Added C64 RAM driver, fixed bug in REU driver

git-svn-id: svn://svn.cc65.org/cc65/trunk@1699 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/c64/Makefile

@@ -45,7 +45,7 @@ OBJS = 	_scrsize.o     	 	\
 
 TGIS =	c64-320-200-2.tgi
 
-EMDS =	c64-georam.emd c64-reu.emd
+EMDS =	c64-georam.emd c64-ram.emd c64-reu.emd
 
 #--------------------------------------------------------------------------
 # Targets

libsrc/c64/c64-ram.s

@@ -0,0 +1,281 @@
+;
+; Extended memory driver for the C64 hidden RAM
+;
+; Ullrich von Bassewitz, 2002-12-02
+;
+
+	.include 	"zeropage.inc"
+
+      	.include 	"em-kernel.inc"
+        .include        "em-error.inc"
+
+
+        .macpack        generic
+
+
+; ------------------------------------------------------------------------
+; Header. Includes jump table
+
+.segment        "JUMPTABLE"
+
+; Driver signature
+
+        .byte   $65, $6d, $64           ; "emd"
+        .byte   $00                     ; EM API version number
+
+; Jump table.
+
+        .word   INSTALL
+        .word   DEINSTALL
+        .word   PAGECOUNT
+        .word   MAP
+        .word   COMMIT
+	.word	COPYFROM
+        .word   COPYTO
+
+; ------------------------------------------------------------------------
+; Constants
+
+BASE	= $D000
+PAGES  	= ($10000 - BASE) / 256
+
+; ------------------------------------------------------------------------
+; Data.
+
+.data
+curpage:        .byte	$FF		; Current page number (invalid)
+
+.bss
+window:         .res    256             ; Memory "window"
+
+.code
+
+; ------------------------------------------------------------------------
+; INSTALL routine. Is called after the driver is loaded into memory. If
+; possible, check if the hardware is present and determine the amount of
+; memory available.
+; Must return an EM_ERR_xx code in a/x.
+;
+
+INSTALL:
+        lda     #<EM_ERR_OK
+        ldx     #>EM_ERR_OK
+        rts
+
+; ------------------------------------------------------------------------
+; DEINSTALL routine. Is called before the driver is removed from memory.
+; Can do cleanup or whatever. Must not return anything.
+;
+
+DEINSTALL:
+        rts
+
+
+; ------------------------------------------------------------------------
+; PAGECOUNT: Return the total number of available pages in a/x.
+;
+
+PAGECOUNT:
+        lda     #<PAGES
+        ldx     #>PAGES
+        rts
+
+; ------------------------------------------------------------------------
+; MAP: Map the page in a/x into memory and return a pointer to the page in
+; a/x. The contents of the currently mapped page (if any) may be discarded
+; by the driver.
+;
+
+MAP:    sta     curpage			; Remember the new page
+
+        clc
+        adc	#>BASE
+        sta	ptr1+1
+        ldy	#$00
+        sty    	ptr1
+
+        lda	#<window
+        sta	ptr2
+        lda	#>window
+        sta	ptr2+1
+
+; Transfer one page
+
+        jsr     transfer                ; Transfer one page
+
+; Return the memory window
+
+        lda     #<window
+        ldx     #>window                ; Return the window address
+        rts
+
+; ------------------------------------------------------------------------
+; COMMIT: Commit changes in the memory window to extended storage.
+
+COMMIT: lda     curpage			; Get the current page
+        bmi     done                    ; Jump if no page mapped
+
+        clc
+        adc	#>BASE
+        sta	ptr2+1
+        ldy	#$00
+        sty    	ptr2
+
+        lda	#<window
+        sta	ptr1
+        lda	#>window
+        sta	ptr1+1
+
+; Transfer one page. Y must be zero on entry
+
+transfer:
+        ldx    	$01   			; Remember c64 control port
+        txa
+        and     #$F8           		; Bank out ROMs, I/O
+        sei
+        sta    	$01
+
+; Unroll the following loop
+
+loop:   lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+
+        bne     loop
+
+; Restore the old memory configuration, allow interrupts
+
+        stx     $01                     ; Restore the old configuration
+        cli
+
+; Done
+
+done:   rts
+
+; ------------------------------------------------------------------------
+; COPYFROM: Copy from extended into linear memory. A pointer to a structure
+; describing the request is passed in a/x.
+; The function must not return anything.
+;
+
+COPYFROM:
+        sta     ptr3
+        stx     ptr3+1                  ; Save the passed em_copy pointer
+
+        ldy     #EM_COPY_OFFS
+        lda     (ptr3),y
+        sta     ptr1
+        ldy     #EM_COPY_PAGE
+        lda     (ptr3),y
+        clc
+        adc     #>BASE
+        sta     ptr1+1                  ; From
+
+        ldy     #EM_COPY_BUF
+        lda     (ptr3),y
+        sta     ptr2
+        iny
+        lda     (ptr3),y
+        sta     ptr2+1                  ; To
+
+common: ldy     #EM_COPY_COUNT+1
+        lda     (ptr3),y                ; Get number of pages
+        beq     @L2                     ; Skip if no full pages
+        sta     tmp1
+
+; Copy full pages allowing interrupts after each page copied
+
+        ldy     #$00
+@L1:    jsr     transfer
+        inc     ptr1+1
+        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
+        beq     @L4
+        tax
+
+        lda     $01                     ; Remember c64 control port
+        pha
+        and     #$F8           		; Bank out ROMs, I/O
+        sei
+        sta    	$01
+
+; Transfer the bytes in the last page
+
+@L3:    lda	(ptr1),y
+        sta	(ptr2),y
+        iny
+        dex
+        bne     @L3
+
+; Restore the old memory configuration, allow interrupts
+
+        pla
+        sta     $01                     ; Restore the old configuration
+        cli
+
+; Done
+
+@L4:    rts          
+
+; ------------------------------------------------------------------------
+; COPYTO: Copy from linear into extended memory. A pointer to a structure
+; describing the request is passed in a/x.
+; The function must not return anything.
+;
+
+COPYTO: sta     ptr3
+        stx     ptr3+1                  ; Save the passed em_copy pointer
+
+        ldy     #EM_COPY_OFFS
+        lda     (ptr3),y
+        sta     ptr2
+        ldy     #EM_COPY_PAGE
+        lda     (ptr3),y
+        clc
+        adc     #>BASE
+        sta     ptr2+1                  ; To
+
+        ldy     #EM_COPY_BUF
+        lda     (ptr3),y
+        sta     ptr1
+        iny
+        lda     (ptr3),y
+        sta     ptr1+1                  ; From
+
+        jmp     common
+
+

libsrc/c64/c64-reu.s

@@ -123,8 +123,8 @@ PAGECOUNT:
 
 ; ------------------------------------------------------------------------
 ; MAP: Map the page in a/x into memory and return a pointer to the page in
-; a/x. The contents of the currently mapped page (if any) are assumed to be
+; a/x.  The contents of the currently mapped page (if any) may be discarded
-; dirty and must be saved into secondary storage if this is necessary.
+; by the driver.
 ;
 
 MAP:    sta     curpage
@@ -212,7 +212,7 @@ transfer:
 
         ldy 	$01       	; Save the value of the c64 control port...
         tya          	  	;
-        ora 	#$03      	; Turn on lower 3 bits to bank out ROMs, I/O.
+        and     #$F8            ; Disable ROMs and I/O.
   	sei          	  	;
         sta 	$01
         lda     REU_TRIGGER     ; Don't change $FF00