Added the vic20 georam emd.

diff --git a/doc/vic20.sgml b/doc/vic20.sgml
index 13f2a5cc83d7fbcdcc2d71128a0a7a716f8b116a..1a8f9dfefdb33525e1868de45d08180013845057 100644 (file)
--- a/doc/vic20.sgml
+++ b/doc/vic20.sgml
@@ -153,6 +153,12 @@ No graphics drivers are currently available for the VIC20.
   A driver for any RAM at $A000-$BFFF. Supports 32 256 byte pages.
   Written and contributed by Marco van den Heuvel.
 
+  <tag><tt/vic20-georam.emd (vic20_georam_emd)/</tag>
+  A driver for the Berkeley Softworks GeoRam cartridge connected by means of
+  the MasC=erade c64 cartridge adapter. The driver will determine the
+  available RAM from the connected cartridge. It supports 64KB
+  up to 2048KB of RAM.
+
 </descrip><p>
 
 

diff --git a/include/vic20.h b/include/vic20.h
index 1e8c4ceb5597881c7216f186994e7c909f20a53a..44512b3fd787c6bf0a1a023e2d3ebaae1fbf8aad 100644 (file)
--- a/include/vic20.h
+++ b/include/vic20.h
@@ -106,6 +106,7 @@ extern void vic20_ptvjoy_joy[];
 extern void vic20_stdjoy_joy[];         /* Referred to by joy_static_stddrv[] */
 
 extern void vic20_rama_emd[];
+extern void vic20_georam_emd[];
 
 /* End of vic20.h */
 #endif

diff --git a/libsrc/vic20/emd/vic20-georam.s b/libsrc/vic20/emd/vic20-georam.s
new file mode 100755 (executable)
index 0000000..a960e9a
--- /dev/null
+++ b/libsrc/vic20/emd/vic20-georam.s
@@ -0,0 +1,352 @@
+;
+; Extended memory driver for the GEORAM cartridge through the masC=erade
+; c64 cartridge adapter. Driver works without problems when statically
+; linked.
+;
+; Marco van den Heuvel, 2018-03-18
+;
+
+        .include        "zeropage.inc"
+
+        .include        "em-kernel.inc"
+        .include        "em-error.inc"
+
+
+        .macpack        generic
+        .macpack        module
+
+
+; ------------------------------------------------------------------------
+; Header. Includes jump table
+
+        module_header   _vic20_georam_emd
+
+; Driver signature
+
+        .byte   $65, $6d, $64           ; "emd"
+        .byte   EMD_API_VERSION         ; EM API version number
+
+; Library reference
+
+        .addr   $0000
+
+; Jump table
+
+        .addr   INSTALL
+        .addr   UNINSTALL
+        .addr   PAGECOUNT
+        .addr   MAP
+        .addr   USE
+        .addr   COMMIT
+        .addr   COPYFROM
+        .addr   COPYTO
+
+; ------------------------------------------------------------------------
+; Constants
+
+GR_WINDOW       = $9800                 ; Address of GEORAM window
+GR_PAGE_LO      = $9CFE                 ; Page register low
+GR_PAGE_HI      = $9CFF                 ; Page register high
+
+; ------------------------------------------------------------------------
+; Data.
+
+.data
+
+pagecount:      .res    2               ; Number of available pages
+
+.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:
+        ldx     GR_WINDOW
+        cpx     GR_WINDOW
+        bne     @notpresent
+        inc     GR_WINDOW
+        cpx     GR_WINDOW
+        beq     @notpresent
+
+        lda     #4
+        jsr     check
+        cpy     GR_WINDOW
+        beq     @has64k
+        lda     #8
+        jsr     check
+        cpy     GR_WINDOW
+        beq     @has128k
+        lda     #16
+        jsr     check
+        cpy     GR_WINDOW
+        beq     @has256k
+        lda     #32
+        jsr     check
+        cpy     GR_WINDOW
+        beq     @has512k
+        lda     #64
+        jsr     check
+        cpy     GR_WINDOW
+        beq     @has1024k
+        lda     #128
+        jsr     check
+        cpy     GR_WINDOW
+        beq     @has2048k
+        ldx     #>16384
+        bne     @setok
+
+@has64k:
+        ldx     #>256
+        bne     @setok
+@has128k:
+        ldx     #>512
+        bne     @setok
+@has256k:
+        ldx     #>1024
+        bne     @setok
+@has512k:
+        ldx     #>2048
+        bne     @setok
+@has1024k:
+        ldx     #>4096
+        bne     @setok
+@has2048k:
+        ldx     #>8192
+        bne     @setok
+
+@notpresent:
+        lda     #<EM_ERR_NO_DEVICE
+        ldx     #>EM_ERR_NO_DEVICE
+        rts
+
+@setok:
+        lda     #0
+        sta     pagecount
+        stx     pagecount+1
+        lda     #<EM_ERR_OK
+        ldx     #>EM_ERR_OK
+        rts
+
+check:
+        ldx     #0
+        stx     GR_PAGE_LO
+        stx     GR_PAGE_HI
+        ldy     GR_WINDOW
+        iny
+        sta     GR_PAGE_HI
+        sty     GR_WINDOW
+        ldx     #0
+        stx     GR_PAGE_HI
+;       rts                     ; Run into UNINSTALL instead
+
+; ------------------------------------------------------------------------
+; UNINSTALL routine. Is called before the driver is removed from memory.
+; Can do cleanup or whatever. Must not return anything.
+;
+
+UNINSTALL:
+        rts
+
+
+; ------------------------------------------------------------------------
+; PAGECOUNT: Return the total number of available pages in a/x.
+;
+
+PAGECOUNT:
+        lda     pagecount
+        ldx     pagecount+1
+        rts
+
+; ------------------------------------------------------------------------
+; USE: Tell the driver that the window is now associated with a given page.
+; The GeoRAM cartridge does not copy but actually map the window, so USE is
+; identical to MAP.
+
+USE     = MAP
+
+; ------------------------------------------------------------------------
+; 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     tmp1
+        txa
+        asl     tmp1
+        rol     a
+        asl     tmp1
+        rol     a
+
+        sta     GR_PAGE_HI
+        lda     tmp1
+        lsr     a
+        lsr     a
+        sta     GR_PAGE_LO
+
+        lda     #<GR_WINDOW
+        ldx     #>GR_WINDOW
+
+; Use the RTS from COMMIT below to save a precious byte of storage
+
+; ------------------------------------------------------------------------
+; COMMIT: Commit changes in the memory window to extended storage.
+
+COMMIT: 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:
+        jsr     setup
+
+; Setup is:
+;
+;   - ptr1 contains the struct pointer
+;   - ptr2 contains the linear memory buffer
+;   - ptr3 contains -(count-1)
+;   - tmp1 contains the low page register value
+;   - tmp2 contains the high page register value
+;   - X contains the page offset
+;   - Y contains zero
+
+        jmp     @L5
+
+@L1:    lda     GR_WINDOW,x
+        sta     (ptr2),y
+        iny
+        bne     @L2
+        inc     ptr2+1
+@L2:    inx
+        beq     @L4
+
+; Bump count and repeat
+
+@L3:    inc     ptr3
+        bne     @L1
+        inc     ptr3+1
+        bne     @L1
+        rts
+
+; Bump page register
+
+@L4:    inc     tmp1            ; Bump low page register
+        bit     tmp1            ; Check for overflow in bit 6
+        bvc     @L6             ; Jump if no overflow
+        inc     tmp2
+@L5:    lda     tmp2
+        sta     GR_PAGE_HI
+@L6:    lda     tmp1
+        sta     GR_PAGE_LO
+        jmp     @L3
+
+; ------------------------------------------------------------------------
+; 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:
+        jsr     setup
+
+; Setup is:
+;
+;   - ptr1 contains the struct pointer
+;   - ptr2 contains the linear memory buffer
+;   - ptr3 contains -(count-1)
+;   - tmp1 contains the low page register value
+;   - tmp2 contains the high page register value
+;   - X contains the page offset
+;   - Y contains zero
+
+        jmp     @L5
+
+@L1:    lda     (ptr2),y
+        sta     GR_WINDOW,x
+        iny
+        bne     @L2
+        inc     ptr2+1
+@L2:    inx
+        beq     @L4
+
+; Bump count and repeat
+
+@L3:    inc     ptr3
+        bne     @L1
+        inc     ptr3+1
+        bne     @L1
+        rts
+
+; Bump page register
+
+@L4:    inc     tmp1            ; Bump low page register
+        bit     tmp1            ; Check for overflow in bit 6
+        bvc     @L6             ; Jump if no overflow
+        inc     tmp2
+@L5:    lda     tmp2
+        sta     GR_PAGE_HI
+@L6:    lda     tmp1
+        sta     GR_PAGE_LO
+        jmp     @L3
+
+; ------------------------------------------------------------------------
+; 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: lower 6 bits in tmp1, high bits in tmp2.
+
+        ldy     #EM_COPY::PAGE+1
+        lda     (ptr1),y
+        sta     tmp2
+        dey
+        lda     (ptr1),y
+        asl     a
+        rol     tmp2
+        asl     a
+        rol     tmp2
+        lsr     a
+        lsr     a
+        sta     tmp1
+
+; Get the buffer pointer into ptr2
+
+        ldy     #EM_COPY::BUF
+        lda     (ptr1),y
+        sta     ptr2
+        iny
+        lda     (ptr1),y
+        sta     ptr2+1
+
+; Get the count, calculate -(count-1) and store it into ptr3
+
+        ldy     #EM_COPY::COUNT
+        lda     (ptr1),y
+        eor     #$FF
+        sta     ptr3
+        iny
+        lda     (ptr1),y
+        eor     #$FF
+        sta     ptr3+1
+
+; Get the page offset into X and clear Y
+
+        ldy     #EM_COPY::OFFS
+        lda     (ptr1),y
+        tax
+        ldy     #$00
+
+; Done
+
+        rts
+
+