pcat: it works!

Forth intepreter now works! There's still DOES> and overflow checks
to implement, but otherwise, we have it!

blk/369

@@ -1,8 +1,5 @@
 : '? WORD FIND ;
-: '
-    '? (?br) [ 4 , ] EXIT
-    LIT< (wnf) FIND DROP EXECUTE
-;
+: ' '? NOT IF LIT< (wnf) FIND DROP EXECUTE THEN ;
 : ROLL
     ?DUP NOT IF EXIT THEN
     1+ DUP PICK          ( n val )

blk/811

@@ -4,7 +4,9 @@ ORG @ 0x25 + HERE ! ( bypass BPB )
 L1 FSET ( start )
 CLI, CLD, AX 0x800 MOVxI, DS AX MOVsx, ES AX MOVsx,
 SS AX MOVsx, STI,
-AH 2 MOVri, DX 0 MOVxI, CH 0 MOVri, CL 2 MOVri, AL 7 MOVri,
-BX 0 MOVxI, 0x13 INT, ( read sectors 2-9 of boot floppy )
+AH 2 MOVri, DX 0 MOVxI, CH 0 MOVri, CL 2 MOVri, AL 12 MOVri,
+BX 0 MOVxI, 0x13 INT, ( read sectors 2-14 of boot floppy )
+( TODO: reading 12 sectors like this probably doesn't work
+  on real vintage PC/AT with floppy. Make this more robust. )
 0x800 0 JMPf,
 ORG @ 0x1fe + HERE ! 0x55 A, 0xaa A,

blk/813

@@ -9,7 +9,7 @@ H@ XCURRENT ! ( set current tip of dict, 0x42 )
 CODE (br) ( 0x53 ) L2 BSET ( used in br? )
     DI DX MOVxx, DI [DI] MOVx[], DX DI ADDxx,
 ;CODE NOP, NOP,
-CODE (br?) ( 0x67 )
+CODE (?br) ( 0x67 )
     AX POPx, AX AX ORxx, JZ, L2 @ RPCs, ( False, branch )
     ( True, skip next 2 bytes and don't branch )
     L1 BSET ( loop will jump here ) DX INCx, DX INCx,

blk/818

@@ -2,4 +2,4 @@
         DI 3 SUBxi, AX [DI] MOVx[], ( prev )
         AX AX ORxx,
     JNZ, AGAIN, ( loop )
-    AX INCx, ( NZ ) RETn,
+    SI DECx, ( start of string, and NZ ) RETn,

blk/823

@@ -6,8 +6,8 @@ CODE *
     AX PUSHx,
 ;CODE
 CODE /MOD
-    BX POPx, AX POPx,
-    BL DIVr, ( TODO: use DIVx, risk of 8086 error )
-    BH BH XORrr, BL AH MOVrr, BX PUSHx, ( modulo )
-    BL AL MOVrr, BX PUSHx, ( division )
+    BX POPx, AX POPx, DX PUSHx, ( protect )
+    DX DX XORxx, BX DIVx,
+    BX DX MOVxx, DX POPx, ( unprotect )
+    BX PUSHx, ( modulo ) AX PUSHx, ( division )
 ;CODE

recipes/pcat/xcomp.fs

@@ -9,11 +9,12 @@ RS_ADDR 0x80 - CONSTANT RAMSTART
 CODE (emit)
     AX POPx, AH 0x0e MOVri, ( print char ) 0x10 INT,
 ;CODE
-CODE (key) AH AH XORrr, 0x16 INT, AX PUSHx, ;CODE
-: FOO (key) (emit) ;
-: BOOT 0x08 @ LIT< FOO _find DROP EXECUTE BYE ;
+CODE (key)
+    AH AH XORrr, 0x16 INT, AH AH XORrr, AX PUSHx, ;CODE
+380 LOAD  ( xcomp core high )
 (entry) _
 ( Update LATEST )
 PC ORG @ 8 + !
+EOT,
 ORG @ 256 /MOD 2 PC! 2 PC!
 H@ 256 /MOD 2 PC! 2 PC!