forth: Forth-ify "I", "I'", "J"

forth/forth.asm

@@ -1313,39 +1313,9 @@ R2P:
 	push	hl
 	jp	next
 
-	.db	"I"
-	.dw	$-R2P
-	.db	1
-I:
-	.dw	nativeWord
-	ld	l, (ix)
-	ld	h, (ix+1)
-	push	hl
-	jp	next
-
-	.db	"I'"
-	.dw	$-I
-	.db	2
-IPRIME:
-	.dw	nativeWord
-	ld	l, (ix-2)
-	ld	h, (ix-1)
-	push	hl
-	jp	next
-
-	.db	"J"
-	.dw	$-IPRIME
-	.db	1
-J:
-	.dw	nativeWord
-	ld	l, (ix-4)
-	ld	h, (ix-3)
-	push	hl
-	jp	next
-
 ; ( a b -- c ) A + B
 	.db "+"
-	.dw $-J
+	.dw $-R2P
 	.db 1
 PLUS:
 	.dw nativeWord

forth/z80a.fs

@@ -26,6 +26,12 @@
   extra 0xdd / 0xfd and then spit the equivalent of HL )
 : IX 0xdd A, HL ;
 : IY 0xfd A, HL ;
+: _ix+- 0xff AND 0xdd A, (HL) ;
+: _iy+- 0xff AND 0xfd A, (HL) ;
+: IX+ _ix+- ;
+: IX- 0 -^ _ix+- ;
+: IY+ _iy+- ;
+: IY- 0 -^ _iy+- ;
 
 ( -- )
 : OP1 CREATE C, DOES> C@ A, ;
@@ -77,17 +83,35 @@
 0x03 OP1qq INCss,
 0x09 OP1qq ADDHLss,
 
-( rd rr )
+: _1rr
-: OP1rr
-    CREATE C,
-    DOES>
     C@              ( rd rr op )
     ROT             ( rr op rd )
     8 *             ( rr op rd<<3 )
     OR OR A,
 ;
+
+( rd rr )
+: OP1rr
+    CREATE C,
+    DOES>
+    _1rr
+;
 0x40 OP1rr LDrr,
 
+( ixy+- HL rd )
+: LDIXYr,
+    ( dd/fd has already been spit )
+    LDrr,           ( ixy+- )
+    A,
+;
+
+( rd ixy+- HL )
+: LDrIXY,
+    ROT             ( ixy+- HL rd )
+    SWAP            ( ixy+- rd HL )
+    LDIXYr,
+;
+
 ( n -- )
 : OP2n
     CREATE C,

forth/z80c.fs

@@ -168,3 +168,21 @@ CODE PC@
     L INr(C),
     HL PUSHqq,
 ;CODE
+
+CODE I
+    L 0 IX+ LDrIXY,
+    H 1 IX+ LDrIXY,
+    HL PUSHqq,
+;CODE
+
+CODE I'
+    L 2 IX- LDrIXY,
+    H 1 IX- LDrIXY,
+    HL PUSHqq,
+;CODE
+
+CODE J
+    L 4 IX- LDrIXY,
+    H 3 IX- LDrIXY,
+    HL PUSHqq,
+;CODE