pcat: begin implementing find

Not comparing strings yet. Without asm tooling support, it's a big
chunk to swallow at once. It's progressing well!

blk/750

@@ -1 +1 @@
-1 7 LOADR+
+1 8 LOADR+

blk/753

@@ -1,9 +1,13 @@
 : OP1 CREATE C, DOES> C@ A, ;
-0xac OP1 LODSB,      0xfa OP1 CLI,       0xfb OP1 STI,
+0xc3 OP1 RETn,       0xfa OP1 CLI,       0xfb OP1 STI,
 0xf4 OP1 HLT,        0xfc OP1 CLD,       0xfd OP1 STD,
 ( no argument, jumps with relative addrs are special )
 0xeb OP1 JMPs,       0xe9 OP1 JMPn,      0x74 OP1 JZ,
-                     0xe8 OP1 CALLn,
+0x75 OP1 JNZ,        0xe8 OP1 CALLn,
+0xf3 OP1 REPZ,       0xf2 OP1 REPNZ,     0xac OP1 LODSB,
+0xa6 OP1 CMPSB,      0xa4 OP1 MOVSB,     0xae OP1 SCASB,
+0xaa OP1 STOSB,
 
-: OPrr CREATE C, DOES> C@ A, 3 LSHIFT OR 0xc0 OR A, ;
+: OP1r CREATE C, DOES> C@ + A, ;
-0x31 OPrr XORxx,     0x30 OPrr XORrr,    0x08 OPrr ORrr,
+0x40 OP1r INCx,      0x48 OP1r DECx,
+0x58 OP1r POPx,      0x50 OP1r PUSHx,

blk/754

@@ -1,9 +1,5 @@
-: MOVri, SWAP 0xb0 OR A, A, ;
+: OPrr CREATE C, DOES> C@ A, 3 LSHIFT OR 0xc0 OR A, ;
-: MOVxi, SWAP 0xb8 OR A, A,, ;
+0x31 OPrr XORxx,     0x30 OPrr XORrr,
-: MOVsx, 0x8e A, SWAP 3 LSHIFT OR 0xc0 OR A, ;
+0x88 OPrr MOVrr,     0x89 OPrr MOVxx,    0x28 OPrr SUBrr,
-: MOVxm, 0x8b A, SWAP 3 LSHIFT 0x6 OR A, A,, ;
+0x29 OPrr SUBxx,     0x08 OPrr ORrr,     0x09 OPrr ORxx,
-: MOVr[], 0x8a A, SWAP 3 LSHIFT OR A, ;
+0x3a OPrr CMPrr,     0x3b OPrr CMPxx,
-: INCx, 0x40 OR A, ;
-: INT, 0xcd A, A, ;
-: JMPr, 0xff A, 7 AND 0xe0 OR A, ;
-: JMPf, ( seg off ) 0xea A, SPLITB A, A, A,, ;

blk/755

@@ -1,16 +1,11 @@
-( Place BEGIN, where you want to jump back and AGAIN after
+: OPrm CREATE C, DOES> C@ A, SWAP 3 LSHIFT OR A, ;
-  a relative jump operator. Just like BSET and BWR. )
+0x8a OPrm MOVr[],    0x8b OPrm MOVx[],
-: BEGIN, PC ;
+
-: BSET PC SWAP ! ;
+: MOVri, SWAP 0xb0 OR A, A, ;
-( same as BSET, but we need to write a placeholder )
+: MOVxi, SWAP 0xb8 OR A, A,, ;
-( : FJR, PC 0 A, ;
+: MOVsx, 0x8e A, SWAP 3 LSHIFT OR 0xc0 OR A, ;
-: IFZ, JRNZ, FJR, ;
+: MOVxm, 0x8b A, SWAP 3 LSHIFT 0x6 OR A, A,, ;
-: IFNZ, JRZ, FJR, ;
+: INT, 0xcd A, A, ;
-: IFC, JRNC, FJR, ;
+: ADDAXi, 0x05 A, A,, ; : ADDALi, 0x04 A, A, ;
-: IFNC, JRC, FJR, ; )
+: JMPr, 0xff A, 7 AND 0xe0 OR A, ;
-: THEN,
+: JMPf, ( seg off ) 0xea A, SPLITB A, A, A,, ;
-    DUP PC          ( l l pc )
-    -^ 1-           ( l off )
-    ( warning: l is a PC offset, not a mem addr! )
-    SWAP ORG @ + BIN( @ - ( off addr )
-    C! ;

blk/756

@@ -1,10 +1,16 @@
-: FWRs BSET 0 A, ;
+( Place BEGIN, where you want to jump back and AGAIN after
-: FSET @ THEN, ;
+  a relative jump operator. Just like BSET and BWR. )
-( : BREAK, FJR, 0x8000 OR ;
+: BEGIN, PC ;
-: BREAK?, DUP 0x8000 AND IF
+: BSET PC SWAP ! ;
-        0x7fff AND 1 ALLOT THEN, -1 ALLOT
+( same as BSET, but we need to write a placeholder )
-    THEN ; )
+: FJR, PC 0 A, ;
-: RPCs, PC - 1- A, ; : RPCn, PC - 2- A,, ;
+: IFZ, JNZ, FJR, ;
-: AGAIN, ( BREAK?, ) RPCs, ;
+: IFNZ, JZ, FJR, ;
-( Use RPCx with appropriate JMP/CALL op. Example:
+( : IFC, JRNC, FJR, ;
-  JMPs, 0x42 RPCs, or CALLn, 0x1234 RPCn, )
+: IFNC, JRC, FJR, ; )
+: THEN,
+    DUP PC          ( l l pc )
+    -^ 1-           ( l off )
+    ( warning: l is a PC offset, not a mem addr! )
+    SWAP ORG @ + BIN( @ - ( off addr )
+    C! ;

blk/757

@@ -1,4 +1,10 @@
-: CODE ( same as CREATE, but with native word )
+: FWRs BSET 0 A, ;
-    (entry)
+: FSET @ THEN, ;
-    23 C, ( 23 == nativeWord ) ;
+( : BREAK, FJR, 0x8000 OR ;
-: ;CODE ;
+: BREAK?, DUP 0x8000 AND IF
+        0x7fff AND 1 ALLOT THEN, -1 ALLOT
+    THEN ; )
+: RPCs, PC - 1- A, ; : RPCn, PC - 2- A,, ;
+: AGAIN, ( BREAK?, ) RPCs, ;
+( Use RPCx with appropriate JMP/CALL op. Example:
+  JMPs, 0x42 RPCs, or CALLn, 0x1234 RPCn, )

blk/758

@@ -0,0 +1,4 @@
+: CODE ( same as CREATE, but with native word )
+    (entry)
+    23 C, ( 23 == nativeWord ) ;
+: ;CODE ;

blk/813

@@ -8,8 +8,6 @@ H@ XCURRENT !        ( set current tip of dict, 0x42 )
     0x17 A,          ( nativeWord )
 ;CODE
 CODE FOO
-( Update LATEST, temporarily hackish )
-PC 1- ORG @ 8 + !
     AH 0x0e MOVri, ( print char ) AL 'X' MOVri, 0x10 INT,
     L2 BSET JMPs, L2 @ RPCs,
 ;CODE

blk/814

@@ -3,6 +3,3 @@ L1 BSET PC 3 - ORG @ 0x34 + ! ( execute -- BX -> wordref )
     AL [BX] MOVr[],
     BX INCx, ( PFA )
     AX JMPr,
-
-PC 3 - ORG @ 1+ ! ( main )
-    BX 0x08 MOVxm, ( LATEST ) JMPs, L1 @ RPCs, ( execute )

blk/815

@@ -0,0 +1,14 @@
+L4 BSET PC 3 - ORG @ 4 + ! ( find )
+( find word the same name as str in SI starting from tip in
+  BX. Returns wordref in BX. Z if found, NZ if not. )
+    CH CH XORrr, CL [SI] MOVr[], ( CX -> strlen )
+    SI INCx,
+    AX AX XORxx, ( initial prev )
+    BEGIN, ( inner )
+        BX AX SUBxx, ( jump to prev wordref )
+        BX DECx, AL [BX] MOVr[], ( strlen )
+        CL AL CMPrr, IFZ, BX INCx, RETn, THEN,
+        BX DECx, BX DECx, AX [BX] MOVx[], ( prev )
+        AX AX ORxx,
+    JNZ, AGAIN,
+    BEGIN, JMPs, AGAIN,

blk/816

@@ -0,0 +1,6 @@
+L3 BSET 3 A, 'F' A, 'O' A, 'O' A,
+PC 3 - ORG @ 1+ ! ( main )
+    BX 0x08 MOVxm, ( LATEST )
+    SI L3 @ MOVxi,
+    CALLn, L4 @ RPCn, ( find )
+    JMPs, L1 @ RPCs, ( execute )

recipes/pcat/xcomp.fs

@@ -1,6 +1,9 @@
 750 LOAD  ( 8086 asm )
 262 LOAD  ( xcomp )
 270 LOAD  ( xcomp overrides )
-812 814 LOADR
+812 816 LOADR
+(entry) _
+( Update LATEST )
+PC ORG @ 8 + !
 ORG @ 256 /MOD 2 PC! 2 PC!
 H@ 256 /MOD 2 PC! 2 PC!