Files
aqhomecontrol/avr/modules/lcd2/font/font8x8.asm
2025-06-02 21:13:44 +02:00

109 lines
2.6 KiB
NASM

; ***************************************************************************
; copyright : (C) 2025 by Martin Preuss
; email : martin@libchipcard.de
;
; ***************************************************************************
; * This file is part of the project "AqHome". *
; * Please see toplevel file COPYING of that project for license details. *
; ***************************************************************************
; ***************************************************************************
; code
.cseg
; ---------------------------------------------------------------------------
; @routine font8x8MonoHandlerFn
;
; Handler for 8x8 Mono Fonts
;
font8x8MonoHandlerFn:
cpi r23, FONT_FN_RENDER
breq font8x8MonoRenderCharacter
rjmp FONT_GenericHandler
; @end
; ---------------------------------------------------------------------------
; @routine font8x8RenderCharacter
; @param R16 character to write
; @param R1:R0 background color
; @param R3:R2 foreground color
; @param Z pointer to font
; @param X pointer to RAM to store data to
; @param r18 char width in pixel
; @param r19 char height in pixel
; @clobbers r17, r24, r25, x
font8x8MonoRenderCharacter:
push zl
push zh
rcall font8x8GetCharPosInFont8x8 ; (r17, r24, r25, z)
ldi r25, 8 ; 8 bytes
font8x8MonoRenderCharacter_loop1:
ldi r24, 8 ; 8 bits
lpm r17, Z+
font8x8MonoRenderCharacter_loop2:
lsr r17
brcs font8x8MonoRenderCharacter_writeForeground
st X+, r0
st X+, r1
rjmp font8x8MonoRenderCharacter_loop2end
font8x8MonoRenderCharacter_writeForeground:
st X+, r2
st X+, r3
font8x8MonoRenderCharacter_loop2end:
dec r24
brne font8x8MonoRenderCharacter_loop2
dec r25
brne font8x8MonoRenderCharacter_loop1
ldi r18, 8
ldi r19, 8
pop zh
pop zl
ret
; @end
; ---------------------------------------------------------------------------
; @routine font8x8GetCharPosInFont8x8
; @param R16 character to write
; @param Z pointer to font
; @return Z pointer to begin of char data
; @clobbers r17, r24, r25, z
font8x8GetCharPosInFont8x8:
mov r24, r16
adiw zh:zl, FONT_OFFS_FIRSTCHAR
lpm r24, Z+ ; first char num
lpm r25, Z+ ; num of chars
sub r16, r24
brcs font8x8GetCharPosInFont8x8_ret
cp r16, r25
brcc font8x8GetCharPosInFont8x8_ret
mov r24, r16
clr r25
lsl r24 ; x2
rol r25
lsl r24 ; x4
rol r25
lsl r24 ; x8
rol r25
add zl, r24
adc zh, r25
font8x8GetCharPosInFont8x8_ret:
ret
; @end