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We need to have the character data in the VIC bank to make sprites work.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@954 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2001-09-20 09:53:12 +00:00
parent afb63ff31c
commit 9d926289e1
1 changed files with 59 additions and 25 deletions
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84
libsrc/cbm510/crt0.s
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@ -5,9 +5,9 @@
;
.export _exit
.import _clrscr, initlib, donelib
.import _clrscr, initlib, donelib
.import push0, _main
.import __VIDRAM_START__
.import __CHARRAM_START__, __CHARRAM_SIZE__, __VIDRAM_START__
.import __BSS_RUN__, __BSS_SIZE__
.import irq, nmi
.import k_irq, k_nmi, k_plot, k_udtim, k_scnkey
@ -237,54 +237,88 @@ Z4:
; This code is in page 2, so we may now start calling subroutines safely,
; since the code we execute is no longer in the stack page.
; Copy the character rom from the system bank into the execution bank
lda #<$C000
sta ptr1
lda #>$C000
sta ptr1+1
lda #<__CHARRAM_START__
sta ptr2
lda #>__CHARRAM_START__
sta ptr2+1
lda #>__CHARRAM_SIZE__ ; 16 * 256 bytes to copy
sta tmp1
ldy #$00
ccopy: lda #$0F
sta IndReg ; Access the system bank
ccopy1: lda (ptr1),y
sta __VIDRAM_START__,y
iny
bne ccopy1
lda ExecReg
sta IndReg
ccopy2: lda __VIDRAM_START__,y
sta (ptr2),y
iny
bne ccopy2
inc ptr1+1
inc ptr2+1 ; Bump high pointer bytes
dec tmp1
bne ccopy
; Clear the video memory. We will do this before switching the video to bank 0
; to avoid garbage when doing so.
jsr _clrscr
; Reprogram the VIC so that the text screen is at $F800 in the execution bank
; This is done in three steps:
; Reprogram the VIC so that the text screen and the character ROM is in the
; execution bank. This is done in three steps:
lda #$0F ; We need access to the system bank
sta IndReg
sta IndReg
; Place the VIC video RAM into bank 0
; CA (STATVID) = 0
; CA (STATVID) = 0
; CB (VICDOTSEL) = 0
ldy #tpiCtrlReg
lda (tpi1),y
sta vidsave+0
and #$CF
ora #$20
sta (tpi1),y
ldy #tpiCtrlReg
lda (tpi1),y
sta vidsave+0
and #%00001111
ora #%10100000
sta (tpi1),y
; Set bit 14/15 of the VIC address range to the high bits of __VIDRAM_START__
; PC6/PC7 (VICBANKSEL 0/1) = 11
ldy #tpiPortC
lda (tpi2),y
sta vidsave+1
and #$3F
ldy #tpiPortC
lda (tpi2),y
sta vidsave+1
and #$3F
ora #<((>__VIDRAM_START__) & $C0)
sta (tpi2),y
sta (tpi2),y
; Set bits 10-13 of the VIC address range to address F800
; Set the VIC base address register to the addresses of the video and
; character RAM.
ldy #VIC_VIDEO_ADR
lda (vic),y
sta vidsave+2
and #$0F
ora #<(((>__VIDRAM_START__) << 2) & $F0)
sta (vic),y
lda (vic),y
sta vidsave+2
and #$01
ora #<(((__VIDRAM_START__ >> 6) & $F0) | ((__CHARRAM_START__ >> 10) & $0E) | $02)
; and #$0F
; ora #<(((>__VIDRAM_START__) << 2) & $F0)
sta (vic),y
; Switch back to the execution bank
lda ExecReg
sta IndReg
sta IndReg
; Call module constructors
jsr initlib
jsr initlib
; Create the (empty) command line for the program