Make string length-prefixed instead of null-terminated

I'm not sure why I chose null-terminated initially. Probably because
the z80asm version had null-terminated strings.

Length-prefixes strings are the traditional form of strings in Forth
and it's a bit easier to work with them with traditional forth words
when they're under this form.

blk/288

@@ -3,14 +3,8 @@ PC ORG @ 0x22 + ! ( litWord, 0xf7, tight on the 0x100 limit )
   number, it's followed by a null-terminated string. When
   called, puts the string's address on PS )
     IY PUSHqq, HL POPqq, ( <-- IP )
+    E (HL) LDrr, D 0 LDrn,
+    DE INCss,
+    DE ADDIYss,
     HL PUSHqq,
-    ( skip to null char )
-    A XORr, ( look for null )
-    B A LDrr,
-    C A LDrr,
-    CPIR,
-	( CPIR advances HL regardless of comparison, so goes one
-      char after NULL. This is good, because that's what we
-      want... )
-    HL PUSHqq, IY POPqq, ( --> IP )
     JPNEXT,

blk/289

@@ -1,5 +1,5 @@
 ( Name of BOOT word )
-L1 BSET 'B' A, 'O' A, 'O' A, 'T' A, 0 A,
+L1 BSET 4 A, 'B' A, 'O' A, 'O' A, 'T' A,
 
 PC ORG @ 1 + ! ( main )
 ( STACK OVERFLOW PROTECTION: See B76 )

blk/291

@@ -5,12 +5,12 @@ PC ORG @ 4 + ! ( find )
     BC PUSHqq,
     HL PUSHqq,
 	( First, figure out string len )
-    BC 0 LDddnn,
-    A XORr,
-    CPIR,
-	( C has our length, negative, -1 )
-    A C LDrr,
-    NEG,
-    A DECr,
+    A (HL) LDrr, A ORr,
 	( special case. zero len? we never find anything. )
-    IFNZ, ( fail-B296 )                               ( cont. )
+    IFNZ, ( fail-B296 )
+( Let's do something weird: We'll hold HL by the *tail*.
+  Because of our dict structure and because we know our
+  lengths, it's easier to compare starting from the end. )
+    C A LDrr, B 0 LDrn, ( C holds our length )
+    BC ADDHLss, HL INCss, ( HL points to after-last-char )
+                                                     ( cont . )

blk/292

@@ -1,11 +1,3 @@
-    C A LDrr, ( C holds our length )
-( Let's do something weird: We'll hold HL by the *tail*.
-  Because of our dict structure and because we know our
-  lengths, it's easier to compare starting from the end.
-  Currently, after CPIR, HL points to char after null. Let's
-  adjust. Because the compare loop pre-decrements, instead
-  of DECing HL twice, we DEC it once. )
-    HL DECss,
     BEGIN, ( inner )
     ( DE is a wordref, first step, do our len correspond? )
         HL PUSHqq,          ( --> lvl 1 )

blk/298

@@ -1,4 +1,4 @@
-'(' A, 'u' A, 'f' A, 'l' A, 'w' A, ')' A, 0 A,
+6 A, '(' A, 'u' A, 'f' A, 'l' A, 'w' A, ')' A,
 L2 BSET ( abortUnderflow )
     HL PC 7 - LDddnn,
     DE RAMSTART 0x02 + LDdd(nn),   ( RAM+02 == CURRENT )

blk/328

@@ -1,14 +1,15 @@
 CODE S=
-    DE  POPqq,
-    HL  POPqq,
-    chkPS,
-    BEGIN,
-        LDA(DE),
-        (HL) CPr,
-        JRNZ, BREAK, ( not equal? break early. NZ is set. )
-        A ORr,   ( if our char is null, stop )
-        HL INCss,
-        DE INCss,
-    JRNZ, AGAIN,
+    DE POPqq, HL POPqq, chkPS,
+    LDA(DE),
+    (HL) CPr,
+    IFZ, ( same size? )
+        B A LDrr, ( loop A times )
+        BEGIN,
+            HL INCss, DE INCss,
+            LDA(DE),
+            (HL) CPr,
+            JRNZ, BREAK, ( not equal? break early. NZ is set. )
+        DJNZ, AGAIN,
+    THEN,
     PUSHZ,
 ;CODE

blk/354

@@ -11,3 +11,4 @@
 : C!+ ( c a -- a+1 ) TUCK C! 1+ ;
 : C@- ( a -- a-1 c ) DUP C@ SWAP 1- SWAP ;
 : C!- ( c a -- a-1 ) TUCK C! 1- ;
+: LEAVE R> R> DROP I 1- >R >R ; : UNLOOP R> 2R> 2DROP >R ;

blk/357

@@ -1,16 +1,11 @@
-: (parsed)      ( a -- n f )
-    DUP C@                        ( a c )
-    DUP '-' = IF
-        DROP 1+ ( a+1 ) (parsed) 0 ROT ( f 0 n )
+: _ ( a+1 len -- n f )
+    OVER C@ ( a len c )
+    '-' = IF
+        1- SWAP 1+ SWAP ( a+1 len-1 ) _ 0 ROT ( f 0 n )
         - SWAP EXIT                    ( 0-n f )
-    THEN
-    0 SWAP _pdacc                 ( a r f )
-    ?DUP IF 2DROP 0 EXIT THEN
-    BEGIN                         ( a r )
-        SWAP 1+                   ( r a+1 )
-        DUP C@                    ( r a c )
-        ROT SWAP                  ( a r c )
-        _pdacc                    ( a r f )
-    ?DUP UNTIL
-    1 =         ( a r f )
-    ROT DROP    ( r f ) ;
+    THEN ( a len )
+    0 SWAP ( len ) 0 DO ( a r )
+        OVER I + C@ ( a r c ) _pdacc ( a r f )
+        IF DROP 1- 0 UNLOOP EXIT THEN LOOP ( a r )
+    NIP 1 ;
+: (parsed) ( a -- n f ) C@+ ( a+1 l ) _ ;

blk/358

@@ -3,9 +3,9 @@
 
 : (parsec)          ( a -- n f )
     ( apostrophe is ASCII 39 )
-    DUP C@ 39 = OVER 2+ C@ 39 = AND     ( a f )
+    DUP 1+ C@ 39 = OVER 3 + C@ 39 = AND  ( a f )
     NOT IF 0 EXIT THEN   ( a 0 )
     ( surrounded by apos, good, return )
-    1+ C@ 1                             ( n 1 )
+    2+ C@ 1                             ( n 1 )
 ;
 

blk/360

@@ -1,15 +1,10 @@
 : (parseh)          ( a -- n f )
-    ( '0': ASCII 0x30 'x': 0x78 0x7830: 30768 )
-    DUP @ 30768 = NOT IF 0 EXIT THEN    ( a 0 )
+    ( '0': ASCII 0x30 'x': 0x78 0x7830 )
+    DUP 1+ @ 0x7830 = NOT IF 0 EXIT THEN ( a 0 )
     ( We have "0x" prefix )
-    2+
-    0  ( a r )
-    BEGIN
-    SWAP C@+                            ( r a+1 c )
-    ?DUP NOT IF DROP 1 EXIT THEN        ( r, 1 )
-    _                                   ( r a n )
-    DUP 0< IF ROT 2DROP 0 EXIT THEN     ( a 0 )
-    ROT 16 * +                          ( a r*16+n )
-    AGAIN
-;
-
+    DUP C@ ( a len )
+    0 SWAP 1+ ( len+1 ) 3 DO ( a r )
+        OVER I + C@ ( a r c ) _ ( a r n )
+        DUP 0< IF 2DROP 0 UNLOOP EXIT THEN
+        SWAP 4 LSHIFT + ( a r*16+n ) LOOP
+    NIP 1 ;

blk/362

@@ -1,16 +1,10 @@
 : (parseb)          ( a -- n f )
-    ( '0': ASCII 0x30 'b': 0x62 0x6230: 25136 )
-    DUP @ 25136 = NOT IF 0 EXIT THEN    ( a 0 )
+    ( '0': ASCII 0x30 'b': 0x62 0x6230 )
+    DUP 1+ @ 0x6230 = NOT IF 0 EXIT THEN ( a 0 )
     ( We have "0b" prefix )
-    2+
-    0  ( a r )
-    BEGIN
-    SWAP C@+                               ( r a+1 c )
-    ?DUP NOT IF DROP 1 EXIT THEN           ( r 1 )
-    _                                      ( r a n )
-    DUP 0< IF ROT 2DROP 0 EXIT THEN        ( a 0 )
-    ROT 2 * +                              ( a r*2+n )
-    AGAIN
-;
-
-
+    DUP C@ ( a len )
+    0 SWAP 1+ ( len+1 ) 3 DO ( a r )
+        OVER I + C@ ( a r c ) _ ( a r n )
+        DUP 0< IF 2DROP 0 UNLOOP EXIT THEN
+        SWAP 1 LSHIFT + ( a r*2+n ) LOOP
+    NIP 1 ;

blk/366

@@ -1,13 +1,13 @@
 ( Read word from C<, copy to WORDBUF, null-terminate, and
   return WORDBUF. )
+: _wb 0x0e RAM+ ;
+: _eot 0x0401 _wb ! _wb ;
 : WORD
-    0x0e RAM+ TOWORD ( a c )
-    DUP EOT? IF OVER ! EXIT THEN
+    _wb 1+ TOWORD ( a c )
+    DUP EOT? IF 2DROP _eot EXIT THEN
     BEGIN
-        ( We take advantage of the fact that char MSB is
-          always zero to pre-write our null-termination )
-        OVER ! 1+ C< ( a c )
-        OVER 0x2d ( 2e-1 for NULL ) RAM+ = OVER WS? OR
+        OVER C! 1+ C< ( a c )
+        OVER 0x2e RAM+ = OVER WS? OR
     UNTIL ( a c )
-    NIP 0x0e RAM+ ( ws a )
-    SWAP EOT? IF 4 OVER ! THEN ;
+    SWAP _wb - 1- ( ws len ) _wb C!
+    EOT? IF _eot ELSE _wb THEN ;

blk/367

@@ -0,0 +1,9 @@
+: IMMEDIATE
+    CURRENT @ 1-
+    DUP C@ 128 OR SWAP C! ;
+: IMMED? 1- C@ 0x80 AND ;
+: +! TUCK @ + SWAP ! ;
+: -^ SWAP - ;
+: / /MOD NIP ;
+: MOD /MOD DROP ;
+: ALLOT HERE +! ;

blk/368

@@ -1,12 +0,0 @@
-: +! TUCK @ + SWAP ! ;
-: [entry] ( w -- )
-    H@ SWAP
-    BEGIN C@+ ( w+1 c ) ?DUP IF C, 0 ELSE 1 THEN UNTIL DROP
-    H@ SWAP - ( sz )
-    ( write prev value )
-    H@ CURRENT @ - ,
-    C, ( write size )
-    H@ CURRENT !
-;
-
-: (entry) WORD [entry] ;

blk/369

@@ -1,11 +1,12 @@
-: IMMEDIATE
-    CURRENT @ 1-
-    DUP C@ 128 OR SWAP C! ;
-: IMMED? 1- C@ 0x80 AND ;
-: -^ SWAP - ;
-: / /MOD NIP ;
-: MOD /MOD DROP ;
-: ALLOT HERE +! ;
-: CREATE (entry) 11 ( 11 == cellWord ) C, ;
-: VARIABLE CREATE 2 ALLOT ;
-: LEAVE R> R> DROP I 1- >R >R ;
+: '? WORD FIND ;
+: '
+    '? (?br) [ 4 , ] EXIT
+    LIT< (wnf) FIND DROP EXECUTE
+;
+: ROLL
+    ?DUP NOT IF EXIT THEN
+    1+ DUP PICK          ( n val )
+    SWAP 2 * (roll)      ( val )
+    NIP ;
+: 2OVER 3 PICK 3 PICK ;
+: 2SWAP 3 ROLL 3 ROLL ;

blk/370

@@ -1,12 +1,14 @@
-: '? WORD FIND ;
-: '
-    '? (?br) [ 4 , ] EXIT
-    LIT< (wnf) FIND DROP EXECUTE
-;
-: ROLL
-    ?DUP NOT IF EXIT THEN
-    1+ DUP PICK          ( n val )
-    SWAP 2 * (roll)      ( val )
-    NIP ;
-: 2OVER 3 PICK 3 PICK ;
-: 2SWAP 3 ROLL 3 ROLL ;
+: MOVE ( a1 a2 u -- )
+    ( u ) 0 DO ( a1 a2 )
+        SWAP C@+ ( a2 a1+1 x )
+        ROT C!+ ( a1+1 a2+1 )
+    LOOP 2DROP ;
+: MOVE- ( a1 a2 u -- )
+    TUCK + 1- ( a1 u a2+u-1 )
+    ROT 2 PICK + 1- ( u a2+u-1 a1+u-1 )
+    ROT ( u ) 0 DO ( a2 a1 )
+        C@- ( a2 a1-1 x )
+        ROT C!- ( a1-1 a2-1 ) SWAP ( a2 a1 )
+    LOOP 2DROP ;
+: MOVE, ( a u -- ) H@ OVER ALLOT SWAP MOVE ;
+: PREV 3 - DUP @ - ;

blk/371

@@ -1,14 +1,10 @@
-: MOVE ( a1 a2 u -- )
-    ( u ) 0 DO ( a1 a2 )
-        SWAP C@+ ( a2 a1+1 x )
-        ROT C!+ ( a1+1 a2+1 )
-    LOOP 2DROP ;
-: MOVE- ( a1 a2 u -- )
-    TUCK + 1- ( a1 u a2+u-1 )
-    ROT 2 PICK + 1- ( u a2+u-1 a1+u-1 )
-    ROT ( u ) 0 DO ( a2 a1 )
-        C@- ( a2 a1-1 x )
-        ROT C!- ( a1-1 a2-1 ) SWAP ( a2 a1 )
-    LOOP 2DROP ;
-: MOVE, ( a u -- ) H@ OVER ALLOT SWAP MOVE ;
-: PREV 3 - DUP @ - ;
+: [entry] ( w -- )
+    C@+ ( w+1 len ) TUCK MOVE, ( len )
+    ( write prev value )
+    H@ CURRENT @ - ,
+    C, ( write size )
+    H@ CURRENT !
+;
+: (entry) WORD [entry] ;
+: CREATE (entry) 11 ( 11 == cellWord ) C, ;
+: VARIABLE CREATE 2 ALLOT ;

blk/381

@@ -1,13 +1,7 @@
 : EMIT
     ( 0x53==(emit) override )
     0x53 RAM+ @ ?DUP IF EXECUTE ELSE (emit) THEN ;
-: (print)
-    BEGIN
-        C@+      ( a+1 c )
-        ( exit if null or 0xd )
-        DUP 0xd = OVER NOT OR IF 2DROP EXIT THEN
-        EMIT     ( a )
-    AGAIN ;
+: (print) C@+ ( a len ) 0 DO C@+ EMIT LOOP DROP ;
 : BS 8 EMIT ; : LF 10 EMIT ; : CR 13 EMIT ;
 : CRLF CR LF ; : SPC 32 EMIT ;
 : NL 0x0a RAM+ @ ( NLPTR ) ?DUP IF EXECUTE ELSE CRLF THEN ;

blk/382

@@ -2,6 +2,9 @@
     BEGIN
         C< DUP 34 ( ASCII " ) = IF DROP EXIT THEN C,
     AGAIN ;
-: LIT" 34 , ( litWord ) ," 0 C, ; IMMEDIATE
+: LIT"
+    34 , ( litWord ) H@ 0 C, ,"
+    DUP H@ -^ 1- ( a len ) SWAP C!
+; IMMEDIATE
 : ." [COMPILE] LIT" COMPILE (print) ; IMMEDIATE
 : ABORT" [COMPILE] ." COMPILE ABORT ; IMMEDIATE

blk/392

@@ -1,6 +1,6 @@
 : INTERPRET
     BEGIN
-    WORD DUP C@ EOT? IF DROP EXIT THEN
+    WORD DUP @ 0x0401 = ( EOT ) IF DROP EXIT THEN
     FIND NOT IF (parse) ELSE EXECUTE THEN
     C<? NOT IF SPC LIT< ok (print) NL THEN
     AGAIN ;

blk/399

@@ -1,4 +1,4 @@
-: LIT< WORD 34 , BEGIN C@+ DUP C, NOT UNTIL DROP ; IMMEDIATE
+: LIT< WORD 34 , DUP C@ 1+ MOVE, ; IMMEDIATE
 : BEGIN H@ ; IMMEDIATE
 : AGAIN COMPILE (br) H@ - _bchk , ; IMMEDIATE
 : UNTIL COMPILE (?br) H@ - _bchk , ; IMMEDIATE

emul/stage.c

@@ -42,7 +42,8 @@ static uint8_t iord_stdio()
 
 static void iowr_stdio(uint8_t val)
 {
-    // we don't output stdout in stage0
+    // uncomment when you need to debug staging
+    // putc(val, stderr);
 }
 
 static void iowr_here(uint8_t val)