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Remove screen flicker while mapping ROM out and in.

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Some cleanups.
This commit is contained in:
Christian Groessler 2013-09-04 22:10:36 +02:00
parent 1e8e998991
commit 4a0bdf871b
1 changed files with 50 additions and 15 deletions
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65
libsrc/atari/shadow_ram_prepare.s
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@ -43,7 +43,7 @@ cont: ldx #0 ; channel 0
.endmacro
; ------------------------------------------------------------------------
; Chunk header
; EXE load chunk header
.segment "SRPREPHDR"
@ -74,13 +74,13 @@ sramprep:
sta APPMHI_save+1
lda PORTB
sta PORTB_save
lda CIOV ; zero-page wrapper
lda CIOV ; zero-page wrapper
sta ZP_CIOV_save
lda CIOV+1
sta ZP_CIOV_save+1
lda CIOV+2
sta ZP_CIOV_save+2
lda SIOV ; zero-page wrapper
lda SIOV ; zero-page wrapper
sta ZP_SIOV_save
lda SIOV+1
sta ZP_SIOV_save+1
@ -112,11 +112,11 @@ sramprep:
sta APPMHI+1
; ... issue a GRAPHICS 0 call (copied'n'pasted from TGI drivers)
; 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 happen normally(tm)
.ifdef DEBUG ; only check in debug version, this shouldn't really happen(tm)
beq iocbok
print_string "Internal error, no free IOCB!"
jsr delay
@ -164,7 +164,6 @@ scrok: ; now close it again -- we don't need it anymore
.ifdef DEBUG
print_string "copy chargen to low memory"
print_string "set up high memory"
.endif
lda #>(__SRPREP_LOAD__ + __SRPREP_SIZE__ + __SHADOW_RAM_SIZE__)
@ -179,6 +178,20 @@ scrok: ; now close it again -- we don't need it anymore
sta ptr3
cg_addr_ok:
lda ptr3+1
and #3
beq cg_addr_ok2
; align to next 1K boundary
lda ptr3+1
and #$fc
clc
adc #4
sta ptr3+1
cg_addr_ok2:
lda #<DCSORG
sta ptr1
lda #>DCSORG
@ -186,29 +199,40 @@ cg_addr_ok:
lda ptr3
sta ptr2
lda ptr3+1
pha ; needed later to set CHBAS/CHBASE
sta ptr2+1
lda #>__CHARGEN_SIZE__
sta tmp2
lda #<__CHARGEN_SIZE__
sta tmp2+1
sta tmp1
jsr memcopy
; TODO: switch to this temp. chargen
.ifdef DEBUG
print_string "now setting up high memory"
.endif
; disable ROMs
; disable ROM
sei
ldx #0
stx NMIEN ; disable NMI
stx NMIEN ; disable NMI
lda PORTB
and #$fe
sta PORTB ; now ROM is mapped out
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
lda #<__SHADOW_RAM_SIZE__
bne do_copy
lda #>__SHADOW_RAM_SIZE__
beq no_copy ; we have no shadow RAM contents
beq no_copy ; we have no shadow RAM contents
; ptr1 - src; ptr2 - dest; tmp1, tmp2 - len
do_copy:lda #<__SHADOW_RAM_LOAD__
@ -248,21 +272,26 @@ no_copy:
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"
; my 6502 fu is rusty, so I took a routine from the internet (http://www.obelisk.demon.co.uk/6502/algorithms.html)
; routine taken from http://www.obelisk.demon.co.uk/6502/algorithms.html
;
; copy memory
; ptr1 - source
; ptr2 - destination
@ -307,6 +336,8 @@ restore:lda RAMTOP_save
rts
.ifdef DEBUG
.byte "HERE ****************** HERE ***************>>>>>>"
sramsize:
@ -332,10 +363,14 @@ loop: dey
.endproc
.endif ; .ifdef DEBUG
screen_device: .byte "S:",0
screen_device_length = * - screen_device
.ifdef DEBUG
.byte " ** srprep ** end-->"
.endif
; ------------------------------------------------------------------------
; Provide an empty SHADOW_RAM segment in order that the linker is happy
@ -345,7 +380,7 @@ screen_device_length = * - screen_device
; ------------------------------------------------------------------------
; Chunk "trailer" - sets INITAD
; EXE load chunk "trailer" - sets INITAD
.segment "SRPREPTRL"