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collapseos/recipes/pcat/xcomp.fs
Virgil Dupras 515890717f pcat: use heads count from 13H08H
On real hardware, there aren't always 2 heads...
2020-06-22 05:59:26 -04:00

60 lines
1.6 KiB
Forth

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,
DI DI XORxx, ES DI MOVsx,
0x13 INT, DI DX MOVxx, DX POPx, ( unprotect )
CX PUSHx, DI 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+ ;
: FDHEADS 0x71 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 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 )
BLK( OVER _ BLK( 0x200 + SWAP 1+ _ ;
: FD! DROP ;
: FD$
( get number of sectors per track with command 08H. )
0x03 ( boot drive ) C@ 13H08H
8 RSHIFT 1+ FDHEADS C!
0x3f AND FDSPT C!
;
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!