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|
;
; Extended memory driver for the Atari 130XE memory standard
; Shawn Jefferson, 2012-08-11
;
; Banking Register $D301:
; Bit 7: Self-Test on/off
; Bit 6: Unused
; Bit 5: Antic sees bank
; Bit 4: CPU sees bank
; Bit 3: bank control
; Bit 2: bank control
; Bit 1: BASIC on/off
; Bit 0: OS RAM on/off
;
; Masks: %11100011 $E3 Bank 0
; %11100111 $E7 Bank 1
; %11101011 $EB Bank 2
; %11101111 $EF Bank 3
; %11111111 $FF Off
;
; Based on the Extended memory driver for the Apple II auxiliary memory
; by
; Stefan Haubenthal, 2003-12-12
; Ullrich von Bassewitz, 2002-12-02
;
.include "zeropage.inc"
.include "em-kernel.inc"
.include "em-error.inc"
.macpack generic
.macpack module
; ------------------------------------------------------------------------
; Header. Includes jump table
.ifdef __ATARIXL__
module_header _atrx130_emd
.else
module_header _atr130_emd
.endif
; Driver signature
.byte $65, $6d, $64 ; "emd"
.byte EMD_API_VERSION ; EM API version number
; Library reference
.addr $0000
; Jump table
.addr INSTALL
.addr UNINSTALL
.addr PAGECOUNT
.addr MAP
.addr USE
.addr COMMIT
.addr COPYFROM
.addr COPYTO
; ------------------------------------------------------------------------
; Constants
BANK = $4000 ; bank window
STACK = $0100 ; stack location
PAGES = 256 ; 4 x 16k banks
; ------------------------------------------------------------------------
; Data.
.rodata
banks: .byte $E3,$E7,$EB,$EF ; 130XE banks for cpu banking
stacktest: sei
ldy banks
sty $D301
tax ; A is set by caller
inx
stx $4000 ; change $4000
ldy #$FF ; STACK+13
sty $D301
cmp $4000 ; changed?
beq @1
sec ; error
bcs @2
@1: clc
@2: sta $4000 ; restore
cli
rts
stacktest_end:
stackcopy: sei ; disable interrupts
@1: dex ; pre-decrement (full page x=0)
ldy #$FF ; this will be replaced STACK+3
sty $D301 ; set bank
lda $FF00,x ; address to copy from STACK+8,+9
ldy #$FF ; this will be replaced STACK+11
sty $D301
sta $FF00,x ; address to copy to STACK+16,+17
cpx #0
bne @1
ldy #$FF ; portb_save STACK+23
sty $D301
cli ; enable interrupts
rts
stackcopy_end:
stackcopy_byte: sei
ldy #$FF ; STACK+2
sty $D301
lda $FFFF ; STACK+7 +8
ldy #$FF ; STACK+10
sty $D301
sta $FFFF ; STACK+15 +16
ldy #$FF ; STACK+18
sty $D301
cli
rts
stackcopy_byte_end:
.data
curpage: .byte $FF ; Current page number in bank (invalid)
curbank: .byte $FF ; Current bank number
.bss
window: .res 256 ; Memory "window"
portb_save: .res 1 ; portb state
.code
install_transfer:
ldx #stackcopy_end - stackcopy - 1
@1: lda stackcopy,x
sta STACK,x
dex
bpl @1
rts
install_byte_transfer:
ldx #stackcopy_byte_end - stackcopy_byte - 1
@2: lda stackcopy_byte,x
sta STACK,x
dex
bpl @2
rts
install_test:
ldx #stacktest_end - stacktest - 1
@3: lda stacktest,x
sta STACK,x
dex
bpl @3
rts
setpage:
tax ; save page
and #$C0 ; mask out bank
clc
ror
ror ; divide by 64
ror ; 64 pages in each bank
ror
ror
ror
sta curbank ; Remember the new bank
txa ; bring back page
and #$3F ; mask out page
sta curpage ; curpage in bank
rts
; ------------------------------------------------------------------------
; INSTALL routine. Is called after the driver is loaded into memory. If
; possible, check if the hardware is present and determine the amount of
; memory available.
; Must return an EM_ERR_xx code in a/x.
;
INSTALL:
lda $D301 ; save state of portb
sta portb_save
tay
jsr install_test ; doesn't touch Y
sty STACK+13
lda $4000 ; test for extended memory
jsr STACK
bcs @1
lda #EM_ERR_OK
rts
@1: lda #EM_ERR_NO_DEVICE
rts
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
; Can do cleanup or whatever. Must not return anything.
;
UNINSTALL:
rts
; ------------------------------------------------------------------------
; PAGECOUNT: Return the total number of available pages in a/x.
;
PAGECOUNT:
lda #<PAGES
ldx #>PAGES
rts
; ------------------------------------------------------------------------
; MAP: Map the page in a/x into memory and return a pointer to the page in
; a/x. The contents of the currently mapped page (if any) may be discarded
; by the driver.
;
MAP: jsr setpage ; extract the bank/page
add #>BANK ; $4000 + page (carry is cleared)
sta ptr1+1
;ldy #$00
;sty ptr1
lda #<window
sta ptr2
lda #>window
sta ptr2+1
; Transfer one page
jsr install_transfer ; Transfer one page
ldx curbank
lda banks,x
sta STACK+3 ; set bank to copy from
; lda ptr1
; sta STACK+8
lda ptr1+1
sta STACK+9 ; set copy from address
lda portb_save
sta STACK+11 ; set portb restore
sta STACK+23 ; set final portb restore
lda ptr2
sta STACK+16
lda ptr2+1
sta STACK+17 ; set copy to address
ldx #0 ; full page copy
jsr STACK ; do the copy!
; Return the memory window
lda #<window
ldx #>window ; Return the window address
rts
; ------------------------------------------------------------------------
; USE: Tell the driver that the window is now associated with a given page.
USE: ;sta curpage ; Remember the page
jsr setpage ; extract bank/page
lda #<window
ldx #>window ; Return the window
rts
; ------------------------------------------------------------------------
; COMMIT: Commit changes in the memory window to extended storage.
COMMIT: lda curpage ; Get the current page
cmp #$FF
beq commit_done ; Jump if no page mapped
clc
add #>BANK
sta ptr2+1
;ldy #$00
;sty ptr2
lda #<window
sta ptr1
lda #>window
sta ptr1+1
; Transfer one page/all bytes
jsr install_transfer ; Transfer one page
lda portb_save
sta STACK+3 ; set bank to copy from
sta STACK+23 ; set final portb restore
lda ptr1
sta STACK+8
lda ptr1+1
sta STACK+9 ; set copy from address
ldx curbank
lda banks,x
sta STACK+11 ; set bank to copy to
;lda ptr2
;sta STACK+16
lda ptr2+1
sta STACK+17 ; set copy to address
ldx #0 ; full page copy
jsr STACK ; do the copy!
commit_done:
rts
; ------------------------------------------------------------------------
; COPYFROM: Copy from extended into linear memory. A pointer to a structure
; describing the request is passed in a/x.
; The function must not return anything.
;
COPYFROM:
sta ptr3
stx ptr3+1 ; Save the passed em_copy pointer
jsr install_byte_transfer ; install the stack copy routine
ldy #EM_COPY::OFFS
lda (ptr3),y
sta STACK+7 ; offset goes into BANK low
ldy #EM_COPY::PAGE
lda (ptr3),y
sta tmp1 ; save page for later
;add #>BANK
;sta STACK+8 ; BANK + page goes into BANK high
ldy #EM_COPY::BUF
lda (ptr3),y
sta STACK+15 ; buffer goes into dest low
iny
lda (ptr3),y
sta STACK+16 ; buffer goes into dest high
ldy #EM_COPY::COUNT
lda (ptr3),y ; Get bytes in last page
sta ptr4
iny
lda (ptr3),y ; Get number of pages
sta ptr4+1
lda tmp1 ; extract bank/page
jsr setpage ; sets curbank/curpage
lda curpage
add #>BANK ; add to BANK address
sta STACK+8 ; current page in bank
ldx curbank
lda banks,x
sta STACK+2 ; set bank in stack
lda portb_save
sta STACK+10 ; set bank restore in stack
sta STACK+18 ; set final restore too
copyfrom_copy:
lda ptr4 ; check if count is zero
bne @4
lda ptr4+1
beq done
@4: jsr STACK ; copy one byte
sec
lda ptr4
sub #1
sta ptr4
bcs @1
lda ptr4+1
beq @1
sub #1
sta ptr4+1
@1: inc STACK+7 ; increment address in BANK
bne @2
inc STACK+8
lda STACK+8
cmp #$80 ; we stepped outside bank
bne @2
inc curbank ; get next bank
ldx curbank
lda banks,x
sta STACK+2 ; set new bank
lda #$40 ; set address back to $4000
sta STACK+8
@2: inc STACK+15 ; increment buffer address
bne @3
inc STACK+16
@3: jmp copyfrom_copy ; copy another byte
done:
rts
; ------------------------------------------------------------------------
; COPYTO: Copy from linear into extended memory. A pointer to a structure
; describing the request is passed in a/x.
; The function must not return anything.
;
COPYTO:
sta ptr3
stx ptr3+1 ; Save the passed em_copy pointer
jsr install_byte_transfer ; install the stack copy routine
ldy #EM_COPY::OFFS
lda (ptr3),y
sta STACK+15 ; offset goes into BANK low
ldy #EM_COPY::PAGE
lda (ptr3),y
sta tmp1 ; save page for later
;add #>BANK
;sta STACK+16 ; BANK + page goes into BANK high
ldy #EM_COPY::BUF
lda (ptr3),y
sta STACK+7 ; buffer goes into dest low
iny
lda (ptr3),y
sta STACK+8 ; buffer goes into dest high
ldy #EM_COPY::COUNT
lda (ptr3),y ; Get bytes in last page
sta ptr4
iny
lda (ptr3),y ; Get number of pages
sta ptr4+1
lda tmp1 ; extract bank/page
jsr setpage ; sets curbank/curpage
lda curpage
add #>BANK ; add to BANK address
sta STACK+16 ; current page in bank
ldx curbank
lda banks,x
sta STACK+10 ; set bank in stack
lda portb_save
sta STACK+2 ; set bank restore in stack
sta STACK+18 ; set final restore too
copyto_copy:
lda ptr4 ; check if count is zero
bne @4
lda ptr4+1
beq done
@4: jsr STACK ; copy one byte
sec
lda ptr4
sub #1
sta ptr4
bcs @1
lda ptr4+1
beq @1
sub #1
sta ptr4+1
@1: inc STACK+15 ; increment address in BANK
bne @2
inc STACK+16
lda STACK+16
cmp #$80 ; we stepped outside bank
bne @2
inc curbank ; get next bank
ldx curbank
lda banks,x
sta STACK+10 ; set new bank
lda #$40 ; set address back to $4000
sta STACK+16
@2: inc STACK+7 ; increment buffer address
bne @3
inc STACK+8
@3: jmp copyto_copy ; copy another byte
|
