pcat: move drivers and xcomp to blkfs

blk/001

@@ -10,7 +10,7 @@ MASTER INDEX
 550 TI-84+ Recipe             580 RC2014 Recipe
 620 Sega Master System Recipe
 650 AVR assembler             730 8086 assembler
-810 PC/AT Recipe
+800 8086 boot code            830 PC/AT recipe
 
 
 

blk/800

@@ -0,0 +1,16 @@
+8086 boot code
+
+Code in the following blocks assemble into a binary that is
+suitable to plug into Core words (B350) to achieve a fully
+functional Collapse OS. It is structured in a way that is
+very similar to Z80 boot code (B280) and requires the same
+constants to be pre-declared.
+
+RESERVED REGISTERS: SP is reserved for PSP, BP is for RSP and
+DX is for IP. Whenever you use these registers for another
+purpose, be sure to protect their initial value. Like with
+Z80, you can use SP freely in native code, but you have to make
+sure it goes back to its previous level before next is called.
+
+
+                                                        (cont.)

blk/801

@@ -0,0 +1,13 @@
+STABLE ABI: As a compatible binary, this binary follows the
+same stable ABI as its z80 counterpart.
+
+PS CHECKS: Unlike z80 boot code, we don't check PS at each next
+call (we do check RS though). It is the responsibility of every
+native PSP-modifying word to call chkPS, . Also, chkPS, is a
+bit different than in z80: it is parametrizable. The idea is
+that we always call chkPS, before popping, telling the expected
+size of stack. This allows for some interesting optimization.
+For example, in SWAP, no need to pop, chkPS, then push, we can
+chkPS and then proceed to optimized swapping in PS.
+
+To assemble, load blocks 805 through 820.

blk/805

@@ -0,0 +1,15 @@
+VARIABLE lblexec VARIABLE lblnext
+H@ ORG !
+JMPn, 0 A,, ( 00, main ) 0 A, ( 03, boot driveno )
+0 A,, ( 04, BOOT )
+0 A,, ( 06, uflw ) 0 A,, ( 08, LATEST )
+0 A, 0 A, 0 A,, ( unused )
+0 A, 0 A,, ( unused ) JMPn, 0 A,,  ( 11, pushRS )
+JMPn, 0 A,, ( 14, popRS ) 0 A, 0 A,, ( unused )
+JMPn, 0 A,,   ( 1a, next )     0 A, 0 A,,    ( unused )
+0 A, 0 A, 0 A, 0 A,     ( unused )
+0 A, 0 A, 0 A, 0 A,     ( unused )
+0 A, 0 A,, ( unused )
+0 A, 0 A,, 0 A, 0 A, ( unused )
+0 A, 0 A,,    ( unused )
+JMPn, 0 A,, ( 33, execute ) 0 A, 0 A, 0 A, 0 A,, ( unused )

blk/806

@@ -0,0 +1,16 @@
+( BOOT DICT: There are only 3 words in the boot dict, but
+  these words' offset need to be stable, so they're part of
+  the "stable ABI" )
+'E' A, 'X' A, 'I' A, 'T' A, 0 A,, ( prev ) 4 A, ( len )
+H@ XCURRENT ! ( set current tip of dict, 0x42 )
+    0 A, ( native )
+    DX [BP] 0 MOVx[]+, BP DECx, BP DECx, ( popRS )
+;CODE NOP,
+CODE (br) ( 0x53 ) L2 BSET ( used in br? )
+    DI DX MOVxx, DI [DI] MOVx[], DX DI ADDxx,
+;CODE NOP, NOP,
+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,
+;CODE NOP, NOP, NOP, NOP, NOP,

blk/807

@@ -0,0 +1,15 @@
+CODE (loop) ( 0x80 )
+    [BP] 0 INC[w]+, ( I++ )
+    ( Jump if I <> I' )
+    AX [BP] 0 MOVx[]+, AX [BP] -2 CMPx[]+,
+    JNZ, L2 @ RPCs, ( branch )
+    ( don't branch )
+    BP 4 SUBxi, JMPs, L1 @ RPCs,
+ORG @ 0xa3 + HERE !
+CODE 2>R ( 0xa9 )
+    [BP] 4 POP[w]+, [BP] 2 POP[w]+, BP 4 ADDxi,
+;CODE NOP, NOP, NOP, NOP, NOP,
+CODE (n) ( 0xbf, number literal )
+    DI DX MOVxx, DI [DI] MOVx[], DI PUSHx,
+    DX INCx, DX INCx,
+;CODE NOP, NOP,

blk/808

@@ -0,0 +1,6 @@
+CODE (s) ( 0xd4, string literal, see B287 )
+    DI DX MOVxx, ( IP )
+    AH AH XORrr, AL [DI] MOVr[], ( slen )
+    DX PUSHx, DX INCx, DX AX ADDxx,
+;CODE
+( END OF STABLE ABI )

blk/809

@@ -0,0 +1,9 @@
+lblnext BSET PC 0x1d - ORG @ 0x1b + ! ( next )
+    ( RSP check )
+    AX RS_ADDR MOVxI, BP AX CMPxx,
+    IFC, ( BP < RS_ADDR )
+        DI 0x06 MOVxm, JMPs, L1 FWRs ( execute )
+    THEN,
+    DI DX MOVxx, ( <-- IP ) DX INCx, DX INCx,
+    DI [DI] MOVx[], ( wordref )
+    ( continue to execute ) L1 FSET

blk/810

@@ -1,16 +1,15 @@
-PC/AT Recipe
+lblexec BSET PC 0x36 - ORG @ 0x34 + ! ( DI -> wordref )
+    AL [DI] MOVr[], DI INCx, ( PFA )
+    AL AL ORrr, IFZ, DI JMPr, THEN, ( native )
+    AL DECr, IFNZ, ( cell or does )
+        DI PUSHx, ( push PFA )
+        AL DECr, IFZ, ( cell ) JMPs, lblnext @ RPCs, THEN,
+        ( does, see B302 )
+        DI INCx, DI INCx, DI [DI] MOVx[],
+    THEN, ( continue to compiled )
+    ( compiled )
+    BP INCx, BP INCx, [BP] 0 DX MOV[]+x, ( pushRS )
+    DX DI MOVxx, DX INCx, DX INCx, ( --> IP )
+    DI [DI] MOVx[],
+    JMPs, lblexec @ RPCs,
 
-Work in progress.
-
-Register usage: SP is PSP, BP is RSP, DX is IP
-
-Unlike z80 boot code, we don't check PS at each next call (we
-do check RS though). It is the responsibility of every native
-PSP-modifying word to call chkPS, . Also, chkPS, is a bit
-different than in z80: it is parametrizable. The idea is that
-we always call chkPS, before popping, telling the expected size
-of stack. This allows for some interesting optimization. For
-example, in SWAP, no need to pop, chkPS, then push, we can
-chkPS and then proceed to optimized swapping in PS.
-
-811 MBR bootloader             812-829 Boot code

blk/811

@@ -1,12 +1,5 @@
-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 0x800 MOVxI, DS AX MOVsx, ES AX MOVsx,
-SS AX MOVsx, DX PUSHx, ( will be popped by OS ) STI,
-AH 2 MOVri, DH 0 MOVri, CH 0 MOVri, CL 2 MOVri, AL 15 MOVri,
-BX 0 MOVxI, 0x13 INT, ( read sectors 2-15 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,
+lblchkPS BSET ( CX -> expected size )
+    AX PS_ADDR MOVxI, AX SP SUBxx, 2 SUBAXI, ( CALL adjust )
+    AX CX CMPxx,
+    IFNC, ( we're good ) RETn, THEN,
+    ( underflow ) DI 0x06 MOVxm, JMPs, lblexec @ RPCs,

blk/812

@@ -1,15 +1,9 @@
-VARIABLE lblexec VARIABLE lblnext
-H@ ORG !
-JMPn, 0 A,, ( 00, main ) 0 A, ( 03, boot driveno )
-0 A,, ( 04, BOOT )
-0 A,, ( 06, uflw ) 0 A,, ( 08, LATEST )
-0 A, 0 A, 0 A,, ( unused )
-0 A, 0 A,, ( unused ) JMPn, 0 A,,  ( 11, pushRS )
-JMPn, 0 A,, ( 14, popRS ) 0 A, 0 A,, ( unused )
-JMPn, 0 A,,   ( 1a, next )     0 A, 0 A,,    ( unused )
-0 A, 0 A, 0 A, 0 A,     ( unused )
-0 A, 0 A, 0 A, 0 A,     ( unused )
-0 A, 0 A,, ( unused )
-0 A, 0 A,, 0 A, 0 A, ( unused )
-0 A, 0 A,,    ( unused )
-JMPn, 0 A,, ( 33, execute ) 0 A, 0 A, 0 A, 0 A,, ( unused )
+PC 3 - ORG @ 1+ ! ( main )
+    DX POPx, ( boot drive no ) 0x03 DL MOVmr,
+    SP PS_ADDR MOVxI, BP RS_ADDR MOVxI,
+    DI 0x08 MOVxm, ( LATEST )
+( HERE begins at CURRENT )
+    RAMSTART 0x4 ( HERE ) + DI MOVmx,
+    RAMSTART 0x2 ( CURRENT ) + DI MOVmx,
+    DI 0x04 ( BOOT ) MOVxm,
+    JMPn, lblexec @ RPCn, ( execute )

blk/813

@@ -1,16 +1,16 @@
-( BOOT DICT: There are only 3 words in the boot dict, but
-  these words' offset need to be stable, so they're part of
-  the "stable ABI" )
-'E' A, 'X' A, 'I' A, 'T' A, 0 A,, ( prev ) 4 A, ( len )
-H@ XCURRENT ! ( set current tip of dict, 0x42 )
-    0 A, ( native )
-    DX [BP] 0 MOVx[]+, BP DECx, BP DECx, ( popRS )
-;CODE NOP,
-CODE (br) ( 0x53 ) L2 BSET ( used in br? )
-    DI DX MOVxx, DI [DI] MOVx[], DX DI ADDxx,
-;CODE NOP, NOP,
-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,
-;CODE NOP, NOP, NOP, NOP, NOP,
+( native words )
+CODE EXECUTE 1 chkPS,
+    DI POPx, JMPn, lblexec @ RPCn,
+CODE >R 1 chkPS,
+    BP INCx, BP INCx, [BP] 0 POP[w]+,
+;CODE NOP, NOP, NOP,
+CODE R>
+    [BP] 0 PUSH[w]+, BP DECx, BP DECx,
+;CODE
+CODE 2R> 2 chkPS,
+    [BP] -2 PUSH[w]+, [BP] 0 PUSH[w]+, BP 4 SUBxi,
+;CODE
+CODE ROT ( a b c -- b c a ) 3 chkPS,
+    CX POPx, BX POPx, AX POPx,
+    BX PUSHx, CX PUSHx, AX PUSHx,
+;CODE

blk/814

@@ -1,15 +1,12 @@
-CODE (loop) ( 0x80 )
-    [BP] 0 INC[w]+, ( I++ )
-    ( Jump if I <> I' )
-    AX [BP] 0 MOVx[]+, AX [BP] -2 CMPx[]+,
-    JNZ, L2 @ RPCs, ( branch )
-    ( don't branch )
-    BP 4 SUBxi, JMPs, L1 @ RPCs,
-ORG @ 0xa3 + HERE !
-CODE 2>R ( 0xa9 )
-    [BP] 4 POP[w]+, [BP] 2 POP[w]+, BP 4 ADDxi,
-;CODE NOP, NOP, NOP, NOP, NOP,
-CODE (n) ( 0xbf, number literal )
-    DI DX MOVxx, DI [DI] MOVx[], DI PUSHx,
-    DX INCx, DX INCx,
-;CODE NOP, NOP,
+CODE DUP 1 chkPS, AX POPx, AX PUSHx, AX PUSHx, ;CODE
+CODE ?DUP 1 chkPS, AX POPx, AX AX ORxx, AX PUSHx,
+    IFNZ, AX PUSHx, THEN, ;CODE
+CODE DROP 1 chkPS, AX POPx, ;CODE
+CODE SWAP AX POPx, BX POPx, AX PUSHx, BX PUSHx, ;CODE
+CODE OVER ( a b -- a b a ) 2 chkPS,
+    DI SP MOVxx, AX [DI] 2 MOVx[]+, AX PUSHx, ;CODE
+CODE PICK
+    DI POPx, DI SHLx1, ( x2 )
+    CX DI MOVxx, CX 2 ADDxi, CALLn, lblchkPS @ RPCn,
+    DI SP ADDxx, DI [DI] MOVx[], DI PUSHx,
+;CODE

blk/815

@@ -1,6 +1,16 @@
-CODE (s) ( 0xd4, string literal, see B287 )
-    DI DX MOVxx, ( IP )
-    AH AH XORrr, AL [DI] MOVr[], ( slen )
-    DX PUSHx, DX INCx, DX AX ADDxx,
+CODE (roll) ( "2 3 4 5 4 --> 2 4 5 5". See B311 )
+    CX POPx, CX 2 ADDxi, CALLn, lblchkPS @ RPCn, CX 2 SUBxi,
+    SI SP MOVxx, SI CX ADDxx,
+    DI SI MOVxx, DI 2 ADDxi, STD, REPZ, MOVSB,
 ;CODE
-( END OF STABLE ABI )
+CODE 2DROP 2 chkPS, SP 4 ADDxi, ;CODE
+CODE 2DUP 2 chkPS,
+    AX POPx, BX POPx,
+    BX PUSHx, AX PUSHx, BX PUSHx, AX PUSHx,
+;CODE
+CODE S0 AX PS_ADDR MOVxI, AX PUSHx, ;CODE
+CODE 'S SP PUSHx, ;CODE
+CODE AND 2 chkPS,
+    AX POPx, BX POPx, AX BX ANDxx, AX PUSHx, ;CODE
+CODE OR 2 chkPS,
+    AX POPx, BX POPx, AX BX ORxx, AX PUSHx, ;CODE

blk/816

@@ -1,9 +1,15 @@
-lblnext BSET PC 0x1d - ORG @ 0x1b + ! ( next )
-    ( RSP check )
-    AX RS_ADDR MOVxI, BP AX CMPxx,
-    IFC, ( BP < RS_ADDR )
-        DI 0x06 MOVxm, JMPs, L1 FWRs ( execute )
-    THEN,
-    DI DX MOVxx, ( <-- IP ) DX INCx, DX INCx,
-    DI [DI] MOVx[], ( wordref )
-    ( continue to execute ) L1 FSET
+CODE XOR 2 chkPS,
+    AX POPx, BX POPx, AX BX XORxx, AX PUSHx, ;CODE
+CODE NOT 1 chkPS,
+    AX POPx, AX AX ORxx,
+    IFNZ, AX -1 MOVxI, THEN, AX INCx, AX PUSHx,
+;CODE
+CODE + 2 chkPS,
+    AX POPx, BX POPx, AX BX ADDxx, AX PUSHx, ;CODE
+CODE - 2 chkPS,
+    BX POPx, AX POPx, AX BX SUBxx, AX PUSHx, ;CODE
+CODE * 2 chkPS,
+    AX POPx, BX POPx,
+    DX PUSHx, ( protect from MUL ) BX MULx, DX POPx,
+    AX PUSHx,
+;CODE

blk/817

@@ -1,15 +1,16 @@
-lblexec BSET PC 0x36 - ORG @ 0x34 + ! ( DI -> wordref )
-    AL [DI] MOVr[], DI INCx, ( PFA )
-    AL AL ORrr, IFZ, DI JMPr, THEN, ( native )
-    AL DECr, IFNZ, ( cell or does )
-        DI PUSHx, ( push PFA )
-        AL DECr, IFZ, ( cell ) JMPs, lblnext @ RPCs, THEN,
-        ( does, see B302 )
-        DI INCx, DI INCx, DI [DI] MOVx[],
-    THEN, ( continue to compiled )
-    ( compiled )
-    BP INCx, BP INCx, [BP] 0 DX MOV[]+x, ( pushRS )
-    DX DI MOVxx, DX INCx, DX INCx, ( --> IP )
-    DI [DI] MOVx[],
-    JMPs, lblexec @ RPCs,
-
+CODE /MOD 2 chkPS,
+    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
+CODE ! 2 chkPS, DI POPx, AX POPx, [DI] AX MOV[]x, ;CODE
+CODE @ 1 chkPS, DI POPx, AX [DI] MOVx[], AX PUSHx, ;CODE
+CODE C! 2 chkPS, DI POPx, AX POPx, [DI] AX MOV[]r, ;CODE
+CODE C@ 1 chkPS,
+    DI POPx, AH AH XORrr, AL [DI] MOVr[], AX PUSHx, ;CODE
+CODE I [BP] 0 PUSH[w]+, ;CODE
+CODE I' [BP] -2 PUSH[w]+, ;CODE
+CODE J [BP] -4 PUSH[w]+, ;CODE
+CODE (resSP) SP PS_ADDR MOVxI, ;CODE
+CODE (resRS) BP RS_ADDR MOVxI, ;CODE

blk/818

@@ -1,5 +1,16 @@
-lblchkPS BSET ( CX -> expected size )
-    AX PS_ADDR MOVxI, AX SP SUBxx, 2 SUBAXI, ( CALL adjust )
-    AX CX CMPxx,
-    IFNC, ( we're good ) RETn, THEN,
-    ( underflow ) DI 0x06 MOVxm, JMPs, lblexec @ RPCs,
+CODE BYE BEGIN, JMPs, AGAIN, ;CODE
+CODE S= 2 chkPS,
+    SI POPx, DI POPx, CH CH XORrr, CL [SI] MOVr[],
+    CL [DI] CMPr[],
+    IFZ, ( same size? )
+        SI INCx, DI INCx, CLD, REPZ, CMPSB,
+    THEN,
+    PUSHZ,
+;CODE
+CODE CMP 2 chkPS,
+    BX POPx, AX POPx, CX CX XORxx, AX BX CMPxx,
+    IFNZ, ( < or > )
+        CX INCx, IFC, ( < ) CX DECx, CX DECx, THEN,
+    THEN,
+    CX PUSHx,
+;CODE

blk/821

@@ -1,9 +0,0 @@
-PC 3 - ORG @ 1+ ! ( main )
-    DX POPx, ( boot drive no ) 0x03 DL MOVmr,
-    SP PS_ADDR MOVxI, BP RS_ADDR MOVxI,
-    DI 0x08 MOVxm, ( LATEST )
-( HERE begins at CURRENT )
-    RAMSTART 0x4 ( HERE ) + DI MOVmx,
-    RAMSTART 0x2 ( CURRENT ) + DI MOVmx,
-    DI 0x04 ( BOOT ) MOVxm,
-    JMPn, lblexec @ RPCn, ( execute )

blk/822

@@ -1,16 +0,0 @@
-( native words )
-CODE EXECUTE 1 chkPS,
-    DI POPx, JMPn, lblexec @ RPCn,
-CODE >R 1 chkPS,
-    BP INCx, BP INCx, [BP] 0 POP[w]+,
-;CODE NOP, NOP, NOP,
-CODE R>
-    [BP] 0 PUSH[w]+, BP DECx, BP DECx,
-;CODE
-CODE 2R> 2 chkPS,
-    [BP] -2 PUSH[w]+, [BP] 0 PUSH[w]+, BP 4 SUBxi,
-;CODE
-CODE ROT ( a b c -- b c a ) 3 chkPS,
-    CX POPx, BX POPx, AX POPx,
-    BX PUSHx, CX PUSHx, AX PUSHx,
-;CODE

blk/823

@@ -1,12 +0,0 @@
-CODE DUP 1 chkPS, AX POPx, AX PUSHx, AX PUSHx, ;CODE
-CODE ?DUP 1 chkPS, AX POPx, AX AX ORxx, AX PUSHx,
-    IFNZ, AX PUSHx, THEN, ;CODE
-CODE DROP 1 chkPS, AX POPx, ;CODE
-CODE SWAP AX POPx, BX POPx, AX PUSHx, BX PUSHx, ;CODE
-CODE OVER ( a b -- a b a ) 2 chkPS,
-    DI SP MOVxx, AX [DI] 2 MOVx[]+, AX PUSHx, ;CODE
-CODE PICK
-    DI POPx, DI SHLx1, ( x2 )
-    CX DI MOVxx, CX 2 ADDxi, CALLn, lblchkPS @ RPCn,
-    DI SP ADDxx, DI [DI] MOVx[], DI PUSHx,
-;CODE

blk/824

@@ -1,16 +0,0 @@
-CODE (roll) ( "2 3 4 5 4 --> 2 4 5 5". See B311 )
-    CX POPx, CX 2 ADDxi, CALLn, lblchkPS @ RPCn, CX 2 SUBxi,
-    SI SP MOVxx, SI CX ADDxx,
-    DI SI MOVxx, DI 2 ADDxi, STD, REPZ, MOVSB,
-;CODE
-CODE 2DROP 2 chkPS, SP 4 ADDxi, ;CODE
-CODE 2DUP 2 chkPS,
-    AX POPx, BX POPx,
-    BX PUSHx, AX PUSHx, BX PUSHx, AX PUSHx,
-;CODE
-CODE S0 AX PS_ADDR MOVxI, AX PUSHx, ;CODE
-CODE 'S SP PUSHx, ;CODE
-CODE AND 2 chkPS,
-    AX POPx, BX POPx, AX BX ANDxx, AX PUSHx, ;CODE
-CODE OR 2 chkPS,
-    AX POPx, BX POPx, AX BX ORxx, AX PUSHx, ;CODE

blk/825

@@ -1,15 +0,0 @@
-CODE XOR 2 chkPS,
-    AX POPx, BX POPx, AX BX XORxx, AX PUSHx, ;CODE
-CODE NOT 1 chkPS,
-    AX POPx, AX AX ORxx,
-    IFNZ, AX -1 MOVxI, THEN, AX INCx, AX PUSHx,
-;CODE
-CODE + 2 chkPS,
-    AX POPx, BX POPx, AX BX ADDxx, AX PUSHx, ;CODE
-CODE - 2 chkPS,
-    BX POPx, AX POPx, AX BX SUBxx, AX PUSHx, ;CODE
-CODE * 2 chkPS,
-    AX POPx, BX POPx,
-    DX PUSHx, ( protect from MUL ) BX MULx, DX POPx,
-    AX PUSHx,
-;CODE

blk/826

@@ -1,16 +0,0 @@
-CODE /MOD 2 chkPS,
-    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
-CODE ! 2 chkPS, DI POPx, AX POPx, [DI] AX MOV[]x, ;CODE
-CODE @ 1 chkPS, DI POPx, AX [DI] MOVx[], AX PUSHx, ;CODE
-CODE C! 2 chkPS, DI POPx, AX POPx, [DI] AX MOV[]r, ;CODE
-CODE C@ 1 chkPS,
-    DI POPx, AH AH XORrr, AL [DI] MOVr[], AX PUSHx, ;CODE
-CODE I [BP] 0 PUSH[w]+, ;CODE
-CODE I' [BP] -2 PUSH[w]+, ;CODE
-CODE J [BP] -4 PUSH[w]+, ;CODE
-CODE (resSP) SP PS_ADDR MOVxI, ;CODE
-CODE (resRS) BP RS_ADDR MOVxI, ;CODE

blk/827

@@ -1,16 +0,0 @@
-CODE BYE BEGIN, JMPs, AGAIN, ;CODE
-CODE S= 2 chkPS,
-    SI POPx, DI POPx, CH CH XORrr, CL [SI] MOVr[],
-    CL [DI] CMPr[],
-    IFZ, ( same size? )
-        SI INCx, DI INCx, CLD, REPZ, CMPSB,
-    THEN,
-    PUSHZ,
-;CODE
-CODE CMP 2 chkPS,
-    BX POPx, AX POPx, CX CX XORxx, AX BX CMPxx,
-    IFNZ, ( < or > )
-        CX INCx, IFC, ( < ) CX DECx, CX DECx, THEN,
-    THEN,
-    CX PUSHx,
-;CODE

blk/830

@@ -0,0 +1,5 @@
+PC/AT recipe
+
+832 MBR bootloader             834 KEY/EMIT drivers
+836-838 BLK drivers            840 AT-XY drivers
+842 xcomp unit

blk/832

@@ -0,0 +1,12 @@
+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 0x800 MOVxI, DS AX MOVsx, ES AX MOVsx,
+SS AX MOVsx, DX PUSHx, ( will be popped by OS ) STI,
+AH 2 MOVri, DH 0 MOVri, CH 0 MOVri, CL 2 MOVri, AL 15 MOVri,
+BX 0 MOVxI, 0x13 INT, ( read sectors 2-15 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/834

@@ -0,0 +1,6 @@
+CODE (emit) 1 chkPS,
+    AX POPx, AH 0x0e MOVri, ( print char ) 0x10 INT,
+;CODE
+CODE (key)
+    AH AH XORrr, 0x16 INT, AH AH XORrr, AX PUSHx,
+;CODE

blk/836

@@ -0,0 +1,14 @@
+CODE 13H08H ( driveno -- cx dx )
+    DI POPx, DX PUSHx, ( protect ) DX DI MOVxx, AX 0x800 MOVxI,
+    ES PUSHs, DI DI XORxx, ES DI MOVsx,
+    0x13 INT, DI DX MOVxx, ES POPs, DX POPx, ( unprotect )
+    CX PUSHx, DI PUSHx,
+;CODE
+CODE 13H ( ax bx cx dx -- ax bx cx dx )
+    SI POPx, ( DX ) CX POPx, BX POPx, AX POPx,
+    DX PUSHx, ( protect ) DX SI MOVxx, DI DI XORxx,
+    0x13 INT, SI DX MOVxx, DX POPx, ( unprotect )
+    AX PUSHx, BX PUSHx, CX PUSHx, SI PUSHx,
+;CODE
+: FDSPT 0x70 RAM+ ;
+: FDHEADS 0x71 RAM+ ;

blk/837

@@ -0,0 +1,10 @@
+: _ ( AX BX sec )
+    ( AH=read sectors, AL=1 sector, BX=dest,
+      CH=trackno CL=secno DH=head DL=drive )
+    FDSPT C@ /MOD ( AX BX sec trk )
+    FDHEADS C@ /MOD ( AX BX sec head trk )
+    8 LSHIFT ROT OR 1+ ( AX BX head CX )
+    SWAP 8 LSHIFT 0x03 C@ ( boot drive ) OR ( AX BX CX DX )
+    13H 2DROP 2DROP
+;
+

blk/838

@@ -0,0 +1,14 @@
+: FD@
+    2 * 16 + ( blkfs starts at sector 16 )
+    0x0201 BLK( 2 PICK _
+    0x0201 BLK( 0x200 + ROT 1+ _ ;
+: FD!
+    2 * 16 + ( blkfs starts at sector 16 )
+    0x0301 BLK( 2 PICK _
+    0x0301 BLK( 0x200 + ROT 1+ _ ;
+: FD$
+    ( get number of sectors per track with command 08H. )
+    0x03 ( boot drive ) C@ 13H08H
+    8 RSHIFT 1+ FDHEADS C!
+    0x3f AND FDSPT C!
+;

blk/840

@@ -0,0 +1,8 @@
+: COLS 80 ; : LINES 25 ;
+CODE AT-XY ( x y )
+    ( DH=row DL=col BH=page )
+    AX POPx, BX POPx, DX PUSHx, ( protect )
+    DH AL MOVrr, DL BL MOVrr, BX BX XORxx, AH 2 MOVri,
+    0x10 INT, DX POPx, ( unprotect )
+;CODE
+

blk/842

@@ -0,0 +1,13 @@
+0xff00 CONSTANT RS_ADDR
+0xfffa CONSTANT PS_ADDR
+RS_ADDR 0x80 - CONSTANT RAMSTART
+750 LOAD  ( 8086 asm )
+262 LOAD  ( xcomp ) 270 LOAD  ( xcomp overrides )
+805 820 LOADR
+353 LOAD  ( xcomp core low )
+834 LOAD  ( KEY/EMIT drivers )
+836 838 LOADR  ( BLK drivers )
+840 LOAD  ( AT-XY drivers )
+380 LOAD  ( xcomp core high )
+(entry) _ ( Update LATEST ) PC ORG @ 8 + !
+," BLK$ FD$ ' FD@ BLK@* ! ' FD! BLK!* ! " EOT,

recipes/pcat/mbr.fs

@@ -1,4 +1,4 @@
 750 LOAD
-811 LOAD
+832 LOAD
 ORG @ 256 /MOD 2 PC! 2 PC!
 H@ 256 /MOD 2 PC! 2 PC!

recipes/pcat/xcomp.fs

@@ -1,68 +1,3 @@
-0xff00 CONSTANT RS_ADDR
-0xfffa CONSTANT PS_ADDR
-RS_ADDR 0x80 - CONSTANT RAMSTART
-750 LOAD  ( 8086 asm )
-262 LOAD  ( xcomp )
-270 LOAD  ( xcomp overrides )
-812 829 LOADR
-353 LOAD  ( xcomp core low )
-CODE (emit) 1 chkPS,
-    AX POPx, AH 0x0e MOVri, ( print char ) 0x10 INT,
-;CODE
-CODE (key)
-    AH AH XORrr, 0x16 INT, AH AH XORrr, AX PUSHx,
-;CODE
-CODE 13H08H ( driveno -- cx dx )
-    DI POPx, DX PUSHx, ( protect ) DX DI MOVxx, AX 0x800 MOVxI,
-    ES PUSHs, DI DI XORxx, ES DI MOVsx,
-    0x13 INT, DI DX MOVxx, ES POPs, DX POPx, ( unprotect )
-    CX PUSHx, DI PUSHx,
-;CODE
-CODE 13H ( ax bx cx dx -- ax bx cx dx )
-    SI POPx, ( DX ) CX POPx, BX POPx, AX POPx,
-    DX PUSHx, ( protect ) DX SI MOVxx, DI DI XORxx,
-    0x13 INT, SI DX MOVxx, DX POPx, ( unprotect )
-    AX PUSHx, BX PUSHx, CX PUSHx, SI PUSHx,
-;CODE
-: FDSPT 0x70 RAM+ ;
-: FDHEADS 0x71 RAM+ ;
-: _ ( AX BX sec )
-    ( AH=read sectors, AL=1 sector, BX=dest,
-      CH=trackno CL=secno DH=head DL=drive )
-    FDSPT C@ /MOD ( AX BX sec trk )
-    FDHEADS C@ /MOD ( AX BX sec head trk )
-    8 LSHIFT ROT OR 1+ ( AX BX head CX )
-    SWAP 8 LSHIFT 0x03 C@ ( boot drive ) OR ( AX BX CX DX )
-    13H 2DROP 2DROP
-;
-: FD@
-    2 * 16 + ( blkfs starts at sector 16 )
-    0x0201 BLK( 2 PICK _
-    0x0201 BLK( 0x200 + ROT 1+ _ ;
-: FD!
-    2 * 16 + ( blkfs starts at sector 16 )
-    0x0301 BLK( 2 PICK _
-    0x0301 BLK( 0x200 + ROT 1+ _ ;
-: FD$
-    ( get number of sectors per track with command 08H. )
-    0x03 ( boot drive ) C@ 13H08H
-    8 RSHIFT 1+ FDHEADS C!
-    0x3f AND FDSPT C!
-;
-: COLS 80 ; : LINES 25 ;
-CODE AT-XY ( x y )
-    ( DH=row DL=col BH=page )
-    AX POPx, BX POPx, DX PUSHx, ( protect )
-    DH AL MOVrr, DL BL MOVrr, BX BX XORxx, AH 2 MOVri,
-    0x10 INT, DX POPx, ( unprotect )
-;CODE
-380 LOAD  ( xcomp core high )
-(entry) _
-( Update LATEST )
-PC ORG @ 8 + !
-," BLK$ FD$ "
-," ' FD@ BLK@* ! "
-," ' FD! BLK!* ! "
-EOT,
+842 LOAD ( PC/AT xcomp )
 ORG @ 256 /MOD 2 PC! 2 PC!
 H@ 256 /MOD 2 PC! 2 PC!