pcat: begin porting forth

I'm not sure yet where I'm going, but I'm not going to build the
8086 port from the ground up like I did with the z80, that is,
making is sustain itself and eventually merge its forth code with
core words. That would be too much work which would then be thrown
out (all those words I'll initially have to implement in asm which
are already implemented in Forth).

What I *think* I can do is build a mirror version of z80 boot code
and cross-compile it from the z80. This means it has to follow z80
stable ABI.

Nope, I'm not sure where I'm going...

blk/752

@@ -4,3 +4,4 @@
 ;
 : PC H@ ORG @ - BIN( @ + ;
 : A, C, ;
+: A,, SPLITB A, A, ;

blk/753

@@ -1,12 +1,13 @@
 : OP1 CREATE C, DOES> C@ A, ;
 0xac OP1 LODSB,      0xfa OP1 CLI,       0xfb OP1 STI,
 0xf4 OP1 HLT,        0xfc OP1 CLD,       0xfd OP1 STD,
-( no argument, jumps with abs addrs are special )
+( no argument, jumps with relative addrs are special )
 0xeb OP1 JMPs,       0xe9 OP1 JMPn,      0x74 OP1 JZ,
 : MOVri, SWAP 0xb0 OR A, A, ;
 : MOVxi, SWAP 0xb8 OR A, SPLITB A, A, ;
 : MOVsx, 0x8e A, SWAP 3 LSHIFT OR 0xc0 OR A, ;
 : INT, 0xcd A, A, ;
 : JMPr, 0xff A, 7 AND 0xe0 OR A, ;
+: JMPf, ( seg off ) 0xea A, SPLITB A, A, SPLITB A, A, ;
 : OPrr CREATE C, DOES> C@ A, 3 LSHIFT OR 0xc0 OR A, ;
 0x31 OPrr XORxx,     0x08 OPrr ORrr,

blk/811

@@ -2,9 +2,9 @@ H@ ORG ! 0x7c00 BIN( ! ( BIOS loads boot bin at 0x7c00 )
 JMPs, L1 FWRs ( start )
 ORG @ 0x25 + HERE ! ( bypass BPB )
 L1 FSET ( start )
-CLI, CLD, AX AX XORxx, DS AX MOVsx, ES AX MOVsx,
+CLI, CLD, AX 0x800 MOVxi, DS AX MOVsx, ES AX MOVsx,
 SS AX MOVsx, SP 0xffff MOVxi, STI,
 AH 2 MOVri, DX 0 MOVxi, CH 0 MOVri, CL 2 MOVri, AL 1 MOVri,
-BX 0x8000 MOVxi, 0x13 INT, ( read 2nd sector of boot floppy )
-BX JMPr,
+BX 0 MOVxi, 0x13 INT, ( read 2nd sector of boot floppy )
+0x800 0 JMPf,
 ORG @ 0x1fe + HERE ! 0x55 A, 0xaa A,

blk/812

@@ -1,10 +1,16 @@
-H@ ORG ! 0x8000 BIN( !
-JMPs, L1 FWRs ( start )
-L2 ( msg ) BSET ," Hello World!" 0 A,
-L1 FSET ( start )
-SI L2 @ ( msg ) MOVxi, AH 0x0e MOVri, ( print char )
-L1 BSET ( loop ) LODSB, AL AL ORrr, ( end of str? )
-JZ, L2 FWRs ( next ) 0x10 INT, ( print char )
-JMPs, L1 ( loop ) BWR
-L2 FSET ( next ) AH 0 MOVri, 0x16 INT, ( read kbd )
-AH 0x0e MOVri, 0x10 INT, ( spit read char ) HLT, ( done )
+( Registers. SP -> PSP DX -> RSP CX -> IP )
+H@ ORG !
+JMPn, 0 A,,   ( 00, main )     JMPn, 0 A,,   ( 03, find )
+0 A,,         ( 06, unused )   0 A,,         ( 08, LATEST )
+0 A,          ( 0a, unused )   JMPn, 0 A,,   ( 0b, cellWord )
+JMPn, 0 A,, ( 0e compiledWord ) JMPn, 0 A,,  ( 11, pushRS )
+JMPn, 0 A,,   ( 14, popRS )
+JMPn, 0 A,,   ( 17, nativeWord )
+JMPn, 0 A,,   ( 1a, next )     JMPn, 0 A,,   ( 1d, chkPS )
+0 A, 0 A,     ( 20, numberWord ) 0 A, 0 A,   ( 22, litWord )
+0 A, 0 A,     ( 24, addrWord ) 0 A, 0 A,     ( 26, unused )
+0 A, 0 A,,    ( unused )
+JMPn, 0 A,,   ( 2b, doesWord ) 0 A, 0 A,     ( 2e, unused )
+0 A, 0 A,,    ( unused )
+JMPn, 0 A,,   ( 33, execute )  0 A, 0 A,     ( unused )
+0 A, 0 A,,    ( unused )

blk/813

@@ -0,0 +1,3 @@
+PC 3 - ORG @ 1+ ! ( main )
+    AH 0x0e MOVri, ( print char ) AL 'X' MOVri, 0x10 INT,
+    HLT,

recipes/pcat/xcomp.fs

@@ -1,4 +1,4 @@
 750 LOAD
-812 LOAD
+812 813 LOADR
 ORG @ 256 /MOD 2 PC! 2 PC!
 H@ 256 /MOD 2 PC! 2 PC!