; -*-asm-*-
include(`common.m4')

        BRA r :reset ; RESB
        NOP i        ; IRQ

        ;; reset stack
reset:  LDX # ff
        TXS i

        ;; Set pins 0-4 on Port A to Output
        LDA # %00011111
        STA a DDRA

        ;; Display ON/OFF:
        ;;  D7  D6  D5  D4  D3  D2  D1  D0
        ;;   0   0   1   1   1   1   1   D
        ;;
        LDA # %00111111
        JSR a :lcd-w-rs0-c2
        LDA # %00111111
        JSR a :lcd-w-rs0-c1

        JSR a :reset-oled

        LDA # 0                 ; face address
        STA zp 0
        LDX # 1                 ; X page

_face_page:     LDA # %01000000 ; Y address
                JSR a :lcd-w-rs0-c2

                TXA i
                ORA # %10111000 ; X page
                JSR a :lcd-w-rs0-c2
                TXA i
                ORA # %10111000 ; X page
                JSR a :lcd-w-rs0-c1

                PHX s
                LDY # 17        ; Y address
                LDX zp 0
_face_fill:     LDA a,x :_bin_face_start
                JSR a :lcd-w-rs1-c2

                TYA i
                CLC i
                ADC # 28
                ORA # %01000000 ; Y address
                JSR a :lcd-w-rs0-c1

                LDA a,x :_bin_face_start
                JSR a :lcd-w-rs1-c1

                INX i
                STX zp 0

                DEY i
                CPY # 0
                BPL r :_face_fill ; BGE 0

                PLX s
                INX i
                CPX # 7
                BNE r :_face_page

stop:   JMP a :stop


reset-oled:     LDY # 00

                LDA # %01000000 ; Y address
                JSR a :lcd-w-rs0-c2

_next_page:     TYA i
                ORA # %10111000 ; X page
                JSR a :lcd-w-rs0-c2

                TYA i
                ORA # %10111000 ; X page
                JSR a :lcd-w-rs0-c1

                LDX # 40
_fill_page:     LDA # 00
                JSR a :lcd-w-rs1-c2

                TXA i
                SEC i
                SBC # 1
                ORA # %01000000 ; Y address
                JSR a :lcd-w-rs0-c1

                LDA # 00
                JSR a :lcd-w-rs1-c1
                DEX i
                BNE r :_fill_page

                INY i
                CPY # 8
                BNE r :_next_page

                RTS s

        ;; write "instruction"
lcd-w-rs0-c2:   JSR a :lcd-wait-c2

                STA a PORTB
                LDA # hh(G_C2)
                STA a PORTA
                LDA # hh(G_C2|G_E)
                STA a PORTA
                LDA # hh(G_C2)
                STA a PORTA

                RTS s

lcd-w-rs0-c1:   JSR a :lcd-wait-c1

                STA a PORTB
                LDA # hh(G_C1)
                STA a PORTA
                LDA # hh(G_C1|G_E)
                STA a PORTA
                LDA # hh(G_C1)
                STA a PORTA

                RTS s

        ;; write "data" to lcd
lcd-w-rs1-c2:   JSR a :lcd-wait-c2

                STA a PORTB
                LDA # hh(G_RS|G_C2)
                STA a PORTA
                LDA # hh(G_RS|G_C2|G_E)
                STA a PORTA
                LDA # hh(G_RS|G_C2)
                STA a PORTA

                RTS s

lcd-w-rs1-c1:   JSR a :lcd-wait-c1

                STA a PORTB
                LDA # hh(G_RS|G_C1)
                STA a PORTA
                LDA # hh(G_RS|G_C1|G_E)
                STA a PORTA
                LDA # hh(G_RS|G_C1)
                STA a PORTA

                RTS s

        ;; wait BF
lcd-wait-c2:    PHA s

                LDA # %00000000  ;; Set pins 0-7 on Port B to Input
                STA a DDRB

_lcd_wait-c2:   LDA # hh(G_RW|G_C2)
                STA a PORTA
                LDA # hh(G_RW|G_C2|G_E)
                STA a PORTA
                LDA a PORTB
                AND # %10000000
                BNE r :_lcd_wait-c2

                LDA # hh(G_RW|G_C2)
                STA a PORTA

                LDA # %11111111  ;; Set pins 0-7 on Port B to Output
                STA a DDRB

                PLA s
                RTS s

        ;; wait BF
lcd-wait-c1:    PHA s

                LDA # %00000000  ;; Set pins 0-7 on Port B to Input
                STA a DDRB

_lcd_wait-c1:   LDA # hh(G_RW|G_C1)
                STA a PORTA
                LDA # hh(G_RW|G_C1|G_E)
                STA a PORTA
                LDA a PORTB
                AND # %10000000
                BNE r :_lcd_wait-c1

                LDA # hh(G_RW|G_C1)
                STA a PORTA

                LDA # %11111111  ;; Set pins 0-7 on Port B to Output
                STA a DDRB

                PLA s
                RTS s