RomWBW/Source/BPBIOS/wboot-ww.z80

;:::::::::::::::::::::::::::::::::::::::************************************
;	  Warm  Boot  Routine		***  Machine Dependant for Moves ***
;    - D-X Designs Pty Ltd P112 -	***  and custom load formatting  ***
;					************************************
; 1.0 - 12 Jun 96 - Initial Release for P112 from YASBEC.		HFB
;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

	CSEG

WBOOT:
	  IF  BANKED
	LD	A,(TPABNK)	; Get TPA Bank # in case currently in Bank
	CALL	SELMEM		; ..and make current
	LD	SP,USP		; Set stack in high memory
	  ELSE
	LD	SP,80H		; Use space below default buffer
	  ENDIF
	  
	  IF  FASTWB
	; Restore command processor from
	; cache in (SYSBNK):100H.  We assume that the
	; command processor lives in high memory.
	LD	A,(SYSBNK)	; Source bank is SYSBNK
	LD	C,A		; Put it in C
	LD	A,(TPABNK)	; Destination bank is TPABNK
	LD	B,A		; Put it in B
	CALL	HBX_XCOPY	; Set banks for extended copy
	LD	HL,100H		; Copy from start of cache in SYS
	LD	DE,(CPADR)	; .. to location of command processor in TPA
	LD	BC,(CPLEN)	; Length of command processor
	CALL	HBX_COPY	; Do it

WBOOTV:
	XOR	A	 	; Indicate "A" logged as Host Disk
	LD	(HSTDSK),A	; ..by showing Host Disk already logged
	  ELSE
	   IF  BANKED
	LD	SP,USP		; If banked, use stack in high common memory
	CALL	GOSYSB		; Disk routines are in banked memory
	   ELSE
	LD	SP,EXTSTK+32	; Place default stack up high
	   ENDIF

	LD	A,0FFH		; Insure the default drive is logged
	LD	(HSTDSK),A	; ..by unlogging the Host Disk
	LD	A,(SYSDRV)
	LD	C,A		; Select system disk
	LD	E,0		; Declare new mount
	CALL	SELDSK		; We're going to use the system disk
	LD	BC,0
	CALL	SETTRK		; Set track 0
	LD	BC,10H*256+1	; B sectors remaining, C first sector
	LD	DE,0		; DE beginning track

; Note that we begin by reading track 0, sector 1 since sector 0
;  contains the cold start loader, which is skipped in a warm start

	LD	HL,CPR		; Base of CP/M (initial load point)
LOAD1:	PUSH	DE		; Load a Sector, Save Current Track
	PUSH	BC		; Save sectors remaining and next sector
	PUSH	HL		; Save DMA address
	LD	(DMAADR),HL	; ..in deblocker
	LD	HL,(SEKDPH)
	LD	E,(HL)
	INC	HL
	LD	D,(HL)		; Get sector XLATE address
	CALL	SECTRN		; Skew sector as needed
	LD	(SEKSEC),HL	; Save Sector # directly in deblocker

; Drive = 0, track set, sector set, DMA address set

	CALL	READ
	OR	A		; Any errors?
	JR	NZ,WBOOT	; Retry the entire boot if an error occurs

; No error, move to next sector

	POP	HL		; Recall DMA address
	LD	DE,128		; DMA=DMA+128
	ADD	HL,DE		; New DMA address is in H,L
	POP	BC		; Recall NSECTS and current sector
	POP	DE		; Recall current track
	DEC	B		; Sectors=sectors-1
	JR	Z,GOZSYS	; Go to Z-System if all have been loaded

; More sectors remain to load, check for track change

	INC	C		; Increment sector count
	LD	A,(CPMSPT)	; Max sector +1
	CP	C		; Have we reached the end?
	JR	NZ,LOAD1	; If not

; End of current track, go to next track

	INC	DE		; Track=track+1
	LD	C,0		; First sector on next track

; Save register state, and set new track

	LD	(SEKTRK),DE	; Save track directly
	JR	LOAD1		; For another sector
	  ENDIF		;fastwb

; End load operation, set parameters & go to Z-System

GOZSYS:	LD	BC,80H		; Default DMA address is 80H
	CALL	SETDMA

	LD	A,0C3H		; C3 is a JMP instruction
	LD	(0),A		; For JMP to WBOOT
	LD	(5),A		; For JMP to BDOS
	LD	HL,BIOSJT+3	; Wboot entry point
	LD	(1),HL		; Set address field for JMP at 0
	LD	HL,(ENVADR)	; Get the pointer to the ENV
	LD	DE,43H		; Offset to high byte of Dos Start
	ADD	HL,DE
	LD	D,(HL)		; Load Dos start
	DEC	HL
	LD	E,(HL)
	EX	DE,HL		; Put Dos in HL
	LD	BC,6		; .offset to Entry
	ADD	HL,BC
	LD	(6),HL		; ..and set Address field of jump at 5 to BDOS
	EX	DE,HL
	DEC	HL		; Back down to CCP entry
	DEC	HL
	LD	D,(HL)		; Get the vector
	DEC	HL
	LD	E,(HL)
	PUSH	DE		; Save CCP entry address

	  IF  BANKED
	; Copy vectors from TPA page zero to SYS page zero
	LD	BC,(TPABNK)	; C := TPABNK, B := SYSBNK
	CALL	XMOVE		; Set source/dest banks for copy
	LD	HL,0		; Source address is zero
	LD	DE,0		; Destination address is zero
	LD	BC,40H		; Copy 40H bytes
	CALL	MOVE		; Do it
	LD	A,(TPABNK)	; Set all Bank regs to TPA
	LD	(DMABNK),A

	CALL	SELMEM		; Insure TPA in context (also set USRBNK)
	XOR	A
	LD	(BIOSTK),A	; Init bank switcher
	  ENDIF
	LD	A,(4)		; Get current disk number
	LD	C,A		; Send to the CCP
;	EI			; Enable the interrupt system
;	EX	DE,HL		; ..put destination in HL
	POP	HL		; Restore CCP entry address
	
	JP	(HL)		; Go to Z-System for further processing

	  IF  [Z3 AND HAVIOP]
; Aux Jump Table so IOP's can find routines.  After Cold Boot, the
; address of this table is placed in BIOSJT+1.

IOPRET:	JP	CONST
	JP	CONIN
	JP	CONOUT
	JP	LIST
	JP	AUXOUT
	JP	AUXIN
	JP	LISTST
	  ENDIF

	DSEG			; Put the following areas in Data Segment

; Command processor address and length used when saving
; and restoring cached copy.
	  IF  FASTWB
CPADR	DEFS	2		; Command processor address
CPLEN	DEFS	2		; Command processor length
	  ENDIF		;fastwb
;========================= End of WBOOT ============================