Overhaul the template.

- DATA and RODATA segments added to computer.cfg
 - RAM memory configuration now starts at  to not overwrite the cpu stack
 - hardware.inc added to handle hardware related constants
 - constants removed from via.s
 - constants removed from serial.s
 - serial_delay from serial.s is now dynamic, dependant on CPU_HZ and baud rate
 - serial_baud_* functions added to setup 19200 and 9600 baud
 - mem_copy.s added. data copy functions are to be implemented here
 - copy_data (mem_copy.s) implemented to copy the DATA segment from ROM to RAM
 - propper system setup in main.s
 - Makefile now generates a .map file with the memory map information

src/main.s

@@ -1,40 +1,72 @@
-.import serial_setup
-.import serial_print_char
+.import serial_setup, serial_print_char, serial_recv_char
+.import copy_data
 
-.segment "ZEROPAGE"
+; ---------------
+;       ZP
+; ---------------
+.zeropage
 ; Zero-page variables ($0000 - $00ff)
 
-.segment "BSS"
-; RAM variables ($0100 - $7fff)
+; ---------------
+;       BSS
+; ---------------
+.bss
+; RAM variables ($0200 - $7fff)
 
-.segment "CODE"
+; ---------------
+;      DATA
+; ---------------
+.data
+; Initialized RAM variables ($0200 - $7fff)
+
+; ---------------
+;      CODE
+; ---------------
+.code
 ; Actual program code ($c000 - $fff9)
+reset:                              ; Program starts here
+; System setup
+    sei                             ; disable interrupts while setting things up
+    cld                             ; clear BCD mode flag (undefined on NMOS 6502, auto cleared on 65C02)
+    ldx #$ff
+    txs                             ; Reset stack pointer
 
-reset:  ; Program starts here
-    jsr serial_setup
+    jsr copy_data                   ; copy data variables from ROM to RAM
 
+    jsr serial_setup                ; setup serial interface (65C51N). 19200 baud set as default
+
+print_hello_world:
     ldx #0
-hello_world_loop:
-    lda str_hello_world,x   ; get char
-    beq hello_world_end     ; IF char is 0, done
-    jsr serial_print_char   ; send char to console
-    inx                     ; increment x (next char)
-    jmp hello_world_loop
-hello_world_end:
-    jmp hello_world_end
+@loop:
+    lda str_hello_world,x           ; get char
+    beq @end                        ; IF char is 0, done
+    jsr serial_print_char           ; send char to console
+    inx                             ; increment x (next char)
+    jmp @loop
+@end:
+    jmp @end
 
 
-irq:    ; IRQ Handler
-    rti ; Do nothing
+irq_handler:                        ; IRQ Handler
+    rti                             ; Do nothing
 
-nmi:    ; NMI handler
-    rti ; Do nothing
+nmi_handler:                        ; NMI handler
+    rti                             ; Do nothing
 
-str_hello_world:
-.asciiz "Hello, World!"
 
+; ---------------
+;     RODATA
+; ---------------
+.rodata
+; Constants
+str_hello_world: .asciiz "Hello, World!"
+
+
+; ---------------
+;     VECTORS
+; ---------------
 .segment "VECTORS"
 ; NMI, RESET and IRQ vectors
-.word nmi
+.word nmi_handler
 .word reset
-.word irq
+.word irq_handler