Clarify signed-ness

And fix broken negative display in ".".

blk/003

@@ -9,4 +9,4 @@ Contents
 
  4 DOES>                        6 Compilation vs meta-comp.
  8 I/O                         11 Chained comparisons
-14 Addressed devices
+14 Addressed devices           18 Signed-ness

blk/018

@@ -0,0 +1,9 @@
+Signed-ness
+
+For simplicity purposes, numbers are generally considered
+unsigned. For convenience, decimal parsing and formatting
+support the "-" prefix, but under the hood, it's all unsigned.
+
+This leads to some oddities. For example, "-1 0 <" is false.
+To compare whether something is negative, use the "<0" word
+which is the equivalent to "0x7fff >".

blk/058

@@ -5,6 +5,6 @@ LIT    --         Write a LIT entry. You're expected to write
 LIT< x --         Read following word and write to HERE as a
                   string literal.
 LITS   a --       Write word at addr a as a atring literal.
-SCMP   a1 a2 -- n Compare strings a1 and a2. See CMP
+S=     a1 a2 -- f Returns whether string a1 == a2.
 SCPY   a --       Copy string at addr a into HERE.
 SLEN   a -- n     Push length of str at a.

emul/Makefile

@@ -22,6 +22,8 @@ all: $(TARGETS)
 
 $(BLKPACK):
 	$(MAKE) -C ../tools
+
+.PHONY: $(STRIPFC) $(SLATEST) $(BIN2C)
 $(STRIPFC): $(BLKPACK)
 $(SLATEST): $(BLKPACK)
 $(BIN2C): $(BLKPACK)

emul/forth/forth.c

@@ -118,7 +118,9 @@ int main(int argc, char *argv[])
         tcsetattr(0, TCSAFLUSH, &termInfo);
         emul_printdebug();
     }
+    if (blkfp != NULL) {
         fclose(blkfp);
+    }
     fclose(fp);
     return retcode;
 }

forth/boot.fs

@@ -27,7 +27,7 @@ NOP, NOP,         ( 20, numberWord )
 NOP, NOP,         ( 22, litWord )
 NOP, NOP,         ( 24, addrWord )
 NOP, NOP,         ( 26, unused )
-0 JPnn,           ( 28, flagsToBC )
+RAMSTART 0x4e + JPnn, ( 28, RST 28 )
 0 JPnn,           ( 2b, doesWord )
 NOP, NOP,         ( 2e, unused )
 RAMSTART 0x4e + JPnn, ( RST 30 )
@@ -201,7 +201,7 @@ L4 FSET L3 FSET ( loopend )
     ( HL is prev field's addr. Is offset zero? )
     A D LDrr,
     E ORr,
-    IFZ, ( noprev )
+    IFNZ, ( noprev )
         ( get absolute addr from offset )
         ( carry cleared from "or e" )
         DE SBCHLss,
@@ -218,16 +218,6 @@ L4 FSET ( end )
     BC POPqq,
     RET,
 
-PC ORG @ 0x29 + ! ( flagsToBC )
-    BC 0 LDddnn,
-    CZ RETcc, ( equal )
-    BC INCss,
-    CC RETcc, ( > )
-    ( < )
-    BC DECss,
-    BC DECss,
-    RET,
-
 PC ORG @ 0x12 + ! ( pushRS )
     IX INCss,
     IX INCss,

forth/cmp.fs

@@ -2,6 +2,8 @@
 
 : >= < NOT ;
 : <= > NOT ;
+: <0 32767 > ;
+: >=0 <0 NOT ;
 
 ( n1 -- n1 true )
 : <>{ 1 ;

forth/core.fs

@@ -18,7 +18,7 @@
 : BEGIN H@ ; IMMEDIATE
 : AGAIN COMPILE (br) H@ - , ; IMMEDIATE
 : UNTIL COMPILE (?br) H@ - , ; IMMEDIATE
-: ( BEGIN LIT< ) WORD SCMP NOT UNTIL ; IMMEDIATE
+: ( BEGIN LIT< ) WORD S= UNTIL ; IMMEDIATE
 ( Hello, hello, krkrkrkr... do you hear me?
   Ah, voice at last! Some lines above need comments
   BTW: Forth lines limited to 64 cols because of default

forth/fmt.fs

@@ -12,9 +12,7 @@
 
 : .               ( n -- )
     ( handle negative )
-    ( that "0 1 -" thing is because we don't parse negative
-      number correctly yet. )
-    DUP 0 < IF '-' EMIT 0 1 - * THEN
+    DUP <0 IF '-' EMIT -1 * THEN
     _
     BEGIN
     DUP '9' > IF DROP EXIT THEN ( stop indicator, we're done )

forth/icore.fs

@@ -52,37 +52,52 @@
 : < CMP -1 = ;
 : > CMP 1 = ;
 
+( r c -- r f )
+( Parse digit c and accumulate into result r.
+  Flag f is 0 when c was a valid digit, 1 when c was WS,
+  -1 when c was an invalid digit. )
+: _pdacc
+    DUP 0x21 < IF DROP 1 EXIT THEN
+    ( parse char )
+    '0' -
+    ( if bad, return "r -1" )
+    DUP 0 < IF DROP -1 EXIT THEN   ( bad )
+    DUP 9 > IF DROP -1 EXIT THEN   ( bad )
+    ( good, add to running result )
+    SWAP 10 * +                    ( r*10+n )
+    0                              ( good )
+;
+
 : (parsed)      ( a -- n f )
     ( read first char outside of the loop. it *has* to be
       nonzero. )
     DUP C@                        ( a c )
-    DUP NOT IF EXIT THEN      ( a 0 )
     ( special case: do we have a negative? )
     DUP '-' = IF
         ( Oh, a negative, let's recurse and reverse )
         DROP 1 +                  ( a+1 )
         (parsed)                  ( n f )
-        SWAP 0 SWAP               ( f 0 n )
+        0 ROT                     ( f 0 n )
         - SWAP EXIT               ( 0-n f )
     THEN
-    ( running result, staring at zero )
+    ( running result from first char )
     0 SWAP                               ( a r c )
-    ( Loop over chars )
-    BEGIN
-    ( parse char )
-    '0' -
-    ( if bad, return "a 0" )
-    DUP 0 < IF 2DROP 0 EXIT THEN   ( bad )
-    DUP 9 > IF 2DROP 0 EXIT THEN   ( bad )
-    ( good, add to running result )
-    SWAP 10 * +                    ( a r*10+n )
-    SWAP 1 + SWAP                  ( a+1 r )
-    ( read next char )
-    OVER C@
-    DUP NOT UNTIL
-    ( we're done and it's a success. We have "a r c", we want
-      "r 1". )
-    DROP SWAP DROP 1
+    _pdacc                               ( a r f )
+    DUP IF
+        ( first char was not a valid digit )
+        2DROP 0 EXIT                     ( a 0 )
+    THEN
+    BEGIN                         ( a r 0 )
+        DROP SWAP 1 +             ( r a+1 )
+        DUP C@                    ( r a c )
+        ROT SWAP                  ( a r c )
+        _pdacc                    ( a r f )
+    DUP UNTIL
+    ( a r f -- f is 1 on success, -1 on error, normalize
+      to bool. )
+    1 =         ( a r f )
+    ( we want "r f" )
+    ROT DROP
 ;
 
 ( This is only the "early parser" in earlier stages. No need

forth/z80a.fs

@@ -372,10 +372,10 @@
 : BWR @ AGAIN, ;
 ( same as BSET, but we need to write a placeholder )
 : FJR, PC 0 A, ;
-: IFZ, JRZ, FJR, ;
-: IFNZ, JRNZ, FJR, ;
-: IFC, JRC, FJR, ;
-: IFNC, JRNC, FJR, ;
+: IFZ, JRNZ, FJR, ;
+: IFNZ, JRZ, FJR, ;
+: IFC, JRNC, FJR, ;
+: IFNC, JRC, FJR, ;
 : THEN,
     DUP PC          ( l l pc )
     -^ 1 -          ( l off )

forth/z80c.fs

@@ -149,10 +149,10 @@ CODE NOT
     A L LDrr,
     H ORr,
     HL 0 LDddnn,
-    IFNZ, ( skip )
+    IFZ,
         ( false, make 1 )
         HL INCss,
-    THEN, ( skip )
+    THEN,
     HL PUSHqq,
 ;CODE
 
@@ -209,10 +209,10 @@ CODE /MOD
         RLA,
         HL ADCHLss,
         DE SBCHLss,
-        IFNC, ( skip )
+        IFC,
             DE ADDHLss,
             C DECr,
-        THEN, ( skip )
+        THEN,
     DJNZ, AGAIN, ( loop )
     B A LDrr,
     HL PUSHqq,
@@ -311,10 +311,13 @@ CODE (resRS)
     IX RS_ADDR LDddnn,
 ;CODE
 
-CODE SCMP
+CODE S=
     DE  POPqq,
     HL  POPqq,
     chkPS,
+    ( pre-push false )
+    BC 0 LDddnn,
+    BC PUSHqq,
     BEGIN, ( loop )
         LDA(DE),
         (HL) CPr,
@@ -324,10 +327,11 @@ CODE SCMP
         HL INCss,
         DE INCss,
     JRNZ, AGAIN, ( loop )
+    ( success, change false to true )
+    HL POPqq,
+    HL INCss,
+    HL PUSHqq,
 L1 FSET ( end )
-    ( 40 == flagsToBC )
-    40 CALLnn,
-    BC PUSHqq,
 ;CODE
 
 CODE CMP
@@ -335,8 +339,16 @@ CODE CMP
     DE  POPqq,
     chkPS,
     DE SUBHLss,
-    ( 40 == flagsToBC )
-    40 CALLnn,
+    BC 0 LDddnn,
+    IFNZ,
+        ( not equal )
+        BC INCss,
+        IFNC,
+            ( < )
+            BC DECss,
+            BC DECss,
+        THEN,
+    THEN,
     BC PUSHqq,
 ;CODE
 
@@ -347,13 +359,14 @@ CODE _find
     chkPS,
     ( 3 == find )
     3 CALLnn,
-    IFZ, ( found )
+    IFNZ,
         ( not found )
         HL PUSHqq,
         DE 0 LDddnn,
         DE PUSHqq,
         JPNEXT,
-    THEN, ( found )
+    THEN,
+    ( found )
     DE PUSHqq,
     DE 1 LDddnn,
     DE PUSHqq,

tests/forth/test_cmp.fs

@@ -3,3 +3,4 @@
 0x42 <>{ 0x40 &> 0x44 &< <>} #
 0x44 <>{ 0x40 &> 0x44 &< <>} NOT #
 0x22 0x8065 < #
+-1 0 > #