mirror of
https://github.com/cc65/cc65.git
synced 2024-07-07 19:29:18 +00:00
d6c3bd29ac
This change was suppsed to fix the issue that the former JUMPTABLE is merked as 'ro' while it is actually written to in several scenarios. When drivers are converted using co65 and then compiled into ROMs the JUMPTABLE isn't copied to RAM and therefore the write operations in question fail. However unfortunately I didn't succeed in changing that :-( Just setting the former JUMPTABLE to 'rw' broke the drivers. So I placed the DATA segment directly after the former JUMPTABLE segment. This made the drivers converted with co65 work again - obviously after changing libsrc/Makefile:235 from '--code-label' to '--data-label'. But the actual dynamic drivers still didn't work as the former JUMPTABLE wasn't placed as the beginning of the loaded file anymore. That effect could be changed by exchanging src/ld65/o65.c:1391 with src/ld65/o65.c:1394 but doing so broke the drivers again :-((
293 lines
6.8 KiB
ArmAsm
293 lines
6.8 KiB
ArmAsm
;
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; Extended memory driver for the C128 RAM in bank #1. Driver works without
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; problems when statically linked.
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;
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; Ullrich von Bassewitz, 2002-12-04
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;
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.include "zeropage.inc"
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.include "em-kernel.inc"
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.include "em-error.inc"
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.include "c128.inc"
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.macpack generic
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; ------------------------------------------------------------------------
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; Header. Includes jump table
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.segment "HEADER"
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; Driver signature
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.byte $65, $6d, $64 ; "emd"
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.byte EMD_API_VERSION ; EM API version number
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; Library reference
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.addr $0000
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; Jump table
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.addr INSTALL
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.addr UNINSTALL
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.addr PAGECOUNT
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.addr MAP
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.addr USE
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.addr COMMIT
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.addr COPYFROM
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.addr COPYTO
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; ------------------------------------------------------------------------
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; Constants
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BASE = $400
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TOPMEM = $FF00
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PAGES = (TOPMEM - BASE) / 256
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; ------------------------------------------------------------------------
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; Data.
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.bss
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curpage: .res 1 ; Current page number
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window: .res 256 ; Memory "window"
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.code
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; ------------------------------------------------------------------------
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; INSTALL routine. Is called after the driver is loaded into memory. If
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; possible, check if the hardware is present and determine the amount of
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; memory available.
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; Must return an EM_ERR_xx code in a/x.
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;
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INSTALL:
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ldx #$FF
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stx curpage
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stx curpage+1 ; Invalidate the current page
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inx
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txa ; A = X = EM_ERR_OK
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rts
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; ------------------------------------------------------------------------
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; UNINSTALL routine. Is called before the driver is removed from memory.
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; Can do cleanup or whatever. Must not return anything.
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;
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UNINSTALL:
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rts
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; ------------------------------------------------------------------------
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; PAGECOUNT: Return the total number of available pages in a/x.
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;
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PAGECOUNT:
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lda #<PAGES
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ldx #>PAGES
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rts
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; ------------------------------------------------------------------------
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; MAP: Map the page in a/x into memory and return a pointer to the page in
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; a/x. The contents of the currently mapped page (if any) may be discarded
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; by the driver.
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;
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MAP: sta curpage
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stx curpage+1 ; Remember the new page
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clc
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adc #>BASE
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sta ptr1+1
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ldy #$00
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sty ptr1
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lda #<ptr1
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sta FETVEC
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; Transfer one page
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@L1: ldx #MMU_CFG_RAM1
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jsr FETCH
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sta window,y
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iny
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bne @L1
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; Return the memory window
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lda #<window
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ldx #>window ; Return the window address
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rts
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; ------------------------------------------------------------------------
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; USE: Tell the driver that the window is now associated with a given page.
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USE: sta curpage
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stx curpage+1 ; Remember the page
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lda #<window
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ldx #>window ; Return the window
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rts
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; ------------------------------------------------------------------------
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; COMMIT: Commit changes in the memory window to extended storage.
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COMMIT: lda curpage ; Get the current page
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ldx curpage+1
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bmi done ; Jump if no page mapped
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clc
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adc #>BASE
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sta ptr1+1
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ldy #$00
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sty ptr1
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lda #<ptr1
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sta STAVEC
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; Transfer one page. Y must be zero on entry
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@L1: lda window,y
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ldx #MMU_CFG_RAM1
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jsr STASH
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iny
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bne @L1
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; Done
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done: rts
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; ------------------------------------------------------------------------
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; COPYFROM: Copy from extended into linear memory. A pointer to a structure
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; describing the request is passed in a/x.
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; The function must not return anything.
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;
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COPYFROM:
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sta ptr3
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stx ptr3+1 ; Save the passed em_copy pointer
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ldy #EM_COPY::OFFS
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lda (ptr3),y
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sta ptr1
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ldy #EM_COPY::PAGE
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lda (ptr3),y
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clc
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adc #>BASE
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sta ptr1+1 ; From
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ldy #EM_COPY::BUF
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lda (ptr3),y
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sta ptr2
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iny
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lda (ptr3),y
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sta ptr2+1 ; To
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lda #<ptr1
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sta FETVEC
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ldy #EM_COPY::COUNT+1
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lda (ptr3),y ; Get number of pages
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beq @L2 ; Skip if no full pages
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sta tmp1
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; Copy full pages
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ldy #$00
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@L1: ldx #MMU_CFG_RAM1
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jsr FETCH
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sta (ptr2),y
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iny
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bne @L1
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inc ptr1+1
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inc ptr2+1
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dec tmp1
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bne @L1
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; Copy the remainder of the page
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@L2: ldy #EM_COPY::COUNT
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lda (ptr3),y ; Get bytes in last page
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beq @L4
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sta tmp1
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ldy #$00
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@L3: ldx #MMU_CFG_RAM1
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jsr FETCH
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sta (ptr2),y
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iny
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dec tmp1
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bne @L3
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; Done
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@L4: rts
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; ------------------------------------------------------------------------
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; COPYTO: Copy from linear into extended memory. A pointer to a structure
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; describing the request is passed in a/x.
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; The function must not return anything.
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;
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COPYTO: sta ptr3
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stx ptr3+1 ; Save the passed em_copy pointer
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ldy #EM_COPY::OFFS
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lda (ptr3),y
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sta ptr1
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ldy #EM_COPY::PAGE
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lda (ptr3),y
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clc
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adc #>BASE
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sta ptr1+1 ; To
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ldy #EM_COPY::BUF
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lda (ptr3),y
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sta ptr2
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iny
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lda (ptr3),y
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sta ptr2+1 ; From
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lda #<ptr1
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sta STAVEC
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ldy #EM_COPY::COUNT+1
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lda (ptr3),y ; Get number of pages
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beq @L2 ; Skip if no full pages
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sta tmp1
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; Copy full pages
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ldy #$00
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@L1: lda (ptr2),y
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ldx #MMU_CFG_RAM1
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jsr STASH
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iny
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bne @L1
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inc ptr1+1
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inc ptr2+1
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dec tmp1
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bne @L1
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; Copy the remainder of the page
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@L2: ldy #EM_COPY::COUNT
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lda (ptr3),y ; Get bytes in last page
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beq @L4
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sta tmp1
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ldy #$00
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@L3: lda (ptr2),y
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ldx #MMU_CFG_RAM1
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jsr STASH
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iny
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dec tmp1
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bne @L3
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; Done
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@L4: rts
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