Started new driver for the CBM REU
git-svn-id: svn://svn.cc65.org/cc65/trunk@1680 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz
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2 changed files with 224 additions and 2 deletions
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@ -35,7 +35,7 @@ OBJS = _scrsize.o \
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TGIS = c64-320-200-2.tgi
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EMDS = c64-georam.emd
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EMDS = c64-georam.emd c64-reu.emd
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#--------------------------------------------------------------------------
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# Targets
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@ -47,5 +47,5 @@ all: $(OBJS) $(EMDS) $(TGIS)
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clean:
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@rm -f $(OBJS) $(EMDS:.emd=.o) $(TGIS:.tgi=.o)
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@rm -f $(OBJS) $(EMDS:.emd=.o) $(TGIS:.tgi=.o)
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222
libsrc/c64/c64-reu.s
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222
libsrc/c64/c64-reu.s
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@ -0,0 +1,222 @@
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;
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; Extended memory driver for the Commodore REU
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;
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; Ullrich von Bassewitz, 2002-11-29
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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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.macpack generic
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; ------------------------------------------------------------------------
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; Header. Includes jump table
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.segment "JUMPTABLE"
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; Driver signature
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.byte $65, $6d, $64 ; "emd"
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.byte $00 ; EM API version number
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; Jump table.
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.word INSTALL
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.word DEINSTALL
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.word PAGECOUNT
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.word MAP
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.word MAPCLEAN
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.word COPYFROM
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.word COPYTO
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; ------------------------------------------------------------------------
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; Constants
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REU_STATUS = $DF00 ; Status register
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REU_COMMAND = $DF01 ; Command register
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REU_C64ADDR = $DF02 ; C64 base address register
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REU_REUADDR = $DF04 ; REU base address register
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REU_COUNT = $DF07 ; Transfer count register
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REU_IRQMASK = $DF09 ; IRQ mask register
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REU_CONTROL = $DF0A ; Control register
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OP_COPYFROM = $ED
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OP_COPYTO = $EC
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; ------------------------------------------------------------------------
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; Data.
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.data
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pagecount: .res 2 ; Number of pages available
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curpage: .word $FFFF ; Current page number (invalid)
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.bss
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window: .res 256 ; Memory "window"
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reu_params: .word $0000 ; Host address, lo, hi
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.word $0000 ; Exp address, lo, hi
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.byte $00 ; Expansion bank no.
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.word $0000 ; # bytes to move, lo, hi
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.byte $00 ; Interrupt mask reg.
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.byte $00 ; Adress control reg.
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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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lda #$55
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sta REU_REUADDR
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cmp REU_REUADDR ; Check for presence of REU
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bne nodevice
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lda #$AA
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sta REU_REUADDR
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cmp REU_REUADDR ; Check for presence of REU
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bne nodevice
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ldx #>(128*4) ; Assume 128KB
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lda REU_STATUS
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and #$10 ; Check size bit
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beq @L1
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ldx #>(256*4) ; 256KB when size bit is set
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@L1: stx pagecount+1
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lda #<EM_ERR_OK
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ldx #>EM_ERR_OK
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rts
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; No REU found
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nodevice:
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lda #<EM_ERR_NO_DEVICE
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ldx #>EM_ERR_NO_DEVICE
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rts
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; ------------------------------------------------------------------------
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; DEINSTALL 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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DEINSTALL:
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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 pagecount
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ldx pagecount+1
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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) are assumed to be
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; dirty and must be saved into secondary storage if this is necessary.
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;
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MAP: ldy curpage+1 ; Do we have a page mapped?
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bmi MAPCLEAN ; Jump if no page mapped
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ldy #<window
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sty REU_C64ADDR
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ldy #>window
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sty REU_C64ADDR+1
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ldy #0
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sty REU_COUNT+0
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sty REU_REUADDR+0
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ldy curpage
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sty REU_REUADDR+1
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ldy curpage+1
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sty REU_REUADDR+2
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ldy #1
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sty REU_COUNT+1 ; Move 256 bytes
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ldy #OP_COPYTO
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pha
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jsr Transfer ; Transfer 256 bytes into REU
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pla
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; Run straight into MAPCLEAN
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; ------------------------------------------------------------------------
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; MAPCLEAN: Map the page in a/x into memory and return a pointer to the page
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; in a/x. The contents of the currently mapped page (if any) are assumed to
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; be clean, so if this is an advantage for the driver, the current contents
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; may be discarded.
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MAPCLEAN:
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sta curpage
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stx curpage+1 ; Remember the new page
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ldy #<window
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sty REU_C64ADDR
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ldy #>window
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sty REU_C64ADDR+1
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ldy #0
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sty REU_COUNT+0
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sty REU_REUADDR+0
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sta REU_REUADDR+1
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stx REU_REUADDR+2
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ldy #1
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sty REU_COUNT+1 ; Move 256 bytes
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ldy #OP_COPYFROM
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jsr Transfer ; Transfer 256 bytes into REU
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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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; 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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; ------------------------------------------------------------------------
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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:
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lda #0
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tax
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rts
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; ---------------------------------------------------------------------------
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; Transfer subroutine for the REU. Expects command in Y.
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Transfer:
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sty $df01 ; Issue command
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sei ; Save the value of the
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ldy $01 ; the c64 control port
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tya ; and turn on lower 3 bits
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ora #$03 ; to bank out ROMs, I/O.
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sta $01
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lda $ff00
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sta $ff00 ; Now start transfer...
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sty $01 ; Restore the old configuration
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cli
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rts
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