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Completed the REU driver

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git-svn-id: svn://svn.cc65.org/cc65/trunk@1683 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2002-12-01 18:07:06 +00:00
parent 0c38839e79
commit ef166c1fa8
1 changed files with 54 additions and 52 deletions
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106
libsrc/c64/c64-reu.s
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@ -29,7 +29,7 @@
.word DEINSTALL
.word PAGECOUNT
.word MAP
.word MAPCLEAN
.word COMMIT
.word COPYFROM
.word COPYTO
@ -43,6 +43,7 @@ REU_REUADDR = $DF04 ; REU base address register
REU_COUNT = $DF07 ; Transfer count register
REU_IRQMASK = $DF09 ; IRQ mask register
REU_CONTROL = $DF0A ; Control register
REU_TRIGGER = $FF00 ; REU command trigger
OP_COPYFROM = $ED
OP_COPYTO = $EC
@ -65,8 +66,6 @@ reu_params: .word $0000 ; Host address, lo, hi
.byte $00 ; Interrupt mask reg.
.byte $00 ; Adress control reg.
.code
; ------------------------------------------------------------------------
@ -128,40 +127,25 @@ PAGECOUNT:
; dirty and must be saved into secondary storage if this is necessary.
;
MAP: ldy curpage+1 ; Do we have a page mapped?
bmi MAPCLEAN ; Jump if no page mapped
MAP: sta curpage
stx curpage+1 ; Remember the new page
ldy #<window
sty REU_C64ADDR
ldy #>window
sty REU_C64ADDR+1
ldy #OP_COPYFROM
jsr common ; Copy the window
ldy #0
sty REU_COUNT+0
sty REU_REUADDR+0
ldy curpage
sty REU_REUADDR+1
ldy curpage+1
sty REU_REUADDR+2
ldy #1
sty REU_COUNT+1 ; Move 256 bytes
ldy #OP_COPYTO
pha
jsr Transfer ; Transfer 256 bytes into REU
pla
; Run straight into MAPCLEAN
lda #<window
ldx #>window ; Return the window address
done: rts
; ------------------------------------------------------------------------
; MAPCLEAN: 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 clean, so if this is an advantage for the driver, the current contents
; may be discarded.
; COMMIT: Commit changes in the memory window to extended storage.
MAPCLEAN:
sta curpage
stx curpage+1 ; Remember the new page
COMMIT: lda curpage
ldx curpage+1 ; Do we have a page mapped?
bmi done ; Jump if no page mapped
ldy #OP_COPYTO
common: sty tmp1
ldy #<window
sty REU_C64ADDR
@ -176,12 +160,7 @@ MAPCLEAN:
ldy #1
sty REU_COUNT+1 ; Move 256 bytes
ldy #OP_COPYFROM
jsr Transfer ; Transfer 256 bytes into REU
lda #<window
ldx #>window ; Return the window address
rts
bne transfer1 ; Transfer 256 bytes into REU
; ------------------------------------------------------------------------
; COPYFROM: Copy from extended into linear memory. A pointer to a structure
@ -190,7 +169,8 @@ MAPCLEAN:
;
COPYFROM:
ldy #OP_COPYFROM
.byte $2C
; ------------------------------------------------------------------------
; COPYTO: Copy from linear into extended memory. A pointer to a structure
@ -199,24 +179,46 @@ COPYFROM:
;
COPYTO:
lda #0
tax
rts
ldy #OP_COPYTO
sty tmp1
; Remember the passed pointer
sta ptr1
stx ptr1+1 ; Save the pointer
; The structure passed to the functions has the same layout as the registers
; of the Commodore REU, so register programming is easy.
ldy #7-1
@L1: lda (ptr1),y
sta REU_C64ADDR,y
dey
bpl @L1
; Invalidate the page in the memory window
sty curpage+1 ; Y = $FF
; Reload the REU command and start the transfer
transfer1:
ldy tmp1
; ---------------------------------------------------------------------------
; Transfer subroutine for the REU. Expects command in Y.
Transfer:
sty $df01 ; Issue command
transfer:
sty REU_COMMAND ; Issue command
sei ; Save the value of the
ldy $01 ; the c64 control port
tya ; and turn on lower 3 bits
ora #$03 ; to bank out ROMs, I/O.
ldy $01 ; Save the value of the c64 control port...
tya ;
ora #$03 ; Turn on lower 3 bits to bank out ROMs, I/O.
sei ;
sta $01
lda $ff00
sta $ff00 ; Now start transfer...
lda REU_TRIGGER ; Don't change $FF00
sta REU_TRIGGER ; Start the transfer...
sty $01 ; Restore the old configuration
sty $01 ; Restore the old configuration
cli
rts