--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/level1/modules/boot_dw.asm	Mon Jul 30 19:35:05 2012 -0500
@@ -0,0 +1,143 @@
+********************************************************************
+* Boot - DriveWire 3 Boot Module
+*
+* $Id$
+*
+* Edt/Rev  YYYY/MM/DD  Modified by
+* Comment
+* ------------------------------------------------------------------
+*   1      2008/02/09  Boisy G. Pitre
+* Created.
+
+               NAM       Boot
+               TTL       DriveWire Boot Module
+
+               IFP1      
+               USE       defsfile
+               USE       drivewire.d
+               ENDC      
+
+tylg           SET       Systm+Objct
+atrv           SET       ReEnt+rev
+rev            SET       0
+edition        SET       1
+
+               MOD       eom,name,tylg,atrv,start,size
+
+* on-stack buffer to use
+               ORG       0
+seglist        RMB       2                   pointer to segment list
+blockloc       RMB       2                   pointer to memory requested
+blockimg       RMB       2                   duplicate of the above
+bootloc        RMB       3                   sector pointer; not byte pointer
+bootsize       RMB       2                   size in bytes
+LSN0Ptr        RMB       2                   LSN0 pointer
+size           EQU       .
+
+name           EQU       *
+               FCS       /Boot/
+               FCB       edition
+
+
+* Common booter-required defines
+LSN24BIT       EQU       1
+FLOPPY         EQU       0
+
+
+               USE       boot_common.asm
+
+
+************************************************************
+************************************************************
+*              Hardware-Specific Booter Area               *
+************************************************************
+************************************************************                   
+
+* HWInit - Initialize the device
+*   Entry: Y = hardware address
+*   Exit:  Carry Clear = OK, Set = Error
+*          B = error (Carry Set)
+HWInit                   
+* Set up DDR for side B
+*               ldx       #PIA1Base           get base address of PIA
+*               ldb       3,x
+*               andb      #%11111011
+*               stb       3,x
+*               lda       #%11111010
+*               sta       2,x
+*               orb       #%00000100
+*               stb       3,x
+
+* Set up DDR for side A
+*               ldb       1,x
+*               andb      #%11111011
+*               stb       1,x                 $FF20 is now Data Direction Register
+*               lda       #%11111110          data direction bits (1=out, 0=in)
+*               sta       ,x                  tell HW
+*               orb       #%00000100          reset $FF20 to I/O register
+*               stb       1,x                 $FF20 is now Data Direction Register
+HWTerm         clrb      
+               rts       
+
+
+* HWRead - Read a 256 byte sector from the device
+*   Entry: Y = hardware address
+*          B = bits 23-16 of LSN
+*          X = bits 15-0  of LSN
+* 		   blockloc,u = ptr to 256 byte sector
+*   Exit:  X = ptr to data (i.e. ptr in blockloc,u)
+HWRead         
+               pshs      cc,d,x
+* Send out op code and 3 byte LSN
+               lda       #OP_READEX           load A with READ opcode
+Read2          ldb       WhichDrv,pcr
+               std       ,s
+               leax      ,s
+               ldy       #5
+               lbsr      DWWrite              send it to server
+* Get 256 bytes of sector data
+               ldx       blockloc,u
+               ldy       #256
+               bsr       DWRead               read bytes from server
+               bcs       ReadEr               branch if framing error
+               bne       ReadEr2
+               
+* Send two byte checksum
+               pshs      y
+	 		      leax      ,s
+			      ldy       #2
+			      lbsr      DWWrite 
+                              ldy       #1
+			      bsr       DWRead 
+			      leas      2,s
+     			   bcs       ReadEx
+                           bne      ReadEr2
+			      ldb       ,s
+			      beq       ReadEx
+			      cmpb      #E_CRC
+			      bne       ReadEr
+               lda       #OP_REREADEX
+               bra       Read2
+ReadEx         EQU       *
+               leas      5,s                 eat stack
+               ldx       blockloc,u
+               clrb      
+               rts
+ReadEr2        ldb       #E$Read
+ReadEr
+               leas      5,s                 eat stack
+               orcc      #Carry
+               rts
+
+               USE       dwread.asm
+               USE       dwwrite.asm
+
+               IFGT      Level-1
+Pad            FILL      $39,$1D0-3-2-1-*
+               ENDC      
+
+Address        FDB       $0000
+WhichDrv       FCB       $00
+               EMOD      
+eom            EQU       *
+               END