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More P500 support

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git-svn-id: svn://svn.cc65.org/cc65/trunk@920 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz
2001-09-14 14:37:08 +00:00
parent c4a49faf48
commit e1a9115fd4
8 changed files with 220 additions and 86 deletions
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95
libsrc/cbm510/crt0.s
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@@ -176,34 +176,6 @@ L3: lda (ptr1),y
iny
bne L3
; Reprogram the VIC so that the text screen is at $F800 in the execution bank
; Place the VIC video RAM into bank 0
; CA (STATVID) = 0
ldy #tpiCtrlReg
lda (tpi1),y
and #$CF
ora #$20
sta (tpi1),y
; Set bit 14/15 of the VIC address range to the high bits of VIDEO_RAM
; PC6/PC7 (VICBANKSEL 0/1) = 11
ldy #tpiPortC
lda (tpi2),y
and #$3F
ora #((>VIDEO_RAM) & $C0)
sta (tpi2),y
; Set bits 10-13 of the VIC address range to address F800
ldy #VIC_VIDEO_ADR
lda (vic),y
and #$0F
ora #(((>VIDEO_RAM) & $3F) << 2)
sta (vic),y
; Set the indirect segment to bank we're executing in
lda ExecReg
@@ -263,10 +235,52 @@ 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.
; Clear the video memory
; 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:
lda #$0F ; We need access to the system bank
sta IndReg
; Place the VIC video RAM into bank 0
; CA (STATVID) = 0
ldy #tpiCtrlReg
lda (tpi1),y
sta vidsave+0
and #$CF
ora #$20
sta (tpi1),y
; Set bit 14/15 of the VIC address range to the high bits of VIDEO_RAM
; PC6/PC7 (VICBANKSEL 0/1) = 11
ldy #tpiPortC
lda (tpi2),y
sta vidsave+1
and #$3F
ora #((>VIDEO_RAM) & $C0)
sta (tpi2),y
; Set bits 10-13 of the VIC address range to address F800
ldy #VIC_VIDEO_ADR
lda (vic),y
sta vidsave+2
and #$0F
ora #(((>VIDEO_RAM) & $3F) << 2)
sta (vic),y
; Switch back to the execution bank
lda ExecReg
sta IndReg
; Call module constructors
jsr initlib
@@ -359,6 +373,25 @@ Start:
_exit: jsr donelib ; Run module destructors
; We need access to the system bank now
lda #$0F
sta IndReg
; Switch back the video to the system bank
ldy #tpiCtrlReg
lda vidsave+0
sta (tpi1),y
ldy #tpiPortC
lda vidsave+1
sta (tpi2),y
ldy #VIC_VIDEO_ADR
lda vidsave+2
sta (vic),y
; Clear the start of the zero page, since it will be interpreted as a
; (garbage) BASIC program otherwise. This is also the default entry for
; the break vector.
@@ -373,8 +406,6 @@ Clear: sta $02,x
; Setup the welcome code at the stack bottom in the system bank. Use
; the F4/F5 vector to access the system bank
lda #$0F
sta IndReg
ldy #$00
sty $F4
iny
@@ -445,6 +476,6 @@ k_settim:
.data
spsave: .res 1
vidsave:.res 3