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@include %bootstrap
@include %std_mem
@include %std_term
; Constants
@data text_buffer_size 2048
; Global variable pointers
; 0xE800 - 0xEFFF: sprite buffer space that is unused in this program
@data cursor_p 0xE800
@data title_string " »» ATK16 monitor v0.1 »»"
@data subtitle_string " Run [help] for a list of commands"
@label main
; initialize global variables
; BEGIN cursor_p := text_mem
ldi cursor_p RA
ldr RA RA
ldi vt_text_mem RB
ldr RB RB
str RB RA
; END
; use memset to clear the text buffer
; BEGIN memset(text_mem, 0, text_buffer_size)
ldi vt_text_mem RA ; RA := text buffer address pointer
ldr RA RA ; RA := text buffer address
ldi text_buffer_size RB ; RB := pointer to text_buffer_size
ldr RB RB ; RB := text_buffer_size
ldi 0 RC ; RC := 0
calli memset
; END
set_graphics_mode gr_text_mode
calli newline
; BEGIN put_string(title_string)
ldi title_string RA
calli put_string
; END
calli newline
; BEGIN put_string(subtitle_string)
ldi subtitle_string RA
calli put_string
; END
; loop forever
@label loop
jpi loop
@label newline
; move cursor to the beginning of the next line
; parameters: none
; returns: none
stack_stash RA RB
ldi cursor_p RA
ldr RA RA
ldr RA RB
slri RB 6 RB ; cursor = cursor / 64
addi RB 1 RB ; cursor = cursor + 1
slli RB 6 RB ; cursor = cursor * 64
str RB RA
stack_restore RA RB
return
@label put_char
; put a character at the current cursor position
; parameters: RA = character to put
; returns: none
stack_stash RB RC
ldi cursor_p RB
ldr RB RB
ldr RB RC
str RA RC
inc RC
str RC RB
stack_restore RB RC
return
@label put_string
; put a string at the current cursor position
; parameters: RA = string_p
; returns: none
stack_stash RA RB RC
ldr RA RB ; RB := string length
addi RA 1 RC ; RC := pointer to first character
@label put_string_loop
subi RB 0 RB ; exit if RB has been decremented to 0
bri zero put_string_done ; i.e. no more characters to put
ldr RC RA ; RA := character to put
calli put_char
inc RC
subi RB 1 RB
jpi put_string_loop
@label put_string_done
stack_restore RA RB RC
return
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