ) _raddr12 0xc000 OR ;
-: RCALL ( a -- op ) _raddr12 0xd000 OR ;
-: RJMP, RJMP A,, ;
-: RCALL, RCALL A,, ;
+0xc0 CONSTANT RJMPOP
+0xd0 CONSTANT RCALLOP
+: RJMP, _raddr12 RJMPOP 8 LSHIFT OR A,, ;
+: RCALL, _raddr12 RCALLOP 8 LSHIFT OR A,, ;

blk/669

@@ -0,0 +1,10 @@
+( ex: L1 LBL! .. L1 @ RJMP, )
+: LBL! ( l -- ) PC SWAP ! ;
+( ex: L1 FLBL, .. RJMPOP L1 FLBL! )
+: FLBL, ( l -- ) LBL! 0 A,, ;
+: FLBL! ( op l -- )
+    @ DUP PC -^ 1-  ( op l off )
+    ROT 8 LSHIFT OR ( l op' )
+    ( warning: l is a PC offset, not a mem addr! )
+    SWAP 2 * ORG @ + ( op' addr ) ! ;
+