New upload module

git-svn-id: svn://svn.cc65.org/cc65/trunk@3254 b7a2c559-68d2-44c3-8de9-860c34a00d81

libsrc/lynx/Makefile

@@ -35,7 +35,8 @@
 
 OBJS =	crt0.o          \
         eeprom.o        \
-        framerate.o
+        framerate.o     \
+        upload.o        
 
 #--------------------------------------------------------------------------
 # Drivers

libsrc/lynx/upload.s

@@ -0,0 +1,155 @@
+; ***
+; 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
+