forth: add a stable ABI

forth/dictionary.txt

@@ -55,7 +55,7 @@ LITN        n --            Write number n as a literal.
 [LITN]      n --            *I* Immediate version of LITN.
 ROUTINE x   -- a            Push the addr of the specified core routine
                             C=cellWord L=compiledWord V=nativeWord N=next S=LIT
-                            N=NUMBER Y=sysvarWord D=doesWord
+                            M=NUMBER Y=sysvarWord D=doesWord
 VARIABLE c  --              Creates cell x with 2 bytes allocation.
 
 Compilation vs meta-compilation. When you compile a word with "[COMPILE] foo",

forth/forth.asm

@@ -108,6 +108,14 @@
 ; At the end of every compiledWord is an EXIT. This pops RS, sets IP to it, and
 ; continues.
 
+; *** Stable ABI ***
+; Those jumps below are supposed to stay at these offsets, always. If they
+; change bootstrap binaries have to be adjusted because they rely on them.
+.fill 0x1a-$
+JUMPTBL:
+	jp	next
+	jp	chkPS
+
 ; *** Code ***
 forthMain:
 	; STACK OVERFLOW PROTECTION:
@@ -185,12 +193,6 @@ INTERPRET:
 	.db	30
 	; infinite loop
 
-; Oops, I forgot to create a stable ABI before starting to rely on stability...
-; I'll fix this soon, but for now, I need to offset a recent simplification
-; I've made in INTERPRET above. If we don't, z80c.bin doesn't refer to proper
-; routine addresses...
-.fill 14
-
 ; *** Collapse OS lib copy ***
 ; In the process of Forth-ifying Collapse OS, apps will be slowly rewritten to
 ; Forth and the concept of ASM libs will become obsolete. To facilitate this
@@ -815,7 +817,7 @@ ROUTINE:
 	ld	de, nativeWord
 	cp	'V'
 	jr	z, .end
-	ld	de, next
+	ld	de, JUMPTBL
 	cp	'N'
 	jr	z, .end
 	ld	de, sysvarWord
@@ -828,9 +830,9 @@ ROUTINE:
 	cp	'S'
 	jr	z, .end
 	ld	de, NUMBER
-	cp	'N'
+	cp	'M'
 	jr	z, .end
-	ld	de, chkPS
+	ld	de, JUMPTBL+3
 	cp	'P'
 	jr	nz, .notgood
 	; continue to end on match

forth/z80c.fs

@@ -34,7 +34,7 @@ CODE ROT
 CODE 2DUP
     HL POPqq,       ( B )
     DE POPqq,       ( A )
-    ROUTINE P CALLnn,
+    chkPS,
     DE PUSHqq,      ( A )
     HL PUSHqq,      ( B )
     DE PUSHqq,      ( A )
@@ -48,7 +48,7 @@ CODE 2OVER
     DE POPqq,       ( C )
     BC POPqq,       ( B )
     IY POPqq,       ( A )
-    ROUTINE P CALLnn,
+    chkPS,
     IY PUSHqq,      ( A )
     BC PUSHqq,      ( B )
     DE PUSHqq,      ( C )
@@ -64,7 +64,7 @@ CODE 2SWAP
     DE POPqq,       ( C )
     BC POPqq,       ( B )
     IY POPqq,       ( A )
-    ROUTINE P CALLnn,
+    chkPS,
     DE PUSHqq,      ( C )
     HL PUSHqq,      ( D )
     IY PUSHqq,      ( A )