emul: build boot binary in one pass

... instead of building boot.fs, and then z80c.fs/icore.fs in separate
passes. This strengten xcomp by making it support 2 completely separate
dicts (that is, the X dict is *not* connected to the system dict. The chain
now stops at EXIT def in boot.fs).

emul/Makefile

@@ -15,10 +15,10 @@ $(SLATEST):
 $(BIN2C):
 	$(MAKE) -C ../tools
 
-# z80c.bin and boot.bin are not in the prerequisites because they're bootstrap
-# binaries that should be updated manually through make updatebootstrap.
+# z80c.bin is not in the prerequisites because it's a bootstrap
+# binary that should be updated manually through make updatebootstrap.
 forth/forth0.bin: $(SLATEST)
-	cat forth/boot.bin forth/z80c.bin > $@
+	cp forth/z80c.bin $@
 	$(SLATEST) $@
 	cat forth/emul.fs >> $@
 
@@ -37,7 +37,7 @@ forth/core.bin: $(FORTHSRC_PATHS) forth/stage1
 	cat $(FORTHSRC_PATHS) ./forth/stop.fs | $(STRIPFC) | ./forth/stage1 | tee $@ > /dev/null
 
 forth/forth1.bin: forth/core.bin $(SLATEST)
-	cat forth/boot.bin forth/z80c.bin forth/core.bin > $@
+	cat forth/z80c.bin forth/core.bin > $@
 	$(SLATEST) $@
 
 forth/forth1-bin.h: forth/forth1.bin $(BIN2C)
@@ -60,10 +60,11 @@ emul.o: emul.c
 	$(CC) -c -o emul.o emul.c
 
 
+forth/z80c.bin: forth/stage2
+	cat ./forth/conf.fs ../forth/xcomp.fs ./forth/xcomp.fs ../forth/boot.fs ../forth/z80c.fs ../forth/icore.fs | ./forth/stage2 | tee $@ > /dev/null
+
 .PHONY: updatebootstrap
-updatebootstrap: forth/stage2
-	cat ./forth/conf.fs ../forth/boot.fs | ./forth/stage2 | tee forth/boot.bin > /dev/null
-	cat ./forth/conf.fs ../forth/xcomp.fs ./forth/xcomp.fs ../forth/z80c.fs ../forth/icore.fs | ./forth/stage2 | tee forth/z80c.bin > /dev/null
+updatebootstrap: forth/z80c.bin
 
 .PHONY: clean
 clean:

emul/forth/xcomp.fs

@@ -14,7 +14,5 @@
 
 CURRENT @ XCURRENT !
 
-( dummy entry for dict hook )
-(xentry) _
 H@ 256 /MOD 2 PC! 2 PC!
-H@ ' _bend - XOFF !
+H@ XOFF !

forth/boot.fs

@@ -381,5 +381,4 @@ NOP, NOP, NOP, NOP, NOP,
 '_' A, 'b' A, 'e' A, 'n' A, 'd' A,
 PC L2 @ - A,, ( prev )
 5 A,
-
-H@ 256 /MOD 2 PC! 2 PC!
+H@ XCURRENT !        ( set current tip of dict )

forth/xcomp.fs

@@ -95,9 +95,20 @@ VARIABLE XOFF
             ,
         THEN
     ELSE ( w a )
-        ( maybe number )
+        ( not found? it might be an immediate that isn't yet defined in our
+          cross-compiled dict. It's alright, we can find-and-execute it. )
         DROP ( w )
+        ( system CURRENT )
+        0x02 RAM+ @ SWAP        ( cur w )
+        _find                   ( a f )
+        IF
+            ( found. It *must* be an IMMED )
+            DUP IMMED? NOT IF ABORT THEN
+            EXECUTE
+        ELSE
+            ( not found. maybe number )
             (parse*) @ EXECUTE LITN
         THEN
+    THEN
     AGAIN
 ;