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mirror of https://github.com/cc65/cc65.git synced 2024-06-08 15:29:37 +00:00

Added code to the driver to use also banks 2 and 3 if present. Contributed by

Marco van den Heuvel.


git-svn-id: svn://svn.cc65.org/cc65/trunk@4569 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2010-02-01 17:56:37 +00:00
parent 6c2fb80084
commit 1524b0c13f

View File

@ -1,8 +1,11 @@
;
; Extended memory driver for the C128 RAM in bank #1. Driver works without
; Extended memory driver for the C128 RAM in banks #1, #2 and #3. Driver works without
; problems when statically linked.
;
; Ullrich von Bassewitz, 2002-12-04
;
; Updated to use banks 2 and 3 as well by
; Marco van den Heuvel, 2010-01-21
;
.include "zeropage.inc"
@ -40,17 +43,19 @@
; Constants
BASE = $400
TOPMEM = $FF00
PAGES = (TOPMEM - BASE) / 256
; ------------------------------------------------------------------------
; Data.
.bss
curpage: .res 1 ; Current page number
curpage: .res 2 ; Current page number
curbank: .res 1 ; Current bank number
copybank: .res 2 ; temp bank number
window: .res 256 ; Memory "window"
pagecount: .res 2 ; Number of available pages
.code
; ------------------------------------------------------------------------
@ -61,12 +66,46 @@ window: .res 256 ; Memory "window"
;
INSTALL:
ldx #0
stx ptr1
ldx #4
stx ptr1+1
ldx #<ptr1
stx FETVEC
stx STAVEC
ldy #0
ldx #MMU_CFG_RAM1
jsr FETCH
sta tmp1
ldx #MMU_CFG_RAM3
jsr FETCH
cmp tmp1
bne @has_4_banks
tax
inx
txa
ldx #MMU_CFG_RAM1
jsr STASH
ldx #MMU_CFG_RAM3
jsr FETCH
cmp tmp1
beq @has_4_banks
ldx #0
lda #251
bne @setok
@has_4_banks:
ldx #2
lda #241
@setok:
sta pagecount
stx pagecount+1
ldx #$FF
stx curpage
stx curpage+1 ; Invalidate the current page
inx
txa ; A = X = EM_ERR_OK
rts
stx curpage+1 ; Invalidate the current page
inx
txa ; A = X = EM_ERR_OK
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.
@ -82,8 +121,8 @@ UNINSTALL:
;
PAGECOUNT:
lda #<PAGES
ldx #>PAGES
lda pagecount
ldx pagecount+1
rts
; ------------------------------------------------------------------------
@ -92,21 +131,25 @@ PAGECOUNT:
; by the driver.
;
MAP: sta curpage
MAP: sei
sta curpage
stx curpage+1 ; Remember the new page
clc
adc #>BASE
sta ptr1+1
ldy #$00
sty ptr1
jsr calculate_bank_and_correct_page
stx curbank
clc
adc #>BASE
sta ptr1+1
ldy #$00
sty ptr1
lda #<ptr1
sta FETVEC
; Transfer one page
@L1: ldx #MMU_CFG_RAM1
@L1: ldx curbank
jsr getcurbankmmu
jsr FETCH
sta window,y
iny
@ -116,6 +159,7 @@ MAP: sta curpage
lda #<window
ldx #>window ; Return the window address
cli
rts
; ------------------------------------------------------------------------
@ -130,15 +174,19 @@ USE: sta curpage
; ------------------------------------------------------------------------
; COMMIT: Commit changes in the memory window to extended storage.
COMMIT: lda curpage ; Get the current page
COMMIT: sei
lda curpage ; Get the current page
ldx curpage+1
bmi done ; Jump if no page mapped
jsr calculate_bank_and_correct_page
stx curbank
clc
adc #>BASE
sta ptr1+1
ldy #$00
sty ptr1
sty ptr1
lda #<ptr1
sta STAVEC
@ -146,10 +194,12 @@ COMMIT: lda curpage ; Get the current page
; Transfer one page. Y must be zero on entry
@L1: lda window,y
ldx #MMU_CFG_RAM1
ldx curbank
jsr getcurbankmmu
jsr STASH
iny
bne @L1
cli
; Done
@ -162,64 +212,55 @@ done: rts
;
COPYFROM:
sta ptr3
stx ptr3+1 ; Save the passed em_copy pointer
sei
jsr setup
ldy #EM_COPY::OFFS
lda (ptr3),y
sta ptr1
ldy #EM_COPY::PAGE
lda (ptr3),y
clc
adc #>BASE
sta ptr1+1 ; From
; Setup is:
;
; - ptr1 contains the struct pointer
; - ptr2 contains the linear memory buffer
; - ptr3 contains -(count-1)
; - ptr4 contains the page buffer and offset
; - tmp1 contains the bank
; - tmp2 contains zero (used for linear memory buffer offset)
ldy #EM_COPY::BUF
lda (ptr3),y
sta ptr2
iny
lda (ptr3),y
sta ptr2+1 ; To
lda #<ptr1
lda #<ptr4
sta FETVEC
jmp @L3
ldy #EM_COPY::COUNT+1
lda (ptr3),y ; Get number of pages
beq @L2 ; Skip if no full pages
sta tmp1
; Copy full pages
ldy #$00
@L1: ldx #MMU_CFG_RAM1
@L1: ldx tmp1
jsr getcurbankmmu
ldy #0
jsr FETCH
ldy tmp2
sta (ptr2),y
iny
bne @L1
inc ptr1+1
inc tmp2
bne @L2
inc ptr2+1
dec tmp1
bne @L1
; Copy the remainder of the page
@L2: ldy #EM_COPY::COUNT
lda (ptr3),y ; Get bytes in last page
@L2: inc ptr4
beq @L4
sta tmp1
ldy #$00
@L3: ldx #MMU_CFG_RAM1
jsr FETCH
sta (ptr2),y
iny
dec tmp1
; Bump count and repeat
@L3: inc ptr3
bne @L1
inc ptr3+1
bne @L1
cli
rts
; Bump page register
@L4: inc ptr4+1
lda ptr4+1
cmp #$ff
bne @L3
lda #4
sta ptr4+1
inc tmp1
@L5:
jmp @L3
; Done
@L4: rts
; ------------------------------------------------------------------------
; COPYTO: Copy from linear into extended memory. A pointer to a structure
@ -227,62 +268,159 @@ COPYFROM:
; The function must not return anything.
;
COPYTO: sta ptr3
stx ptr3+1 ; Save the passed em_copy pointer
COPYTO:
sei
jsr setup
ldy #EM_COPY::OFFS
lda (ptr3),y
sta ptr1
ldy #EM_COPY::PAGE
lda (ptr3),y
; Setup is:
;
; - ptr1 contains the struct pointer
; - ptr2 contains the linear memory buffer
; - ptr3 contains -(count-1)
; - ptr4 contains the page buffer and offset
; - tmp1 contains the bank
; - tmp2 contains zero (used for linear memory buffer offset)
lda #<ptr4
sta STAVEC
jmp @L3
@L1:
ldy tmp2
lda (ptr2),y
ldx tmp1
jsr getcurbankmmu
ldy #0
jsr STASH
inc tmp2
bne @L2
inc ptr2+1
@L2: inc ptr4
beq @L4
; Bump count and repeat
@L3: inc ptr3
bne @L1
inc ptr3+1
bne @L1
cli
rts
; Bump page register
@L4: inc ptr4+1
lda ptr4+1
cmp #$ff
bne @L3
inc tmp1
lda #4
sta ptr4+1
@L5:
jmp @L3
; ------------------------------------------------------------------------
; Helper function to calculate the correct bank and page
; when addressing bank 2 or 3
calculate_bank_and_correct_page:
cpx #2
beq @calculate_bank_3_with_2
cpx #1
beq @calculate_bank_2_or_3_with_1
sec
sbc #251
bcs @calculate_bank_2_with_0
ldx #1
lda curpage
rts
@calculate_bank_3_with_2:
lda curpage
clc
adc #>BASE
sta ptr1+1 ; To
adc #10
@calculate_bank_3_with_1:
ldx #3
rts
@calculate_bank_2_or_3_with_1:
sec
sbc #246
bcs @calculate_bank_3_with_1
lda curpage
clc
adc #5
@calculate_bank_2_with_0:
ldx #2
rts
; ------------------------------------------------------------------------
; Helper function to get the correct mmu value in x
getcurbankmmu:
cpx #1
beq @bank1
cpx #2
beq @bank2
ldx #MMU_CFG_RAM3
rts
@bank2:
ldx #MMU_CFG_RAM2
rts
@bank1:
ldx #MMU_CFG_RAM1
rts
; ------------------------------------------------------------------------
; Helper function for COPYFROM and COPYTO: Store the pointer to the request
; structure and prepare data for the copy
setup: sta ptr1
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: page pointer in ptr4 and bank in tmp1
ldy #EM_COPY::PAGE+1
lda (ptr1),y
tax
dey
lda (ptr1),y
sta curpage
jsr calculate_bank_and_correct_page
clc
adc #4
sta ptr4+1
stx tmp1
; Get the buffer pointer into ptr2
ldy #EM_COPY::BUF
lda (ptr3),y
lda (ptr1),y
sta ptr2
iny
lda (ptr3),y
sta ptr2+1 ; From
lda (ptr1),y
sta ptr2+1
lda #<ptr1
sta STAVEC
; Get the count, calculate -(count-1) and store it into ptr3
ldy #EM_COPY::COUNT+1
lda (ptr3),y ; Get number of pages
beq @L2 ; Skip if no full pages
sta tmp1
; Copy full pages
ldy #$00
@L1: lda (ptr2),y
ldx #MMU_CFG_RAM1
jsr STASH
ldy #EM_COPY::COUNT
lda (ptr1),y
eor #$FF
sta ptr3
iny
bne @L1
inc ptr1+1
inc ptr2+1
dec tmp1
bne @L1
lda (ptr1),y
eor #$FF
sta ptr3+1
; Copy the remainder of the page
; Get the page offset into the low byte of ptr4 clear tmp2
@L2: ldy #EM_COPY::COUNT
lda (ptr3),y ; Get bytes in last page
beq @L4
sta tmp1
ldy #$00
@L3: lda (ptr2),y
ldx #MMU_CFG_RAM1
jsr STASH
iny
dec tmp1
bne @L3
ldy #EM_COPY::OFFS
lda (ptr1),y
sta ptr4
lda #0
sta tmp2
; Done
@L4: rts
rts