;[BEGIN]
;//MODULE: DOS_FM
;//CREATE: 19-05-1998	AUTHOR:	Denis Parinov
;//UPDATE: 24-10-1999	DNS	Restore	module
;---------------------------------------------------------------
;Rev	Date	   Name	Description
;---------------------------------------------------------------
;R01	16-11-1999 DNS  ERROR READING FAT CHAIN
;---------------------------------------------------------------

;FMS	DB	FMCOUNT

;ACCESS	MODE:
;	00 - READ/WRITE
;	01 - READ
;	02 - WRITE
;FM_BUF:
;File Manipulator (FM)
        ; BYTE	'.       '      ;+00 NAME
        ; BYTE	'   '           ;+08 EXT
        ; BYTE    #10           ;+11 ATTRIBUT
        ; BYTE    0             ;+12 RESERVED;  !TODO следующий кластер для чтения
        ; BYTE    0             ;+13 RESERVED;  !TODO следующий кластер для записи
        ; BLOCK	8,0             ;+14 RESERVED
        ; WORD	#0000           ;+22 TIME
        ; WORD	#0000           ;+24 DATE
        ; WORD	#0000           ;+26 START CLUSTER
        ; DWORD	#0000           ;+28 SIZE FILE
        ; DWORD	#0000           ;+32 FILE POSITION (FP)
        ; WORD	#0000           ;+36 DIRECTORY CLUSTER
        ; WORD	#0000           ;+38 HANDLE NUMBER
        ; BYTE	#00             ;+40 DRIVE OR CURRENT
        ; BYTE	#00             ;+41 ACCESS MODE
        ; BYTE	#00             ;+42 TASK
        ; BYTE	#00             ;+43 EMPTY
/*
;!TEST
FM_BUF: _sFM
.Size   EQU     _sFM
	BLOCK	(FMCOUNT-1)*FM_BUF.Size, 0
*/

; на выходе без ошибок IY указывает на файловый манипулятор
 MACRO _mFM_FIND
	CP	FMCOUNT
	JR	NC,ABS_FM
	PUSH	DE

	LD	IY,CORE_BUFFERS.FM_BUF
	LD	DE,CORE_BUFFERS.FM_BUF.Size
	AND	A
	JR	Z,.endLoop
.loop:	ADD	IY,DE
	DEC	A
	JR	NZ,.loop
.endLoop:
	POP	DE
	;   A=0
	OR	(IY)	;+00 NAME
 ENDM
////////////////////////////////////////////////////////////////////////

SET_FM:	_mFM_FIND
	LD	A,DSS_Error.sys.NO_ERROR
	RET	NZ
ABS_FM	LD	A,DSS_Error.sys.INVALID_HANDLE
	SCF 
	RET 


RES_FM:	_mFM_FIND
	LD	A,DSS_Error.sys.INVALID_HANDLE
	;EXX 
	SCF 
	RET	Z
	XOR	A
	LD	(IY+0),A
	RET 
;
GET_FM:	LD	B,FMCOUNT
	LD	C,#FF
	LD	IY,CORE_BUFFERS.FM_BUF - CORE_BUFFERS.FM_BUF.Size
	LD	DE,CORE_BUFFERS.FM_BUF.Size
.loop:	ADD	IY,DE
	INC	C
	LD	A,(IY+0)
	OR	A
	RET	Z
	DJNZ	.loop
	LD	A,DSS_Error.sys.NO_HANDLES
	SCF 
	RET 
/*
	;!TEST	CHECK LOCKING 10/11/2023
GET_FM: LD	IY,0
	LD	(.freeHandle),IY
	;
	LD	B,FMCOUNT
	LD	C,#FF
	LD	IY,CORE_BUFFERS.FM_BUF - CORE_BUFFERS.FM_BUF.Size
	LD	DE,CORE_BUFFERS.FM_BUF.Size
.loop:	ADD	IY,DE
	INC	C
	; CHECK LOCKING
	 
	;
.cont:	LD	A,(IY+0)
	OR	A
	RET	Z
	DJNZ	.loop
	LD	A,DSS_Error.sys.NO_HANDLES
	SCF 
	RET 
*/


; HL:IX	- OFFSET POINTER
;     A	- FILE MANIPULATOR
MOVE_FP:
	CALL	SET_FM
	RET	C
	INC	B
	DEC	B
	JR	Z,.F_start
	DEC	B
	JR	Z,.F_current
	DEC	B
	JR	Z,.B_end
	LD	A,DSS_Error.sys.INVALID_FUNCTION
	SCF 
	RET 
;from Start File
.F_start:
        ;   B=0
        LD      C,B
        LD      D,B
        LD      E,B
	JP	.DO
;from End File
.B_end:	LD	C,(IY+_sFM.F_SIZE)
	LD	B,(IY+_sFM.F_SIZE+1)
	LD	E,(IY+_sFM.F_SIZE+2)
	LD	D,(IY+_sFM.F_SIZE+3)
	JP	.DO
;from Current Position
.F_current:
	LD	C,(IY+_sFM.F_POSITION)
	LD	B,(IY+_sFM.F_POSITION+1)
	LD	E,(IY+_sFM.F_POSITION+2)
	LD	D,(IY+_sFM.F_POSITION+3)
.DO:	ADD	IX,BC
	ADC	HL,DE
	LD	D,XH
	LD	E,XL
	LD	(IY+_sFM.F_POSITION),E
	LD	(IY+_sFM.F_POSITION+1),D
	LD	(IY+_sFM.F_POSITION+2),L
	LD	(IY+_sFM.F_POSITION+3),H
	XOR	A
	RET 

;FP COMPARE
; CY - FILE POINTER > SIZE
; NC - FILE POINTER < SIZE
MOVE_CP:
	LD	L,(IY+_sFM.F_SIZE)
	LD	H,(IY+_sFM.F_SIZE+1)
	LD	E,(IY+_sFM.F_POSITION)
	LD	D,(IY+_sFM.F_POSITION+1)
	AND	A
	SBC	HL,DE
	LD	L,(IY+_sFM.F_SIZE+2)
	LD	H,(IY+_sFM.F_SIZE+3)
	LD	E,(IY+_sFM.F_POSITION+2)
	LD	D,(IY+_sFM.F_POSITION+3)
	SBC	HL,DE
	RET 


;	HL:DE /	C => DE:IX HL-OSTATOK (DE:BC.HL). Легко переделать под  HL:DE / A => HL:DE.A
DIV_for_SPC:
	LD	A,C
	DEC	A
	JR	Z,.exit
;
	AND	E
	LD	B,A	; остаток
	LD	A,C
	RRCA
;
.loop:	SRL H	: RR L 
	RR D	: RR E
	RRCA
	JP	NC,.loop
	LD	A,B
;
.exit:	LD	XH,D
	LD	XL,E
	EX	DE,HL
	LD	H,0
	LD	L,A
	RET
; DIV32:	LD	A,#FF
; 	LD	B,E
; .loop:	SRL	C
; 	JR	C,.exitLoop
; 	SRL H : RR L : RR D : RR E : SLA A
; 	JP	.loop
; .exitLoop:
; 	CPL
; 	AND	B
; 	LD	XH,D
; 	LD	XL,E
; 	EX	DE,HL
; 	LD	H,0
; 	LD	L,A
; 	RET
/*
	DEFINE NEW_DIV 1

DIV32:	LD	XH,D
	LD	XL,E

	IFN NEW_DIV
	EX	DE,HL
	LD	HL,0
	LD	A,#20
DIV001:	ADD	IX,IX
	EX	DE,HL
	ADC	HL,HL
	EX	DE,HL
	ADC	HL,HL
	SBC	HL,BC
	JR	NC,DIV002
	ADD	HL,BC
	DEC	A
	JR	NZ,DIV001
	RET 
DIV002:	INC	IX
	DEC	A
	JR	NZ,DIV001
	RET
	ELSE 


div32_16:
;HLIX/BC -> HLIX remainder DE
;174+4*div32_16_sub8
;min: 2186cc
;max: 2794cc
;avg: 2466cc
;61 bytes
  ex de,hl   ; 4

; Negate BC to allow add instead of sbc
  xor a      ; 4
; Need to set HL to 0 anyways, so save 2cc and a byte
  ld h,a     ; 4
  ld l,a     ; 4
  sub c      ; 4
  ld c,a     ; 4
  sbc a,a    ; 4
  sub b      ; 4
  ld b,a     ; 4


  ld a,d              ; 4
  call div32_16_sub8  ; 17
  rla                 ; 4
  ld d,a              ; 4

  ld a,e              ; 4
  call div32_16_sub8  ; 17
  rla                 ; 4
  ld e,a              ; 4

  ld a,ixh            ; 8
  call div32_16_sub8  ; 17
  rla                 ; 4
  ld ixh,a            ; 8

  ld a,ixl            ; 8
  call div32_16_sub8  ; 17
  rla                 ; 4
  ld ixl,a            ; 8

  ;ex de,hl   ; 4
  ret        ; 10

div32_16_sub8:
;119+8*div32_16_sub
;min: 503cc
;max: 655cc
;avg: 573cc
  call 1F
1:
;17+2(17+2(div32_16_sub)))
  call 1F
1:
;17+2(div32_16_sub)
  call div32_16_sub
div32_16_sub:
;48+{8,0+{0,19}}
;min: 48cc
;max: 67cc
;avg: 56.75cc
  rla        ; 4
  adc hl,hl  ; 15
  jr c,1F    ;12/7
  add hl,bc  ; 11
  ret c      ;11/5
  sbc hl,bc  ; 15
  ret        ; 10
1:
  add hl,bc  ; 11
  scf        ; 4
  ret        ; 10

	ENDIF
*/
;