BASE = $4000
PAGES = 3 * 256
-CHECKC256K = $0200
-TRANSFERC256K = $0200
-STASHOPCODE = $91
-pia = $DFC0
+TARGETLOC = $200 ; Target location for copy/check code
+PIA = $DFC0
; ------------------------------------------------------------------------
; Data.
; This function is used to copy code from and to the extended memory
-.proc c256kcopycode
-.org ::TRANSFERC256K ; Assemble for target location
- stx pia
-::STASHC256K := * ; Location and opcode is patched at runtime
-::VECC256K := *+1
+.proc copy
+template:
+.org ::TARGETLOC ; Assemble for target location
+entry:
+ stx PIA
+stashop = $91 ; 'sta' opcode
+operation := * ; Location and opcode is patched at runtime
+address := *+1
lda ($00),y
ldx #$dc
- stx pia
+ stx PIA
rts
.reloc
.endproc
; This function is used to check for the existence of the extended memory
-.proc c256kcheckcode
-.org ::CHECKC256K
+.proc check
+template:
+.org ::TARGETLOC
+entry:
ldy #$00 ; Assume hardware not present
lda #$fc
- sta pia
+ sta PIA
lda $01
tax
and #$f8
iny
done: stx $01
ldx #$dc
- stx pia
+ stx PIA
rts
.reloc
.endproc
; Since the functions above are copied to $200, the current contents of this
; memory area must be saved into backup storage. Allocate enough space.
-backup: .res .max (.sizeof (c256kcopycode), .sizeof (c256kcheckcode))
+backup: .res .max (.sizeof (copy), .sizeof (check))
;
INSTALL:
- lda pia+1 ; Select Peripheral Registers
+ lda PIA+1 ; Select Peripheral Registers
ora #4
- sta pia+1
+ sta PIA+1
tax
- lda pia+3
+ lda PIA+3
ora #4
- sta pia+3
+ sta PIA+3
tay
lda #$DC ; Set the default memory bank data
- sta pia
+ sta PIA
lda #$FE
- sta pia+2
+ sta PIA+2
txa ; Select Data Direction Registers
and #$FB
- sta pia+1
+ sta PIA+1
tya
and #$FB
- sta pia+3
+ sta PIA+3
lda #$FF ; Set the ports to output
- sta pia
- sta pia+2
+ sta PIA
+ sta PIA+2
txa
and #$C7
ora #$30 ; Set CA1 and
- sta pia+1 ; select Peripheral Registers
- sty pia+3
+ sta PIA+1 ; select Peripheral Registers
+ sty PIA+3
jsr backup_and_setup_check_routine
- jsr CHECKC256K
+ jsr check::entry
cli
- ldx #.sizeof (c256kcheckcode) - 1
+ ldx #.sizeof (check) - 1
jsr restore_data
cpy #$01
beq @present
@present:
lda #<EM_ERR_OK
ldx #>EM_ERR_OK
-; rts ; Run into UNINSTALL instead
+; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
MAP:
sei
- sta curpage ; Remember the new page
+ sta curpage ; Remember the new page
stx curpage+1
jsr adjust_page_and_bank
stx curbank
sty ptr1
jsr backup_and_setup_copy_routine
ldx #<ptr1
- stx VECC256K
+ stx copy::address
@L1:
ldx curbank
- jsr TRANSFERC256K
+ jsr copy::entry
ldx ptr1
sta window,x
inc ptr1
jsr restore_copy_routine
lda #<window
- ldx #>window ; Return the window address
+ ldx #>window ; Return the window address
cli
rts
; ------------------------------------------------------------------------
; USE: Tell the driver that the window is now associated with a given page.
-USE: sta curpage ; Remember the page
+USE: sta curpage ; Remember the page
stx curpage+1
lda #<window
- ldx #>window ; Return the window
+ ldx #>window ; Return the window
rts
; ------------------------------------------------------------------------
COMMIT:
sei
- lda curpage ; Get the current page
+ lda curpage ; Get the current page
ldx curpage+1
jsr adjust_page_and_bank
sty ptr1
jsr backup_and_setup_copy_routine
ldx #<ptr1
- stx VECC256K
- ldx #<STASHOPCODE
- stx STASHC256K
+ stx copy::address
+ ldx #<copy::stashop
+ stx copy::operation
@L1:
ldx ptr1
lda window,x
ldx curbank
- jsr TRANSFERC256K
+ jsr copy::entry
inc ptr1
bne @L1
; - tmp2 contains the bank value
lda #<ptr4
- sta VECC256K
+ sta copy::address
jmp @L3
@L1:
ldx tmp2
ldy #0
- jsr TRANSFERC256K
+ jsr copy::entry
ldy tmp1
sta (ptr2),y
inc tmp1
; - tmp2 contains the bank value
lda #<ptr4
- sta VECC256K
- lda #<STASHOPCODE
- sta STASHC256K
+ sta copy::address
+ lda #<copy::stashop
+ sta copy::operation
jmp @L3
@L1:
lda (ptr2),y
ldx tmp2
ldy #0
- jsr TRANSFERC256K
+ jsr copy::entry
inc tmp1
bne @L2
inc ptr2+1
setup:
sta ptr1
- stx ptr1+1 ; Save passed pointer
+ stx ptr1+1 ; Save passed pointer
; Get the page number from the struct and adjust it so that it may be used
; with the hardware. That is: ptr4 has the page address and page offset
; Helper routines for copying to and from the +256k ram
backup_and_setup_copy_routine:
- ldx #.sizeof (c256kcopycode) - 1
+ ldx #.sizeof (copy) - 1
@L1:
- lda TRANSFERC256K,x
+ lda copy::entry,x
sta backup,x
- lda c256kcopycode,x
- sta TRANSFERC256K,x
+ lda copy::template,x
+ sta copy::entry,x
dex
bpl @L1
rts
backup_and_setup_check_routine:
- ldx #.sizeof (c256kcheckcode) - 1
+ ldx #.sizeof (check) - 1
@L1:
- lda CHECKC256K,x
+ lda check::entry,x
sta backup,x
- lda c256kcheckcode,x
- sta CHECKC256K,x
+ lda check::template,x
+ sta check::entry,x
dex
bpl @L1
rts
restore_copy_routine:
- ldx #.sizeof (c256kcopycode) - 1
+ ldx #.sizeof (copy) - 1
restore_data:
lda backup,x
- sta CHECKC256K,x
+ sta TARGETLOC,x
dex
bpl restore_data
rts
projects / cc65 / blobdiff