mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-01 19:20:56 +11:00
89 lines
2.7 KiB
Forth
89 lines
2.7 KiB
Forth
( ----- 600 )
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PC/AT recipe
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602 MBR bootloader 604 KEY/EMIT drivers
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606-608 BLK drivers 610 AT-XY drivers
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612 xcomp unit
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( ----- 602 )
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H@ ORG ! 0x7c00 BIN( ! ( BIOS loads boot bin at 0x7c00 )
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JMPs, L1 FWRs ( start )
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ORG @ 0x25 + HERE ! ( bypass BPB )
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L1 FSET ( start )
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CLI, CLD, AX 0x800 MOVxI, DS AX MOVsx, ES AX MOVsx,
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SS AX MOVsx, DX PUSHx, ( will be popped by OS ) STI,
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AH 2 MOVri, DH 0 MOVri, CH 0 MOVri, CL 2 MOVri, AL 15 MOVri,
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BX 0 MOVxI, 0x13 INT, ( read sectors 2-15 of boot floppy )
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( TODO: reading 12 sectors like this probably doesn't work
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on real vintage PC/AT with floppy. Make this more robust. )
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0x800 0 JMPf,
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ORG @ 0x1fe + HERE ! 0x55 C, 0xaa C,
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( ----- 604 )
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CODE (emit) 1 chkPS,
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AX POPx, AH 0x0e MOVri, ( print char ) 0x10 INT,
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;CODE
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CODE (key?)
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AH AH XORrr, 0x16 INT, AH AH XORrr, AX PUSHx, AX PUSHx,
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;CODE
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( ----- 606 )
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CODE 13H08H ( driveno -- cx dx )
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DI POPx, DX PUSHx, ( protect ) DX DI MOVxx, AX 0x800 MOVxI,
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ES PUSHs, DI DI XORxx, ES DI MOVsx,
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0x13 INT, DI DX MOVxx, ES POPs, DX POPx, ( unprotect )
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CX PUSHx, DI PUSHx,
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;CODE
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CODE 13H ( ax bx cx dx -- ax bx cx dx )
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SI POPx, ( DX ) CX POPx, BX POPx, AX POPx,
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DX PUSHx, ( protect ) DX SI MOVxx, DI DI XORxx,
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0x13 INT, SI DX MOVxx, DX POPx, ( unprotect )
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AX PUSHx, BX PUSHx, CX PUSHx, SI PUSHx,
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;CODE
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( ----- 607 )
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: FDSPT 0x70 RAM+ ;
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: FDHEADS 0x71 RAM+ ;
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: _ ( AX BX sec )
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( AH=read sectors, AL=1 sector, BX=dest,
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CH=trackno CL=secno DH=head DL=drive )
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FDSPT C@ /MOD ( AX BX sec trk )
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FDHEADS C@ /MOD ( AX BX sec head trk )
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8 LSHIFT ROT OR 1+ ( AX BX head CX )
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SWAP 8 LSHIFT 0x03 C@ ( boot drive ) OR ( AX BX CX DX )
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13H 2DROP 2DROP
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;
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( ----- 608 )
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: FD@
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2 * 16 + ( blkfs starts at sector 16 )
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0x0201 BLK( 2 PICK _
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0x0201 BLK( 0x200 + ROT 1+ _ ;
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: FD!
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2 * 16 + ( blkfs starts at sector 16 )
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0x0301 BLK( 2 PICK _
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0x0301 BLK( 0x200 + ROT 1+ _ ;
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: FD$
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( get number of sectors per track with command 08H. )
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0x03 ( boot drive ) C@ 13H08H
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8 RSHIFT 1+ FDHEADS C!
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0x3f AND FDSPT C!
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;
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( ----- 610 )
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: COLS 80 ; : LINES 25 ;
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CODE AT-XY ( x y )
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( DH=row DL=col BH=page )
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AX POPx, BX POPx, DX PUSHx, ( protect )
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DH AL MOVrr, DL BL MOVrr, BX BX XORxx, AH 2 MOVri,
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0x10 INT, DX POPx, ( unprotect )
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;CODE
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( ----- 612 )
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0xff00 CONSTANT RS_ADDR
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0xfffa CONSTANT PS_ADDR
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RS_ADDR 0xa0 - CONSTANT SYSVARS
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30 LOAD ( 8086 asm )
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262 LOAD ( xcomp ) 270 LOAD ( xcomp overrides )
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445 461 LOADR ( 8086 boot code )
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353 LOAD ( xcomp core low )
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604 LOAD ( KEY/EMIT drivers )
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606 608 LOADR ( BLK drivers )
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610 LOAD ( AT-XY drivers )
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390 LOAD ( xcomp core high )
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(entry) _ ( Update LATEST ) PC ORG @ 8 + !
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," BLK$ FD$ ' FD@ ' BLK@* **! ' FD! ' BLK!* **! " EOT,
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