mirror of https://github.com/wwarthen/RomWBW.git
doug
13 years ago
1 changed files with 112 additions and 0 deletions
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; btromwbw.inc 2/17/2013 dwg - boot up CP/M, RomWBW Style ; |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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; Unlike the Monahan style of booting, the RomWBW loading ; |
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; is performed by reading in the metadata sector and using ; |
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; the three words at the end of the sector to determine the ; |
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; loading address and starting location. ; |
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; |
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;-------------- BOOT UP CPM FROM HARD DISK ON S100COMPUTERS IDR BOARD ---------------- |
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;BOOT UP THE 8255/IDE Board HARD DISK/Flash Memory Card |
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;NOTE CODE IS ALL HERE IN CASE A 2716 IS USED |
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HBOOTWBW: |
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POP HL ;CLEAN UP STACK |
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CALL INITILIZE_IDE_BOARD ;Initilze the 8255 and drive (again just in case) |
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LD D,11100000B ;Data for IDE SDH reg (512bytes, LBA mode,single drive) |
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LD E,REGshd ;00001110,(0EH) CS0,A2,A1, |
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CALL IDEwr8D ;Write byte to select the MASTER device |
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LD B,0FFH ;Delay time to allow a Hard Disk to get up to speed |
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WaitInitX: |
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LD E,REGstatus ;Get status after initilization |
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CALL IDErd8D ;Check Status (info in [D]) |
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BIT 7,D |
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JR Z,SECREAD ;Zero, so all is OK to write to drive |
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;Delay to allow drive to get up to speed |
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PUSH BC |
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LD BC,0FFFFH |
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DXLAY2X: LD D,2 ;May need to adjust delay time to allow cold drive to |
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DXLAY1X: DEC D ;to speed |
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JR NZ,DXLAY1X |
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DEC BC |
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LD A,C |
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OR B |
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JR NZ,DXLAY2X |
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POP BC |
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DJNZ WaitInitX ;If after 0FFH, 0FEH, 0FDH... 0, then drive initilization problem |
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IDErrorX: |
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LD HL,DRIVE_NR_ERR ;Drive not ready |
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JP ABORT_ERR_MSG |
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SECREADX: ;Note CPMLDR will ALWAYS be on TRK 0,SEC 1,Head 0 |
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CALL IDEwaitnotbusy ;Make sure drive is ready |
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JR C,IDError ;NC if ready |
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LD D,1 ;Load track 0,sec 1, head 0 |
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LD E,REGsector ;Send info to drive |
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CALL IDEwr8D |
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LD D,0 ;Send Low TRK# |
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LD E,REGcyLSB |
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CALL IDEwr8D |
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LD D,0 ;Send High TRK# |
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LD E,REGcyMSB |
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CALL IDEwr8D |
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LD D,SEC_COUNT ;Count of CPM sectors we wish to read |
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LD E,REGcnt |
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CALL IDEwr8D |
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LD D,CMDread ;Send read CMD |
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LD E,REGCMD |
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CALL IDEwr8D ;Send sec read CMD to drive. |
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CALL IDEwdrq ;Wait until it's got the data |
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LD HL,CPM_ADDRESS ;DMA address where the CPMLDR resides in RAM |
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LD B,0 ;256X2 bytes |
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LD C,SEC_COUNT ;Count of sectors X 512 |
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MoreRD16X: |
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LD A,REGdata ;REG regsiter address |
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OUT (IDECport),A |
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OR IDErdline ;08H+40H, Pulse RD line |
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OUT (IDECport),A |
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IN A,(IDEAport) ;read the LOWER byte |
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LD (HL),A |
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INC HL |
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IN A,(IDEBport) ;read the UPPER byte |
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LD (HL),A |
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INC HL |
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LD A,REGdata ;Deassert RD line |
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OUT (IDECport),A |
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DJNZ MoreRD16X |
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DEC C |
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JR NZ,MoreRD16X |
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LD E,REGstatus ;Check the R/W status when done |
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CALL IDErd8D |
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BIT 0,D |
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JR NZ,IDEerr1 ;Z if no errors |
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LD HL,STARTCPM |
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LD A,(HL) |
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CP 31H ;EXPECT TO HAVE 31H @80H IE. LD SP,80H |
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JP Z,STARTCPM ;AS THE FIRST INSTRUCTION. IF OK JP to 100H in RAM |
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JP ERR_LD1 ;Boot Sector Data incorrect |
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IDEerr1X: |
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LD HL,IDE_RW_ERROR ;Drive R/W Error |
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JP ABORT_ERR_MSG |
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;;;;;;;;;;;;;;;;;;;;;; |
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; eof - btromwbw.inc ; |
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;;;;;;;;;;;;;;;;;;;;;; |
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