Working character output, non working return to home

This commit is contained in:
Daniele Verducci su MatissePenguin 2021-01-25 08:46:01 +01:00
parent 9de4753984
commit 154e4dc10c
3 changed files with 71 additions and 38 deletions

View File

@ -9,8 +9,8 @@
.equ LINE_COLUMNS = 52 ; number of columns (characters or chunks) per line
; Draws character in register A to the screen at current coords (Y)
; @param A (r0) ascii code to display
; @modifies r0 (A), r1, r2, r3, r16 (HIGH_ACCUM), Y, Z
; @param r16 (HIGH_ACCUM) ascii code to display
; @modifies r0 (A), r1, r2, r3, r16 (HIGH_ACCUM), r17, Y, Z
draw_char:
; Glyph's first byte is at:
; glyph_pointer = font_starting_mem_pos + (ascii_code * number_of_bytes_per_font)
@ -22,13 +22,13 @@ draw_char:
mov r3, YH
; Load first glyph position on Z
ldi ZH, high(FONT)
ldi ZL, low(FONT)
; Obtain offset multiplying ascii_code * number_of_bytes_per_fontr1
ldi HIGH_ACCUM, FONT_HEIGHT
mul A, HIGH_ACCUM ; result overwrites r0 and r1!
ldi ZH, high(FONT<<1)
ldi ZL, low(FONT<<1)
; Obtain offset multiplying ascii_code * number_of_bytes_per_font
ldi r17, FONT_HEIGHT
mul HIGH_ACCUM, r17 ; result overwrites r0 and r1!
; 16-bit addition between gliph's first byte position and offset (and store result in Z)
add ZL, A
add ZL, r0
adc ZH, r1
; Z contain our glyph's first byte position: draw it
; The drawing consist of FONT_HEIGHT cycles. Every glyph byte is placed on its own line
@ -49,3 +49,11 @@ draw_char:
mov YH, r3
adiw YH:YL,1 ; just increment pre-char-drawing-saved chunk cursor position by 1
ret
; Sets the cursor to 0,0 and clears fine position
cursor_pos_home:
; Set Y to framebuffer start
ldi YH, high(FRAMEBUFFER)
ldi YL, low(FRAMEBUFFER)
clr POS_FINE
ret

View File

@ -31,10 +31,3 @@ comm_init:
brne comm_wait_byte ; if not 0, repeat h_picture_loop
jmp comm_init ; filled all memory: reset framebuffer position
; Sets the cursor to 0,0 and clears fine position
cursor_pos_home:
; Set Y to framebuffer start
ldi YH, high(FRAMEBUFFER<<1)
ldi YL, low(FRAMEBUFFER<<1)
clr POS_FINE
ret

View File

@ -68,29 +68,61 @@ main:
ldi HIGH_ACCUM, 0x00
out DDRB, HIGH_ACCUM ; set port as input (used as data bus)
; clear ram
;*** Load data into ram ***
; Set X to 0x0100
ldi r27, high(FRAMEBUFFER)
ldi r26, low(FRAMEBUFFER)
load_mem_loop:
clr r17
st X+, r17
; if reached the last framebuffer byte, exit cycle
cpi r27, 0b00111110
brne load_mem_loop ; if not 0, repeat h_picture_loop
cpi r26, 0b11000000
brne load_mem_loop ; if not 0, repeat h_picture_loop
; test draw character routine
ser r17
test_draw_loop:
ldi r16, 'P'
mov A, HIGH_ACCUM
call draw_char
ldi HIGH_ACCUM, 'A'
mov A, HIGH_ACCUM
call draw_char
ldi HIGH_ACCUM, 'T'
mov A, HIGH_ACCUM
call draw_char
ldi HIGH_ACCUM, '8'
mov A, HIGH_ACCUM
call draw_char
ldi HIGH_ACCUM, '0'
mov A, HIGH_ACCUM
call draw_char
ldi HIGH_ACCUM, ' '
mov A, HIGH_ACCUM
call draw_char
dec r17
breq test_draw_loop
;call cursor_pos_home
ldi HIGH_ACCUM, 'P'
call draw_char
ldi HIGH_ACCUM, 'A'
call draw_char
ldi HIGH_ACCUM, 'T'
call draw_char
ldi HIGH_ACCUM, '8'
call draw_char
ldi HIGH_ACCUM, '0'
call draw_char
ldi HIGH_ACCUM, ' '
call draw_char
ldi HIGH_ACCUM, 'H'
call draw_char
ldi HIGH_ACCUM, 'o'
call draw_char
ldi HIGH_ACCUM, 'm'
call draw_char
ldi HIGH_ACCUM, 'e'
call draw_char
ldi HIGH_ACCUM, ' '
call draw_char
ldi HIGH_ACCUM, 'c'
call draw_char
ldi HIGH_ACCUM, 'o'
call draw_char
ldi HIGH_ACCUM, 'm'
call draw_char
ldi HIGH_ACCUM, 'p'
call draw_char
ldi HIGH_ACCUM, 'u'
call draw_char
ldi HIGH_ACCUM, 't'
call draw_char
ldi HIGH_ACCUM, 'e'
call draw_char
ldi HIGH_ACCUM, 'r'
call draw_char
; *** timer setup (use 16-bit counter TC1) ***
@ -109,7 +141,7 @@ main:
; Timer setup completed.
; Wait for data (it never exits)
jmp comm_init
;jmp comm_init
forever:
jmp forever