mirror of
https://github.com/cc65/cc65.git
synced 2024-12-23 04:30:10 +00:00
c2f003449d
git-svn-id: svn://svn.cc65.org/cc65/trunk@3254 b7a2c559-68d2-44c3-8de9-860c34a00d81
156 lines
3.2 KiB
ArmAsm
156 lines
3.2 KiB
ArmAsm
; ***
|
|
; CC65 Lynx Library
|
|
;
|
|
; Originally by Bastian Schick
|
|
; http://www.geocities.com/SiliconValley/Byte/4242/lynx/
|
|
;
|
|
; Ported to cc65 (http://www.cc65.org) by
|
|
; Shawn Jefferson, June 2004
|
|
;
|
|
; ***
|
|
;
|
|
; void install_uploader(unsigned char divider);
|
|
;
|
|
; Installs an interrupt handler that hooks the comlynx rx/tx interrupts to
|
|
; allow upload of code to the lynx from another computer via the comlynx
|
|
; cable. divider values are in lynx.h
|
|
;
|
|
; Loader is installed under the mikey chip at $FE00.
|
|
;
|
|
|
|
.include "lynx.inc"
|
|
.export _lynx_install_uploader
|
|
.import _install_irq
|
|
.import popa, pusha
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.segment "EXTZP": zeropage
|
|
|
|
load_len: .res 2
|
|
load_ptr: .res 2
|
|
load_ptr2: .res 2
|
|
|
|
|
|
.code
|
|
|
|
; ------------------------------------------------------------------------
|
|
; The following code will get moved to $FE00 when installing the uploader.
|
|
|
|
.proc Loader
|
|
|
|
.org $fe00
|
|
|
|
run: ldy #4
|
|
loop0: jsr read_byte
|
|
sta load_len-1,y
|
|
dey
|
|
bne loop0 ; get destination and length
|
|
tax ; lowbyte of length
|
|
|
|
lda load_ptr
|
|
sta load_ptr2
|
|
lda load_ptr+1
|
|
sta load_ptr2+1
|
|
|
|
loop1: inx
|
|
bne cont1
|
|
inc load_len+1
|
|
bne cont1
|
|
jmp (load_ptr)
|
|
|
|
cont1: jsr read_byte
|
|
sta (load_ptr2),y
|
|
sta PALETTE ; feedback ;-)
|
|
iny
|
|
bne loop1
|
|
inc load_ptr2+1
|
|
bra loop1
|
|
|
|
read_byte:
|
|
bit SERCTL
|
|
bvc read_byte
|
|
lda SERDAT
|
|
rts
|
|
|
|
.reloc
|
|
|
|
.endproc
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.code
|
|
|
|
_lynx_install_uploader:
|
|
|
|
ldx #.sizeof(Loader)-1 ; put Loader in the right place
|
|
loop: lda Loader,x ; x is length of loader
|
|
sta Loader::run,x
|
|
dex
|
|
bpl loop
|
|
|
|
;
|
|
; install serial-irq vector
|
|
;
|
|
lda #4
|
|
jsr pusha
|
|
lda #<UpLoader
|
|
ldx #>UpLoader
|
|
jsr _install_irq ; set vector
|
|
;
|
|
; set baudrate
|
|
;
|
|
jsr popa ; get divider
|
|
sta $fd10
|
|
lda #%00011000 ; Baudrate = 1MHz/16/(divider+1)
|
|
sta $fd11
|
|
;
|
|
; set ComLynx parameters
|
|
;
|
|
lda #%00011101 ; even par
|
|
sta SERCTL ; set 8E1
|
|
;
|
|
; clear Rx-buffer
|
|
;
|
|
clear: bit SERCTL
|
|
bvc ok0
|
|
ldx SERDAT
|
|
bra clear
|
|
;
|
|
; enable Rx-interrupt
|
|
;
|
|
ok0: ora #$40
|
|
sta SERCTL
|
|
rts
|
|
|
|
|
|
; ------------------------------------------------------------------------
|
|
; Rx-IRQ-handler
|
|
|
|
UpLoader:
|
|
lda SERDAT ; wait for the start sequence
|
|
bit flag ; already seen $81 ?
|
|
bpl again ; >= 0 => no
|
|
cmp #$50 ; "P" ?
|
|
bne again ; not correct, so clear flag
|
|
jmp Loader::run
|
|
|
|
again: stz flag
|
|
cmp #$81
|
|
bne exit
|
|
sta flag
|
|
;
|
|
; last action : clear interrupt
|
|
;
|
|
exit: lda #$10
|
|
sta INTRST
|
|
rts
|
|
|
|
|
|
.data
|
|
|
|
flag: .byte 0
|
|
|