penguin86/pato-z80-home-computer
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

WIP newline and end-of-screen shift

Browse Source
This commit is contained in:
Daniele Verducci su MatissePenguin
2021-02-15 22:54:54 +01:00
parent d3604ca3ab
commit e34cfef259
3 changed files with 57 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

60
pat80-io-devices/composite-pal-adapter/software/avr-assembly/character_generator.asm
View File

@@ -56,16 +56,19 @@ draw_char:
adiw YH:YL,1 ; just increment pre-char-drawing-saved chunk cursor position by 1
ret
draw_char_eol:
; Check if end of screen
cpi YH, high(FRAMEBUFFER_END)
brne draw_char_end
cpi YL, low(FRAMEBUFFER_END)
brne draw_char_end
; End of screen reached! Scroll framebuffer by 1 line
call scroll_screen
ret
draw_char_end:
; end of line
clr POS_COLUMN ; reset column to 0
adiw YH:YL,1 ; increment chunk cursor position by 1 (begin of next line on screen)
; Check if end of screen
cpi YH, high(FRAMEBUFFER_END + 1)
brne draw_char_end
cpi YL, low(FRAMEBUFFER_END + 1)
brne draw_char_end
; End of screen reached! Scroll framebuffer by 1 line (=46*FONT_HEIGHT bytes)
; TODO
draw_char_end:
ret
; Sets the cursor to 0,0 and clears fine position
@@ -102,6 +105,47 @@ set_framebuffer_pointer_to_text_cursor:
; Moves cursor to start of following screen line
; Takes care of particular cases, i.e. end of screen (shifts all screen up by one line)
draw_carriage_return:
; Set memory pointer to start of line
sub YL, POS_COLUMN
sbci YH, 0
; Set cursor to start of current line
subi POS_COLUMN, LINE_COLUMNS
; Go to next line
ldi HIGH_ACCUM, high(LINE_COLUMNS*FONT_HEIGHT)
add YH, HIGH_ACCUM
ldi HIGH_ACCUM, low(LINE_COLUMNS*FONT_HEIGHT)
adc YL, HIGH_ACCUM
ret
; Scrolls the screen by one line (=LINE_COLUMNS*FONT_HEIGHT bytes)
; and clears the last line (FRAMEBUFFER_END - LINE_COLUMNS*FONT_HEIGHT bytes)
scroll_screen:
clr POS_COLUMN ; cursor to first column
; "Read" Pointer to first char of second line
ldi YH, high(FRAMEBUFFER+LINE_COLUMNS*FONT_HEIGHT)
ldi YL, low(FRAMEBUFFER+LINE_COLUMNS*FONT_HEIGHT)
; "Write" Pointer to first char of first line
ldi XH, high(FRAMEBUFFER+LINE_COLUMNS*FONT_HEIGHT)
ldi XL, low(FRAMEBUFFER+LINE_COLUMNS*FONT_HEIGHT)
; Copy data
scroll_screen_copy_loop:
ld A, Y+
st Z+, A
cpi r31, high(FRAMEBUFFER_END-LINE_COLUMNS*FONT_HEIGHT)
brne scroll_screen_copy_loop
cpi r30, low(FRAMEBUFFER_END-LINE_COLUMNS*FONT_HEIGHT)
brne scroll_screen_copy_loop
; All the lines have been "shifted" up by one line.
; The first line is lost and the last is duplicate. Clear the last.
clr A
scroll_screen_clear_loop:
st Z+, A
cpi r31, high(FRAMEBUFFER_END)
brne scroll_screen_clear_loop
cpi r30, low(FRAMEBUFFER_END)
brne scroll_screen_clear_loop
; Last line cleared. Leave cursor pointer to last line start
ldi YH, high(FRAMEBUFFER_END-LINE_COLUMNS*FONT_HEIGHT)
ldi YL, low(FRAMEBUFFER_END-LINE_COLUMNS*FONT_HEIGHT)
ret