mirror of
https://github.com/bobbimanners/emailler.git
synced 2024-11-13 20:04:37 +00:00
5218deb352
git-svn-id: http://svn.code.sf.net/p/netboot65/code@207 93682198-c243-4bdb-bd91-e943c89aac3b
294 lines
6.0 KiB
ArmAsm
294 lines
6.0 KiB
ArmAsm
|
|
.include "../inc/common.i"
|
|
|
|
print_a = $ffd2
|
|
|
|
|
|
SCREEN_RAM = $0400
|
|
COLOUR_RAM = $d800
|
|
VIC_CTRL_A = $d011
|
|
VIC_RASTER_REG = $d012
|
|
VIC_CTRL_B = $d016
|
|
VIC_MEMORY_CTRL=$d018
|
|
VIC_IRQ_FLAG = $d019
|
|
|
|
|
|
IRQ_VECTOR=$314
|
|
|
|
BORDER_COLOR = $d020
|
|
BACKGROUND_COLOR_0 = $d021
|
|
SCROLL_DELAY=4
|
|
CHARS_PER_LINE = 40
|
|
SCROLL_LINE=12
|
|
SCROLL_RAM = SCREEN_RAM+(SCROLL_LINE*CHARS_PER_LINE)
|
|
|
|
TOP_BORDER_SCAN_LINES = 50
|
|
|
|
|
|
BLACK = 0
|
|
WHITE = 1
|
|
RED = 2
|
|
CYAN = 3
|
|
PURPLE = 4
|
|
GREEN = 5
|
|
BLUE = 6
|
|
YELLOW = 7
|
|
ORANGE = 8
|
|
BROWN = 9
|
|
LIGHT_RED = 10
|
|
DARK_GRAY = 11
|
|
GRAY = 12
|
|
LIGHT_GREEN = 13
|
|
LIGHT_BLUE = 14
|
|
LIGHT_GRAY = 15
|
|
|
|
|
|
.macro wait_next_raster
|
|
lda VIC_RASTER_REG
|
|
:
|
|
cmp VIC_RASTER_REG
|
|
beq :-
|
|
.endmacro
|
|
|
|
.zeropage
|
|
temp_buff: .res 2
|
|
pptr: .res 2
|
|
|
|
.bss
|
|
|
|
|
|
.segment "STARTUP" ;this is what gets put at the start of the file on the C64
|
|
|
|
.word basicstub ; load address
|
|
|
|
basicstub:
|
|
.word @nextline
|
|
.word 2003
|
|
.byte $9e
|
|
.byte <(((init / 1000) .mod 10) + $30)
|
|
.byte <(((init / 100 ) .mod 10) + $30)
|
|
.byte <(((init / 10 ) .mod 10) + $30)
|
|
.byte <(((init ) .mod 10) + $30)
|
|
.byte 0
|
|
@nextline:
|
|
.word 0
|
|
|
|
.code
|
|
init:
|
|
|
|
|
|
lda #0
|
|
jsr clear_screen
|
|
lda #DARK_GRAY
|
|
sta BORDER_COLOR
|
|
lda #YELLOW
|
|
sta BACKGROUND_COLOR_0
|
|
|
|
|
|
|
|
sei ;disable maskable IRQs
|
|
|
|
lda #$7f
|
|
sta $dc0d ;disable timer interrupts which can be generated by the two CIA chips
|
|
sta $dd0d ;the kernal uses such an interrupt to flash the cursor and scan the keyboard, so we better
|
|
;stop it.
|
|
|
|
lda $dc0d ;by reading this two registers we negate any pending CIA irqs.
|
|
lda $dd0d ;if we don't do this, a pending CIA irq might occur after we finish setting up our irq.
|
|
;we don't want that to happen.
|
|
|
|
lda #$01 ;this is how to tell the VICII to generate a raster interrupt
|
|
sta $d01a
|
|
|
|
lda #$00 ;this is how to tell at which rasterline we want the irq to be triggered
|
|
sta VIC_RASTER_REG
|
|
|
|
ldax IRQ_VECTOR
|
|
stax old_irq
|
|
jsr set_next_irq_jump
|
|
cli ;enable maskable interrupts again
|
|
|
|
lda #23
|
|
@endless_loop:
|
|
nop
|
|
inc $ff
|
|
inc $400
|
|
tsx
|
|
stx $410
|
|
sta $411
|
|
ldy #$80
|
|
:
|
|
iny
|
|
bne :-
|
|
jmp @endless_loop
|
|
|
|
|
|
clear_screen:
|
|
|
|
ldx #$00
|
|
lda #$41
|
|
|
|
:
|
|
sta SCREEN_RAM,x
|
|
sta SCREEN_RAM+$100,x
|
|
sta SCREEN_RAM+$200,x
|
|
sta SCREEN_RAM+$300,x
|
|
sta COLOUR_RAM,x
|
|
sta COLOUR_RAM+$100,x
|
|
sta COLOUR_RAM+$200,x
|
|
sta COLOUR_RAM+$300,x
|
|
|
|
dex
|
|
bne :-
|
|
rts
|
|
|
|
set_next_irq_jump:
|
|
inc jump_counter
|
|
|
|
lda jump_counter
|
|
asl
|
|
asl
|
|
load_next_raster_entry:
|
|
tax
|
|
lda raster_jump_table,x ;bit 9 of raster to trigger on
|
|
|
|
cmp #$ff
|
|
bne not_last_entry
|
|
lda #0
|
|
sta jump_counter
|
|
jmp load_next_raster_entry
|
|
not_last_entry:
|
|
ora #$18 ;turn on bits 3 & 4
|
|
sta VIC_CTRL_A
|
|
lda raster_jump_table+1,x ;bits 0..7 of raster to trigger on
|
|
sta VIC_RASTER_REG
|
|
lda raster_jump_table+2,x ;LSB of IRQ handler
|
|
sta IRQ_VECTOR
|
|
lda raster_jump_table+3,x ;LSB of IRQ handler
|
|
sta IRQ_VECTOR+1
|
|
rts
|
|
|
|
exit_from_irq:
|
|
jsr set_next_irq_jump
|
|
jmp_to_original_irq_handler:
|
|
lda #$ff ;this is the orthodox and safe way of clearing the interrupt condition of the VICII.
|
|
sta VIC_IRQ_FLAG;if you don't do this the interrupt condition will be present all the time and you end
|
|
;up having the CPU running the interrupt code all the time, as when it exists the
|
|
;interrupt, the interrupt request from the VICII will be there again regardless of the
|
|
;rasterline counter.
|
|
|
|
old_irq = * + 1 ; Placeholder for self-modifying code
|
|
jmp $ffff
|
|
|
|
raster_irq:
|
|
|
|
ldax #synchronised_irq
|
|
stax IRQ_VECTOR
|
|
nop ; waste at least 12 cycles
|
|
nop ; (up to 64 cycles delay allowed here)
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
inc VIC_RASTER_REG ; At this stage, we have already moved to the next line
|
|
lda #1
|
|
sta VIC_IRQ_FLAG ; acknowledge the first raster interrupt
|
|
cli ; enable interrupts (the second interrupt can now occur)
|
|
ldy #9
|
|
dey
|
|
bne *-1 ; delay
|
|
nop ; The second interrupt will occur while executing these
|
|
nop ; two-cycle instructions.
|
|
nop
|
|
nop
|
|
nop
|
|
|
|
jmp jmp_to_original_irq_handler
|
|
|
|
synchronised_irq:
|
|
|
|
ldx VIC_RASTER_REG
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
bit $24 ; 6569, 63 cycles/line
|
|
|
|
cpx VIC_RASTER_REG ; The comparison cycle is executed CYCLES or CYCLES+1 cycles
|
|
; after the interrupt has occurred.
|
|
beq :+ ; Delay by one cycle if $d012 hadn't changed.
|
|
; Now exactly CYCLES+3 cycles have passed since the interrupt
|
|
:
|
|
|
|
;now got a stable raster
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
nop
|
|
inc BORDER_COLOR
|
|
inc BACKGROUND_COLOR_0
|
|
|
|
ldx #20
|
|
@loop:
|
|
wait_next_raster
|
|
dex
|
|
bne @loop
|
|
dec BORDER_COLOR
|
|
dec BACKGROUND_COLOR_0
|
|
|
|
|
|
jmp exit_from_irq
|
|
|
|
|
|
|
|
.data
|
|
|
|
raster_jump_table:
|
|
;format:
|
|
;offset meaning
|
|
; $00 BIT 9 OF RASTER TO TRIGGER ON ($00 if bit 8 =0 , $80 if bit 8 =1)
|
|
; $01 BITS 0..7 OF RASTER TO TRIGGER ON
|
|
; $02 LSB OF ROUTINE TO JUMP TO
|
|
; $03 MSB OF ROUTINE TO JUMP TO
|
|
;table needs to end with a single byte $ff
|
|
;table needs to be sorted by scanlines
|
|
; .byte $0,$01
|
|
; .word scroll_text_irq
|
|
.byte $0,$81
|
|
.word raster_irq
|
|
|
|
; .byte $0,$80
|
|
; .word raster_irq
|
|
.byte $ff ;end of list
|
|
|
|
jump_counter: .byte 0
|
|
|
|
|
|
|
|
|
|
|
|
;-- LICENSE FOR raster.s --
|
|
; The contents of this file are subject to the Mozilla Public License
|
|
; Version 1.1 (the "License"); you may not use this file except in
|
|
; compliance with the License. You may obtain a copy of the License at
|
|
; http://www.mozilla.org/MPL/
|
|
;
|
|
; Software distributed under the License is distributed on an "AS IS"
|
|
; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
|
|
; License for the specific language governing rights and limitations
|
|
; under the License.
|
|
;
|
|
; The Original Code is ip65.
|
|
;
|
|
; The Initial Developer of the Original Code is Jonno Downes,
|
|
; jonno@jamtronix.com.
|
|
; Portions created by the Initial Developer are Copyright (C) 2009
|
|
; Jonno Downes. All Rights Reserved.
|
|
; -- LICENSE END --
|