pcat: use boot drive no passed to bootloader through DL

instead of hardcoded drive 0.

blk/760

@@ -1,7 +1,10 @@
 : MOVri, SWAP 0xb0 OR A, A, ;
 : MOVxI, SWAP 0xb8 OR A, A,, ;
-: MOVsx, 0x8e A, SWAP 3 LSHIFT OR 0xc0 OR A, ;
-: MOVxm, 0x8b A, SWAP 3 LSHIFT 0x6 OR A, A,, ;
+: MOVsx, 0x8e A, SWAP <<3 OR 0xc0 OR A, ;
+: MOVrm, 0x8a A, SWAP <<3 0x6 OR A, A,, ;
+: MOVxm, 0x8b A, SWAP <<3 0x6 OR A, A,, ;
+: MOVmr, 0x88 A, <<3 0x6 OR A, A,, ;
+: MOVmx, 0x89 A, <<3 0x6 OR A, A,, ;
 : SUBxi, 0x83 A, SWAP 0xe8 OR A, A, ;
 : ADDxi, 0x83 A, SWAP 0xc0 OR A, A, ;
 : JMPr, 0xff A, 7 AND 0xe0 OR A, ;

blk/811

@@ -3,9 +3,9 @@ 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, STI,
-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 )
+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,

blk/812

@@ -1,11 +1,11 @@
 VARIABLE lblexec VARIABLE lblnext
 H@ ORG !
-JMPn, 0 A,, ( 00, main ) 0 A, ( unused ) 0 A,, ( 04, BOOT )
+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, 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,, ( 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 )

blk/821

@@ -1,9 +1,9 @@
 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 )
-    BX RAMSTART MOVxI,
-    [BX] 0x04 ( HERE ) DI MOV[]+x,
-    [BX] 0x02 ( CURRENT ) DI MOV[]+x,
+    RAMSTART 0x4 ( HERE ) + DI MOVmx,
+    RAMSTART 0x2 ( CURRENT ) + DI MOVmx,
     DI 0x04 ( BOOT ) MOVxm,
     JMPn, lblexec @ RPCn, ( execute )

recipes/pcat/Makefile

@@ -13,13 +13,14 @@ os.bin: xcomp.fs $(STAGE)
 
 disk.bin: mbr.bin os.bin
 	cat mbr.bin os.bin > $@
+	dd if=$(EDIR)/blkfs of=$@ bs=512 seek=16
 
 $(STAGE):
 	$(MAKE) -C $(EDIR) stage
 
 .PHONY: emul
 emul: $(TARGET)
-	qemu-system-i386 -fda $(TARGET)
+	qemu-system-i386 -drive file=$(TARGET),if=floppy,format=raw
 
 .PHONY: clean
 clean:

recipes/pcat/xcomp.fs

@@ -10,11 +10,46 @@ 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
+    AH AH XORrr, 0x16 INT, AH AH XORrr, AX PUSHx,
+;CODE
+CODE 13H08H ( driveno -- cx )
+    DI POPx, DX PUSHx, ( protect ) DX DI MOVxx, AX 0x800 MOVxI,
+    DI DI XORxx, ES DI MOVsx,
+    0x13 INT, DX POPx, ( unprotect ) CX PUSHx,
+    DI 0x800 MOVxI, ES DI MOVsx,
+;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+ ;
+: _ ( dest secno )
+    ( AH=read sectors, AL=1 sector, BX=dest,
+      CH=trackno CL=secno DH=head DL=drive )
+    0x0201 ROT ROT ( AX BX sec )
+    FDSPT @ /MOD ( AX BX sec trk )
+    2 /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 )
+    BLK( OVER _ BLK( 0x200 + SWAP 1+ _ ;
+: FD! DROP ;
+: FD$
+    ( get number of sectors per track with command 08H. )
+    0x03 ( boot drive ) C@ 13H08H 0x3f AND FDSPT !
+;
 380 LOAD  ( xcomp core high )
 (entry) _
 ( Update LATEST )
 PC ORG @ 8 + !
+," BLK$ FD$ "
+," ' FD@ BLK@* ! "
+," ' FD! BLK!* ! "
 EOT,
 ORG @ 256 /MOD 2 PC! 2 PC!
 H@ 256 /MOD 2 PC! 2 PC!