; Maciej 'YTM/Elysium' Witkowiak <ytm@elysium.pl>
; 06,20.12.2002
- .include "zeropage.inc"
+ .include "zeropage.inc"
- .include "em-kernel.inc"
- .include "em-error.inc"
+ .include "em-kernel.inc"
+ .include "em-error.inc"
.macpack generic
; Driver signature
.byte $65, $6d, $64 ; "emd"
- .byte EMD_API_VERSION ; EM API version number
+ .byte EMD_API_VERSION ; EM API version number
; Jump table.
.word DEINSTALL
.word PAGECOUNT
.word MAP
- .word USE
+ .word USE
.word COMMIT
- .word COPYFROM
+ .word COPYFROM
.word COPYTO
; ------------------------------------------------------------------------
; Constants
-VDC_ADDR_REG = $D600 ; VDC address
-VDC_DATA_REG = $D601 ; VDC data
+VDC_ADDR_REG = $D600 ; VDC address
+VDC_DATA_REG = $D601 ; VDC data
-VDC_DATA_HI = 18 ; used registers
-VDC_DATA_LO = 19
-VDC_CSET = 28
-VDC_DATA = 31
+VDC_DATA_HI = 18 ; used registers
+VDC_DATA_LO = 19
+VDC_CSET = 28
+VDC_DATA = 31
; ------------------------------------------------------------------------
; Data.
.data
-pagecount: .word 64 ; $0000-$3fff as 16k default
-curpage: .word $ffff ; currently mapped-in page (invalid)
+pagecount: .word 64 ; $0000-$3fff as 16k default
+curpage: .word $ffff ; currently mapped-in page (invalid)
.bss
-window: .res 256 ; memory window
+window: .res 256 ; memory window
.code
;
INSTALL:
- ; do test for VDC presence here???
-
- ldx #VDC_CSET ; determine size of RAM...
- jsr vdcgetreg
- sta tmp1
- ora #%00010000
- jsr vdcputreg ; turn on 64k
-
- jsr settestadr1 ; save original value of test byte
- jsr vdcgetbyte
- sta tmp2
-
- lda #$55 ; write $55 here
- ldy #ptr1
- jsr test64k ; read it here and there
- lda #$aa ; write $aa here
- ldy #ptr2
- jsr test64k ; read it here and there
-
- jsr settestadr1
- lda tmp2
- jsr vdcputbyte ; restore original value of test byte
-
- lda ptr1 ; do bytes match?
- cmp ptr1+1
- bne @have64k
- lda ptr2
- cmp ptr2+1
- bne @have64k
-
- ldx #VDC_CSET
- lda tmp1
- jsr vdcputreg ; restore 16/64k flag
- jmp @endok ; and leave default values for 16k
+ ; do test for VDC presence here???
+
+ ldx #VDC_CSET ; determine size of RAM...
+ jsr vdcgetreg
+ sta tmp1
+ ora #%00010000
+ jsr vdcputreg ; turn on 64k
+
+ jsr settestadr1 ; save original value of test byte
+ jsr vdcgetbyte
+ sta tmp2
+
+ lda #$55 ; write $55 here
+ ldy #ptr1
+ jsr test64k ; read it here and there
+ lda #$aa ; write $aa here
+ ldy #ptr2
+ jsr test64k ; read it here and there
+
+ jsr settestadr1
+ lda tmp2
+ jsr vdcputbyte ; restore original value of test byte
+
+ lda ptr1 ; do bytes match?
+ cmp ptr1+1
+ bne @have64k
+ lda ptr2
+ cmp ptr2+1
+ bne @have64k
+
+ ldx #VDC_CSET
+ lda tmp1
+ jsr vdcputreg ; restore 16/64k flag
+ jmp @endok ; and leave default values for 16k
@have64k:
- lda #<256
- ldx #>256
- sta pagecount
- stx pagecount+1
+ lda #<256
+ ldx #>256
+ sta pagecount
+ stx pagecount+1
@endok:
- lda #<EM_ERR_OK
+ lda #<EM_ERR_OK
ldx #>EM_ERR_OK
rts
test64k:
- sta tmp1
- sty ptr3
- lda #0
- sta ptr3+1
- jsr settestadr1
- lda tmp1
- jsr vdcputbyte ; write $55
- jsr settestadr1
- jsr vdcgetbyte ; read here
- pha
- jsr settestadr2
- jsr vdcgetbyte ; and there
- ldy #1
- sta (ptr3),y
- pla
- dey
- sta (ptr3),y
- rts
+ sta tmp1
+ sty ptr3
+ lda #0
+ sta ptr3+1
+ jsr settestadr1
+ lda tmp1
+ jsr vdcputbyte ; write $55
+ jsr settestadr1
+ jsr vdcgetbyte ; read here
+ pha
+ jsr settestadr2
+ jsr vdcgetbyte ; and there
+ ldy #1
+ sta (ptr3),y
+ pla
+ dey
+ sta (ptr3),y
+ rts
settestadr1:
- ldy #$02 ; test page 2 (here)
- .byte $2c
+ ldy #$02 ; test page 2 (here)
+ .byte $2c
settestadr2:
- ldy #$42 ; or page 64+2 (there)
- lda #0
- jmp vdcsetsrcaddr
+ ldy #$42 ; or page 64+2 (there)
+ lda #0
+ jmp vdcsetsrcaddr
; ------------------------------------------------------------------------
; DEINSTALL routine. Is called before the driver is removed from memory.
;
DEINSTALL:
- ;on C128 restore font and clear the screen?
+ ;on C128 restore font and clear the screen?
rts
; ------------------------------------------------------------------------
; by the driver.
;
-MAP: sta curpage
- stx curpage+1
- sta ptr1+1
- ldy #0
- sty ptr1
+MAP: sta curpage
+ stx curpage+1
+ sta ptr1+1
+ ldy #0
+ sty ptr1
- lda #<window
- sta ptr2
- lda #>window
- sta ptr2+1
+ lda #<window
+ sta ptr2
+ lda #>window
+ sta ptr2+1
- jsr transferin
+ jsr transferin
lda #<window
ldx #>window
- rts
+ rts
; copy a single page from (ptr1):VDCRAM to (ptr2):RAM
transferin:
- lda ptr1
- ldy ptr1+1
- jsr vdcsetsrcaddr ; set source address in VDC
- ldy #0
- ldx #VDC_DATA
- stx VDC_ADDR_REG
-@L0: bit VDC_ADDR_REG
- bpl @L0
- lda VDC_DATA_REG ; get 2 bytes at a time to speed-up
- sta (ptr2),y ; (in fact up to 8 bytes could be fetched with special VDC config)
- iny
- lda VDC_DATA_REG
- sta (ptr2),y
- iny
- bne @L0
- rts
+ lda ptr1
+ ldy ptr1+1
+ jsr vdcsetsrcaddr ; set source address in VDC
+ ldy #0
+ ldx #VDC_DATA
+ stx VDC_ADDR_REG
+@L0: bit VDC_ADDR_REG
+ bpl @L0
+ lda VDC_DATA_REG ; get 2 bytes at a time to speed-up
+ sta (ptr2),y ; (in fact up to 8 bytes could be fetched with special VDC config)
+ iny
+ lda VDC_DATA_REG
+ sta (ptr2),y
+ iny
+ bne @L0
+ rts
; ------------------------------------------------------------------------
; USE: Tell the driver that the window is now associated with a given page.
; COMMIT: Commit changes in the memory window to extended storage.
COMMIT:
- lda curpage ; jump if no page mapped
- ldx curpage+1
- bmi done
- sta ptr1+1
- ldy #0
- sty ptr1
-
- lda #<window
- sta ptr2
- lda #>window
- sta ptr2+1
+ lda curpage ; jump if no page mapped
+ ldx curpage+1
+ bmi done
+ sta ptr1+1
+ ldy #0
+ sty ptr1
+
+ lda #<window
+ sta ptr2
+ lda #>window
+ sta ptr2+1
; fall through to transferout
; copy a single page from (ptr2):RAM to (ptr1):VDCRAM
transferout:
- lda ptr1
- ldy ptr1+1
- jsr vdcsetsrcaddr ; set source address in VDC
- ldy #0
- ldx #VDC_DATA
- stx VDC_ADDR_REG
-@L0: bit VDC_ADDR_REG
- bpl @L0
- lda (ptr2),y ; speedup does not work for writing
- sta VDC_DATA_REG
- iny
- bne @L0
- rts
+ lda ptr1
+ ldy ptr1+1
+ jsr vdcsetsrcaddr ; set source address in VDC
+ ldy #0
+ ldx #VDC_DATA
+ stx VDC_ADDR_REG
+@L0: bit VDC_ADDR_REG
+ bpl @L0
+ lda (ptr2),y ; speedup does not work for writing
+ sta VDC_DATA_REG
+ iny
+ bne @L0
+ rts
; ------------------------------------------------------------------------
; COPYFROM: Copy from extended into linear memory. A pointer to a structure
;
COPYFROM:
- jsr setup
- beq @L2 ; Skip if no full pages
+ jsr setup
+ beq @L2 ; Skip if no full pages
; Copy full pages
@L2: ldy #EM_COPY::COUNT
lda (ptr3),y ; Get bytes in last page
beq @L4
- sta tmp1
+ sta tmp1
; Transfer the bytes in the last page
- ldy #0
-@L3: jsr vdcgetbyte
- sta (ptr2),y
- iny
- dec tmp1
- lda tmp1
- bne @L3
-@L4: rts
+ ldy #0
+@L3: jsr vdcgetbyte
+ sta (ptr2),y
+ iny
+ dec tmp1
+ lda tmp1
+ bne @L3
+@L4: rts
; ------------------------------------------------------------------------
; COPYTO: Copy from linear into extended memory. A pointer to a structure
;
COPYTO:
- jsr setup
- beq @L2 ; Skip if no full pages
+ jsr setup
+ beq @L2 ; Skip if no full pages
; Copy full pages
@L2: ldy #EM_COPY::COUNT
lda (ptr3),y ; Get bytes in last page
beq @L4
- sta tmp1
+ sta tmp1
; Transfer the bytes in the last page
- ldy #0
-@L3: lda (ptr2),y
- jsr vdcputbyte
- iny
- dec tmp1
- lda tmp1
- bne @L3
-@L4: rts
+ ldy #0
+@L3: lda (ptr2),y
+ jsr vdcputbyte
+ iny
+ dec tmp1
+ lda tmp1
+ bne @L3
+@L4: rts
;-------------------------------------------------------------------------
; Helper functions to handle VDC ram
;
vdcsetsrcaddr:
- ldx #VDC_DATA_LO
- stx VDC_ADDR_REG
-@L0: bit VDC_ADDR_REG
- bpl @L0
- sta VDC_DATA_REG
- dex
- tya
- stx VDC_ADDR_REG
- sta VDC_DATA_REG
- rts
+ ldx #VDC_DATA_LO
+ stx VDC_ADDR_REG
+@L0: bit VDC_ADDR_REG
+ bpl @L0
+ sta VDC_DATA_REG
+ dex
+ tya
+ stx VDC_ADDR_REG
+ sta VDC_DATA_REG
+ rts
vdcgetbyte:
- ldx #VDC_DATA
+ ldx #VDC_DATA
vdcgetreg:
- stx VDC_ADDR_REG
-@L0: bit VDC_ADDR_REG
- bpl @L0
- lda VDC_DATA_REG
- rts
+ stx VDC_ADDR_REG
+@L0: bit VDC_ADDR_REG
+ bpl @L0
+ lda VDC_DATA_REG
+ rts
vdcputbyte:
- ldx #VDC_DATA
+ ldx #VDC_DATA
vdcputreg:
- stx VDC_ADDR_REG
-@L0: bit VDC_ADDR_REG
- bpl @L0
- sta VDC_DATA_REG
- rts
+ stx VDC_ADDR_REG
+@L0: bit VDC_ADDR_REG
+ bpl @L0
+ sta VDC_DATA_REG
+ rts
; ------------------------------------------------------------------------
; Helper function for COPYFROM and COPYTO: Store the pointer to the request
;
setup:
- sta ptr3
+ sta ptr3
stx ptr3+1 ; Save the passed em_copy pointer
ldy #EM_COPY::OFFS
lda (ptr3),y
sta ptr2+1 ; To
- ldy #EM_COPY::COUNT+1
+ ldy #EM_COPY::COUNT+1
lda (ptr3),y ; Get number of pages
sta tmp1
- rts
+ rts
projects / cc65 / blobdiff