mirror of
https://github.com/cc65/cc65.git
synced 2024-12-23 19:29:37 +00:00
409 lines
9.5 KiB
ArmAsm
409 lines
9.5 KiB
ArmAsm
;
|
|
; Atari XL shadow RAM preparation routines
|
|
;
|
|
; Tasks:
|
|
; - move screen memory below load address
|
|
; - copy ROM chargen to its new place
|
|
; - copy shadow RAM contents to their destination
|
|
;
|
|
; Christian Groessler, chris@groessler.org, 2013
|
|
;
|
|
|
|
;DEBUG = 1
|
|
|
|
.ifdef __ATARIXL__
|
|
|
|
.export sramprep
|
|
|
|
.import __SRPREP_LOAD__, __SRPREPCHNK_LAST__
|
|
.import __SHADOW_RAM_LOAD__, __SHADOW_RAM_SIZE__, __SHADOW_RAM_RUN__
|
|
.import __SHADOW_RAM2_LOAD__, __SHADOW_RAM2_SIZE__, __SHADOW_RAM2_RUN__
|
|
.import __CHARGEN_START__, __CHARGEN_SIZE__
|
|
.import __STARTADDRESS__ ; needed by xlmemchk.inc
|
|
|
|
.include "zeropage.inc"
|
|
.include "atari.inc"
|
|
.include "save_area.inc"
|
|
|
|
.macro print_string text
|
|
.local start, cont
|
|
jmp cont
|
|
start: .byte text, ATEOL
|
|
cont: ldx #0 ; channel 0
|
|
lda #<start
|
|
sta ICBAL,x ; address
|
|
lda #>start
|
|
sta ICBAH,x
|
|
lda #<(cont - start)
|
|
sta ICBLL,x ; length
|
|
lda #>(cont - start)
|
|
sta ICBLH,x
|
|
lda #PUTCHR
|
|
sta ICCOM,x
|
|
jsr CIOV_org
|
|
.endmacro
|
|
|
|
; ------------------------------------------------------------------------
|
|
; EXE load chunk header
|
|
|
|
.segment "SRPREPHDR"
|
|
|
|
.word __SRPREP_LOAD__
|
|
.word __SRPREPCHNK_LAST__ - 1
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Actual code
|
|
|
|
.segment "SRPREP"
|
|
|
|
; ***** entry point *****
|
|
|
|
sramprep:
|
|
.ifdef DEBUG
|
|
print_string "entering stage #2"
|
|
.endif
|
|
|
|
; save values of modified system variables and ports
|
|
|
|
lda RAMTOP
|
|
sta RAMTOP_save
|
|
lda MEMTOP
|
|
sta MEMTOP_save
|
|
lda MEMTOP+1
|
|
sta MEMTOP_save+1
|
|
lda APPMHI
|
|
sta APPMHI_save
|
|
lda APPMHI+1
|
|
sta APPMHI_save+1
|
|
lda PORTB
|
|
sta PORTB_save
|
|
|
|
; disable BASIC
|
|
|
|
lda PORTB
|
|
ora #2
|
|
sta PORTB
|
|
|
|
.include "xlmemchk.inc" ; calculate lowest address used and new value for RAMTOP
|
|
|
|
ldx lowadr
|
|
stx MEMTOP
|
|
lda lowadr+1
|
|
sta MEMTOP+1
|
|
lda lodadr+1
|
|
sta RAMTOP
|
|
|
|
; set APPMHI to MEMLO (+ 1 for sanity)
|
|
lda MEMLO
|
|
clc
|
|
adc #1
|
|
sta APPMHI
|
|
lda MEMLO+1
|
|
adc #0
|
|
sta APPMHI+1
|
|
|
|
|
|
; issue a GRAPHICS 0 call (copied'n'pasted from TGI drivers) to move screen memory down
|
|
|
|
|
|
jsr findfreeiocb
|
|
.ifdef DEBUG ; only check in debug version, this shouldn't really happen(tm)
|
|
beq iocbok
|
|
print_string "Internal error, no free IOCB!"
|
|
jsr delay
|
|
jsr delay
|
|
jsr delay
|
|
jsr restore ; restore stuff we've changed
|
|
jmp (DOSVEC) ; abort loading
|
|
iocbok:
|
|
.endif
|
|
|
|
; reopen it in Graphics 0
|
|
lda #OPEN
|
|
sta ICCOM,x
|
|
lda #OPNIN | OPNOT
|
|
sta ICAX1,x
|
|
lda #0
|
|
sta ICAX2,x
|
|
lda #<screen_device
|
|
sta ICBAL,x
|
|
lda #>screen_device
|
|
sta ICBAH,x
|
|
lda #<screen_device_length
|
|
sta ICBLL,x
|
|
lda #>screen_device_length
|
|
sta ICBLH,x
|
|
jsr CIOV_org
|
|
bpl scrok
|
|
|
|
; shouldn't happen(tm)
|
|
print_string "Internal error, aborting..."
|
|
jsr delay
|
|
jsr delay
|
|
jsr delay
|
|
jsr restore ; restore stuff we've changed
|
|
jmp (DOSVEC) ; abort loading
|
|
|
|
|
|
scrok: ; now close it again -- we don't need it anymore
|
|
lda #CLOSE
|
|
sta ICCOM,x
|
|
jsr CIOV_org
|
|
|
|
|
|
; copy chargen to low memory, just after the next possible address beyond our loaded chunk data
|
|
|
|
.ifdef DEBUG
|
|
print_string "copy chargen to low memory"
|
|
.endif
|
|
|
|
lda #>__SRPREPCHNK_LAST__
|
|
sta ptr3+1
|
|
lda #<__SRPREPCHNK_LAST__
|
|
sta ptr3
|
|
beq cg_addr_ok
|
|
|
|
; page align the new chargen address
|
|
inc ptr3+1
|
|
lda #0
|
|
sta ptr3
|
|
|
|
cg_addr_ok:
|
|
|
|
lda ptr3+1
|
|
and #3
|
|
beq cg_addr_ok2
|
|
|
|
; align to next 1K boundary
|
|
lda ptr3+1
|
|
and #$fc
|
|
clc
|
|
adc #4
|
|
sta ptr3+1
|
|
|
|
cg_addr_ok2:
|
|
|
|
lda #<DCSORG
|
|
sta ptr1
|
|
lda #>DCSORG
|
|
sta ptr1+1
|
|
lda ptr3
|
|
sta ptr2
|
|
lda ptr3+1
|
|
pha ; needed later to set CHBAS/CHBASE
|
|
sta ptr2+1
|
|
lda #>__CHARGEN_SIZE__
|
|
sta tmp2
|
|
lda #<__CHARGEN_SIZE__
|
|
sta tmp1
|
|
jsr memcopy
|
|
|
|
.ifdef DEBUG
|
|
print_string "now setting up high memory"
|
|
.endif
|
|
|
|
; disable ROM
|
|
sei
|
|
ldx #0
|
|
stx NMIEN ; disable NMI
|
|
lda PORTB
|
|
and #$fe
|
|
tax
|
|
pla ; get temp. chargen address
|
|
sta WSYNC ; wait for horiz. retrace
|
|
stx PORTB ; now ROM is mapped out
|
|
|
|
; switch to temporary chargen
|
|
|
|
sta CHBASE
|
|
sta CHBAS
|
|
|
|
; copy shadow RAM contents to their destination (segment SHADOW_RAM)
|
|
|
|
lda #<__SHADOW_RAM_SIZE__
|
|
bne do_copy
|
|
lda #>__SHADOW_RAM_SIZE__
|
|
beq no_copy ; we have no shadow RAM contents
|
|
|
|
; ptr1 - src; ptr2 - dest; tmp1, tmp2 - len
|
|
do_copy:lda #<__SHADOW_RAM_LOAD__
|
|
sta ptr1
|
|
lda #>__SHADOW_RAM_LOAD__
|
|
sta ptr1+1
|
|
lda #<__SHADOW_RAM_RUN__
|
|
sta ptr2
|
|
lda #>__SHADOW_RAM_RUN__
|
|
sta ptr2+1
|
|
lda #<__SHADOW_RAM_SIZE__
|
|
sta tmp1
|
|
lda #>__SHADOW_RAM_SIZE__
|
|
sta tmp2
|
|
|
|
jsr memcopy
|
|
|
|
no_copy:
|
|
|
|
; copy shadow RAM #2 contents to their destination (segment SHADOW_RAM2)
|
|
|
|
lda #<__SHADOW_RAM2_SIZE__
|
|
bne do_copy2
|
|
lda #>__SHADOW_RAM2_SIZE__
|
|
beq no_copy2 ; we have no shadow RAM #2 contents
|
|
|
|
; ptr1 - src; ptr2 - dest; tmp1, tmp2 - len
|
|
do_copy2:
|
|
lda #<__SHADOW_RAM2_LOAD__
|
|
sta ptr1
|
|
lda #>__SHADOW_RAM2_LOAD__
|
|
sta ptr1+1
|
|
lda #<__SHADOW_RAM2_RUN__
|
|
sta ptr2
|
|
lda #>__SHADOW_RAM2_RUN__
|
|
sta ptr2+1
|
|
lda #<__SHADOW_RAM2_SIZE__
|
|
sta tmp1
|
|
lda #>__SHADOW_RAM2_SIZE__
|
|
sta tmp2
|
|
|
|
jsr memcopy
|
|
|
|
no_copy2:
|
|
|
|
; copy chargen to its new (final) location
|
|
|
|
lda ptr3
|
|
sta ptr1
|
|
lda ptr3+1
|
|
sta ptr1+1
|
|
lda #<__CHARGEN_START__
|
|
sta ptr2
|
|
lda #>__CHARGEN_START__
|
|
sta ptr2+1
|
|
lda #>__CHARGEN_SIZE__
|
|
sta tmp2
|
|
lda #<__CHARGEN_SIZE__
|
|
sta tmp1
|
|
jsr memcopy
|
|
|
|
; re-enable ROM
|
|
|
|
lda PORTB
|
|
ora #1
|
|
ldx #>DCSORG
|
|
sta WSYNC ; wait for horiz. retrace
|
|
sta PORTB
|
|
stx CHBASE
|
|
stx CHBAS
|
|
lda #$40
|
|
sta NMIEN ; enable VB again
|
|
cli ; and enable IRQs
|
|
|
|
.ifdef DEBUG
|
|
print_string "Stage #2 OK"
|
|
print_string "loading main chunk"
|
|
jsr delay
|
|
.endif
|
|
rts
|
|
|
|
.include "findfreeiocb.inc"
|
|
|
|
; routine taken from http://www.obelisk.demon.co.uk/6502/algorithms.html
|
|
;
|
|
; copy memory
|
|
; ptr1 - source
|
|
; ptr2 - destination
|
|
; tmp2:tmp1 - len
|
|
|
|
.proc memcopy
|
|
|
|
ldy #0
|
|
ldx tmp2
|
|
beq last
|
|
pagecp: lda (ptr1),y
|
|
sta (ptr2),y
|
|
iny
|
|
bne pagecp
|
|
inc ptr1+1
|
|
inc ptr2+1
|
|
dex
|
|
bne pagecp
|
|
last: cpy tmp1
|
|
beq done
|
|
lda (ptr1),y
|
|
sta (ptr2),y
|
|
iny
|
|
bne last
|
|
done: rts
|
|
|
|
.endproc
|
|
|
|
|
|
; clean up after a fatal error
|
|
|
|
restore:lda RAMTOP_save
|
|
sta RAMTOP
|
|
lda MEMTOP_save
|
|
sta MEMTOP
|
|
lda MEMTOP_save+1
|
|
sta MEMTOP+1
|
|
lda APPMHI_save
|
|
sta APPMHI
|
|
lda APPMHI_save+1
|
|
sta APPMHI+1
|
|
rts
|
|
|
|
; short delay
|
|
.proc delay
|
|
|
|
lda #10
|
|
@loop: jsr delay1
|
|
clc
|
|
sbc #0
|
|
bne @loop
|
|
rts
|
|
|
|
delay1: ldx #0
|
|
ldy #0
|
|
@loop: dey
|
|
bne @loop
|
|
dex
|
|
bne @loop
|
|
rts
|
|
|
|
.endproc
|
|
|
|
.ifdef DEBUG
|
|
|
|
.byte "HERE ****************** HERE ***************>>>>>>"
|
|
|
|
sramsize:
|
|
.word __SHADOW_RAM_SIZE__
|
|
|
|
.endif ; .ifdef DEBUG
|
|
|
|
screen_device: .byte "S:",0
|
|
screen_device_length = * - screen_device
|
|
|
|
.ifdef DEBUG
|
|
.byte " ** srprep ** end-->"
|
|
.endif
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Provide empty SHADOW_RAM and SHADOW_RAM2 segments in order that the
|
|
; linker is happy if the user program doesn't have these segments.
|
|
|
|
.segment "SHADOW_RAM"
|
|
.segment "SHADOW_RAM2"
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
; EXE load chunk "trailer" - sets INITAD
|
|
|
|
.segment "SRPREPTRL"
|
|
|
|
.word INITAD
|
|
.word INITAD+1
|
|
.word sramprep
|
|
|
|
.endif ; .ifdef __ATARIXL__
|