xcomp: simplify further

dictionary.txt

@@ -98,6 +98,8 @@ J           -- n            Copy RS third item to PS
 C@          a -- c          Set c to byte at address a
 C!          c a --          Store byte c in address a
 CURRENT     -- a            Set a to wordref of last added entry.
+CURRENT*    -- a            A pointer to active CURRENT*. Useful when we have
+                            multiple active dicts.
 HERE        -- a            Push HERE's address
 H@          -- a            HERE @
 MOVE        a1 a2 u --      Copy u bytes from a1 to a2, starting with a1, going

emul/forth/xcomp.fs

@@ -4,3 +4,8 @@
 
 CURRENT @ XCURRENT !
 H@ ' _bend - 4 + XOFF !
+
+( dummy entry for dict hook )
+(xentry) _
+H@ 256 /MOD 2 PC! 2 PC!
+

forth/icore.fs

@@ -35,7 +35,8 @@
 : FLAGS 0x08 RAM+ ;
 : (parse*) 0x0a RAM+ ;
 : HERE 0x04 RAM+ ;
-: CURRENT 0x02 RAM+ ;
+: CURRENT* 0x51 RAM+ ;
+: CURRENT CURRENT* @ ;
 
 ( w -- a f )
 : (find) CURRENT @ SWAP _find ;
@@ -185,6 +186,7 @@
 ;
 
 : BOOT
+    0x02 RAM+ CURRENT* !
     LIT< (parse) (find) DROP (parse*) !
     ( 60 == SYSTEM SCRATCHPAD )
     CURRENT @ 0x60 RAM+ !

forth/xcomp.fs

@@ -14,7 +14,7 @@
   "'" and friends will *not* find words you're about to
   define. Only (xfind) will.
 
-  Words ":", "IMMEDIATE" and ":" are not automatically
+  Words ":", "IMMEDIATE" and "CODE" are not automatically
   shadowed to allow the harmless inclusion of this unit. This
   shadowing has to take place in your xcomp configuration.
 
@@ -24,67 +24,48 @@
 VARIABLE XCURRENT
 VARIABLE XOFF
 
-: (xentry)
-    H@           ( h )
-    WORD         ( h s )
-    SCPY         ( h )
-    ( Adjust HERE -1 because SCPY copies the null )
-    H@ 1 -       ( h h' )
-    DUP HERE !   ( h h' )
-    -^           ( sz )
-    ( write prev value )
-    H@ XCURRENT @ - ,
-    ( write size )
-    C,
-    H@ XCURRENT !
-;
+: XCON XCURRENT CURRENT* ! ;
+: XCOFF CURRENT CURRENT* ! ;
 
-( Finds in *both* CURRENT and XCURRENT )
-( w -- a f xa xf )
-: (xfind)
-    DUP                     ( w w )
-    CURRENT @ SWAP          ( w cur w )
-    _find                   ( w a f )
-    ROT                     ( a f w )
-    XCURRENT @ SWAP         ( a f xcur w )
-    _find                   ( a f xa xf )
-;
+: (xentry) XCON (entry) XCOFF ;
 
-: XCODE
-    (xentry) 23 ,
-;
+: XCODE XCON CODE XCOFF ;
 
-: XIMM
-    XCURRENT @ 1 -
-    DUP C@ 128 OR SWAP C!
-;
+: XIMM XCON IMMEDIATE XCOFF ;
 
 : X:
-    (xentry)
+    XCON
+    (entry)
     ( 0e == compiledWord )
     [ 0x0e LITN ] ,
     BEGIN
-    WORD
-    (xfind)
-    IF  ( a f xa )
+    ( DUP is because we need a copy in case it's IMMED )
+    WORD DUP
+    (find)      ( w a f )
+    IF
         ( is word )
         DUP IMMED?
-        IF  ( a f xa )
+        IF  ( w a )
             ( When encountering IMMEDIATE, we exec the *host*
               word. )
-            DROP    ( a f )
+            DROP    ( w )
+            ( hardcoded system CURRENT )
+            0x02 RAM+ @ SWAP        ( cur w )
+            _find                   ( a f )
             NOT IF ABORT THEN   ( a )
             EXECUTE
         ELSE
-            ( when compiling, we don't care about the host
-              find. )
+            ( not an immed. drop backup w and write, with
+              offset. )
+            SWAP DROP   ( a )
             DUP 0x100 > IF XOFF @ - THEN
-            , 2DROP
+            ,
         THEN
-    ELSE ( w f xa )
+    ELSE ( w a )
         ( maybe number )
-        2DROP   ( w )
+        DROP   ( w )
         (parse*) @ EXECUTE LITN
     THEN
     AGAIN
+    XCOFF
 ;

forth/z80c.fs

@@ -22,10 +22,6 @@
   This unit expects the same conf as boot.fs.
 )
 
-( dummy entry for dict hook )
-(xentry) _
-H@ 256 /MOD 2 PC! 2 PC!
-
 ( a b c -- b c a )
 CODE ROT
     HL POPqq,       ( C )

notes.txt

@@ -88,7 +88,8 @@ RAMSTART   INITIAL_SP
 +0e        WORDBUF
 +2e        SYSVNXT
 +4e        INTJUMP
-+51        RESERVED
++51        CURRENTPTR
++53        RESERVED
 +60        SYSTEM SCRATCHPAD
 +80        RAMEND
 
@@ -116,6 +117,11 @@ those slots...) in boot binaries are made to jump to this address. If you use
 one of those slots for an interrupt, write a jump to the appropriate offset in
 that RAM location.
 
+CURRENTPTR points to current CURRENT. The Forth CURRENT word doesn't return
+RAM+2 directly, but rather the value at this address. Most of the time, it
+points to RAM+2, but sometimes, when maintaining alternative dicts (during
+cross compilation for example), it can point elsewhere.
+
 SYSTEM SCRATCHPAD is reserved for temporary system storage or can be reserved
 by low-level drivers. These are the current usages of this space throughout the
 project: