mirror of
https://github.com/cc65/cc65.git
synced 2025-04-04 21:33:30 +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
parent
6c2fb80084
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1524b0c13f
@ -1,8 +1,11 @@
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;
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; Extended memory driver for the C128 RAM in bank #1. Driver works without
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; Extended memory driver for the C128 RAM in banks #1, #2 and #3. 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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; Updated to use banks 2 and 3 as well by
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; Marco van den Heuvel, 2010-01-21
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;
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.include "zeropage.inc"
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@ -40,17 +43,19 @@
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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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curpage: .res 2 ; Current page number
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curbank: .res 1 ; Current bank number
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copybank: .res 2 ; temp bank number
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window: .res 256 ; Memory "window"
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pagecount: .res 2 ; Number of available pages
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.code
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; ------------------------------------------------------------------------
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@ -61,12 +66,46 @@ window: .res 256 ; Memory "window"
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;
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INSTALL:
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ldx #0
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stx ptr1
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ldx #4
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stx ptr1+1
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ldx #<ptr1
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stx FETVEC
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stx STAVEC
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ldy #0
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ldx #MMU_CFG_RAM1
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jsr FETCH
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sta tmp1
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ldx #MMU_CFG_RAM3
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jsr FETCH
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cmp tmp1
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bne @has_4_banks
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tax
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inx
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txa
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ldx #MMU_CFG_RAM1
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jsr STASH
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ldx #MMU_CFG_RAM3
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jsr FETCH
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cmp tmp1
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beq @has_4_banks
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ldx #0
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lda #251
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bne @setok
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@has_4_banks:
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ldx #2
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lda #241
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@setok:
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sta pagecount
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stx pagecount+1
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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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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 ; Run into UNINSTALL instead
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; ------------------------------------------------------------------------
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; UNINSTALL routine. Is called before the driver is removed from memory.
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@ -82,8 +121,8 @@ UNINSTALL:
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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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lda pagecount
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ldx pagecount+1
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rts
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; ------------------------------------------------------------------------
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@ -92,21 +131,25 @@ PAGECOUNT:
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; by the driver.
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;
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MAP: sta curpage
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MAP: sei
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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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jsr calculate_bank_and_correct_page
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stx curbank
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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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@L1: ldx curbank
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jsr getcurbankmmu
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jsr FETCH
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sta window,y
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iny
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@ -116,6 +159,7 @@ MAP: sta curpage
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lda #<window
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ldx #>window ; Return the window address
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cli
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rts
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; ------------------------------------------------------------------------
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@ -130,15 +174,19 @@ USE: sta curpage
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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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COMMIT: sei
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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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jsr calculate_bank_and_correct_page
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stx curbank
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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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sty ptr1
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lda #<ptr1
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sta STAVEC
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@ -146,10 +194,12 @@ COMMIT: lda curpage ; Get the current page
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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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ldx curbank
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jsr getcurbankmmu
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jsr STASH
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iny
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bne @L1
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cli
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; Done
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@ -162,64 +212,55 @@ done: rts
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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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sei
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jsr setup
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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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; Setup is:
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;
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; - ptr1 contains the struct pointer
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; - ptr2 contains the linear memory buffer
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; - ptr3 contains -(count-1)
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; - ptr4 contains the page buffer and offset
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; - tmp1 contains the bank
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; - tmp2 contains zero (used for linear memory buffer offset)
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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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lda #<ptr4
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sta FETVEC
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jmp @L3
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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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@L1: ldx tmp1
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jsr getcurbankmmu
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ldy #0
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jsr FETCH
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ldy tmp2
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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 tmp2
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bne @L2
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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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@L2: inc ptr4
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beq @L4
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sta tmp1
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ldy #$00
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@L3: ldx #MMU_CFG_RAM1
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jsr FETCH
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sta (ptr2),y
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iny
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dec tmp1
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; Bump count and repeat
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@L3: inc ptr3
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bne @L1
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inc ptr3+1
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bne @L1
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cli
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rts
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; Bump page register
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@L4: inc ptr4+1
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lda ptr4+1
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cmp #$ff
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bne @L3
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lda #4
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sta ptr4+1
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inc tmp1
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@L5:
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jmp @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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@ -227,62 +268,159 @@ COPYFROM:
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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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COPYTO:
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sei
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jsr setup
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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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; Setup is:
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;
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; - ptr1 contains the struct pointer
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; - ptr2 contains the linear memory buffer
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; - ptr3 contains -(count-1)
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; - ptr4 contains the page buffer and offset
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; - tmp1 contains the bank
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; - tmp2 contains zero (used for linear memory buffer offset)
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lda #<ptr4
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sta STAVEC
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jmp @L3
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@L1:
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ldy tmp2
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lda (ptr2),y
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ldx tmp1
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jsr getcurbankmmu
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ldy #0
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jsr STASH
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inc tmp2
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bne @L2
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inc ptr2+1
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@L2: inc ptr4
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beq @L4
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; Bump count and repeat
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@L3: inc ptr3
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bne @L1
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inc ptr3+1
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bne @L1
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cli
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rts
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; Bump page register
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@L4: inc ptr4+1
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lda ptr4+1
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cmp #$ff
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bne @L3
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inc tmp1
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lda #4
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sta ptr4+1
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@L5:
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jmp @L3
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; ------------------------------------------------------------------------
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; Helper function to calculate the correct bank and page
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; when addressing bank 2 or 3
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calculate_bank_and_correct_page:
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cpx #2
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beq @calculate_bank_3_with_2
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cpx #1
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beq @calculate_bank_2_or_3_with_1
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sec
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sbc #251
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bcs @calculate_bank_2_with_0
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ldx #1
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lda curpage
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rts
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@calculate_bank_3_with_2:
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lda curpage
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clc
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adc #>BASE
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sta ptr1+1 ; To
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adc #10
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@calculate_bank_3_with_1:
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ldx #3
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rts
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@calculate_bank_2_or_3_with_1:
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sec
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sbc #246
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bcs @calculate_bank_3_with_1
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lda curpage
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clc
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adc #5
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@calculate_bank_2_with_0:
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ldx #2
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rts
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; ------------------------------------------------------------------------
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; Helper function to get the correct mmu value in x
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getcurbankmmu:
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cpx #1
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beq @bank1
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cpx #2
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beq @bank2
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ldx #MMU_CFG_RAM3
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rts
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@bank2:
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ldx #MMU_CFG_RAM2
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rts
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@bank1:
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ldx #MMU_CFG_RAM1
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rts
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; ------------------------------------------------------------------------
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; Helper function for COPYFROM and COPYTO: Store the pointer to the request
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; structure and prepare data for the copy
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setup: sta ptr1
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stx ptr1+1 ; Save passed pointer
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; Get the page number from the struct and adjust it so that it may be used
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; with the hardware. That is: page pointer in ptr4 and bank in tmp1
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ldy #EM_COPY::PAGE+1
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lda (ptr1),y
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tax
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dey
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lda (ptr1),y
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sta curpage
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jsr calculate_bank_and_correct_page
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clc
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adc #4
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sta ptr4+1
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stx tmp1
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; Get the buffer pointer into ptr2
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ldy #EM_COPY::BUF
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lda (ptr3),y
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lda (ptr1),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),y
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sta ptr2+1
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lda #<ptr1
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sta STAVEC
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; Get the count, calculate -(count-1) and store it into ptr3
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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 #$00
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@L1: lda (ptr2),y
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ldx #MMU_CFG_RAM1
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jsr STASH
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ldy #EM_COPY::COUNT
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lda (ptr1),y
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eor #$FF
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sta ptr3
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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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lda (ptr1),y
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eor #$FF
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sta ptr3+1
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; Copy the remainder of the page
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; Get the page offset into the low byte of ptr4 clear tmp2
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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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ldy #EM_COPY::OFFS
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lda (ptr1),y
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sta ptr4
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lda #0
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sta tmp2
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; Done
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@L4: rts
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rts
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