arch-example.a

;ACME 0.96.2
; architecture-specific stuff for FIXME-WHATEVER

; config
	MAKE_BASIC_HEADER	= 0	; set to nonzero to create a CBM-style basic header
	ALLOW_CURSOR		= 0	; set to nonzero to allow cursor navigation (currently needs petscii codes)
	ALLOW_KEYPAD		= 1	; set to nonzero to allow keypad navigation
	INCLUDE_CHARSET		= 0	; set to nonzero to include own charset
	KEYBOARD_IS_PETSCII	= 0	; set to nonzero if "sys_getin" function returns petscii codes
	LINE_LENGTH		= 80	; system's screen width (needed for location title and word wrap)
	sys_NEWLINE		= 10	; system's newline character (probably 10 or 13)

; libraries
	;!src <>

; constants
	controlcode_HOME	= petscii_HOME
	controlcode_CLEAR	= petscii_CLEAR
	controlcode_REVSON	= petscii_REVSON
	controlcode_REVSOFF	= petscii_REVSOFF
	controlcode_UP		= petscii_UP
	controlcode_DOWN	= petscii_DOWN
	controlcode_LEFT	= petscii_LEFT
	controlcode_RIGHT	= petscii_RIGHT

; zero page
!addr	runptr		= $00	; 16bit, points to next bytecode instruction (also used for inline text output and scanning of usage list)
!addr	recursion_depth	= $02	; 8bit, counts recursion levels (okay, this need not really be in zp)
!addr	z_quote_mode	= $03	; 8bit - if your system does not know any "quote mode", just consider this to be a write-only variable)

; system area
!addr	is_PAL		= $0815	; zero for NTSC, nonzero for PAL (needed so "delay" can convert seconds to video frames)

; other
	load_addr	= $1000	; program counter at start of assembly

; kernal
!addr	sys_chrout	= $ffd2	; system function to output a character - MUST PRESERVE A/X/Y!
!addr	sys_getin	= $ffe4	; system function to read a character from keyboard

; color codes:
; (names are from C64 colors, but architecture can change values in 0..f range)
	color_BLACK	= colorbase + $0
	color_WHITE	= colorbase + $1
	color_RED	= colorbase + $2
	color_CYAN	= colorbase + $3
	color_PURPLE	= colorbase + $4
	color_GREEN	= colorbase + $5
	color_BLUE	= colorbase + $6
	color_YELLOW	= colorbase + $7
	color_ORANGE	= colorbase + $8
	color_BROWN	= colorbase + $9
	color_LRED	= colorbase + $a
	color_GRAY1	= colorbase + $b
	color_GRAY2	= colorbase + $c
	color_LGREEN	= colorbase + $d
	color_LBLUE	= colorbase + $e
	color_GRAY3	= colorbase + $f

; code macros

; if architecture uses MAKE_BASIC_HEADER, this macro will be called just before
; generating the SYS instruction, so you can insert other instructions
!macro arch_basicstuff {
		!by $99, $22, $58, $22, $3a	; print"x":
}

; if architecture does NOT use MAKE_BASIC_HEADER, this macro will be called to
; create your own program header. enter the program with a jump to "entry".
!macro arch_header {
		jsr entry
		jmp $4711	; return to shell
}

; this is used to delay execution
; if X is zero on call, just wait for vblank
!macro arch_wait_X_frames {
}

; this is used early on so machine can be initialised
; (memory configuration, find out whether PAL/NTSC, fade to black, ...)
!macro arch_init {
}

; this is used a bit later to init output system (init video chip, setup
; charset, clear screen, enable display)
!macro arch_output_init {
}

; set screen colors:
; set border color to (color_border & 0xf)
; set background color to (color_background & 0xf)
; ...and if system does not support changing text color during game, you should
; set global text color to (color_std & 0xf)
!macro arch_set_colors {
}

; this is used when entering a new location, just after clearing the screen.
; it should paint a reverse title bar on the screen
!macro arch_invert_title {
}

; change text color to that given in A.
; do not clobber X or Y! if you need one or both of them, restore their old contents (see arch264.a)
!macro arch_set_text_color_A {
		and #%....####	; keep color, remove base code
		;sta whereever_your_system_stores_attribute_of_future_chars	; and store
}

; all macros above are inserted directly into code, without JSR/RTS.
; if your code needs special routines to call and/or tables, put those here:
!macro arch_bulk {
my_special_routine1
		sed
		tax
		lda my_lookup_table, x
		tay
		rts

my_lookup_table	!by 1, 2, 3
}

; this is called at end of assembly so you can check for memory limits
!macro arch_check_memlimit {
	!if * >= $abcd {	!error "Reached kernal area, overwriting it! Shorten program or kernal!" }
}