;; uint16_t * input;
        ;; uint8_t * input_len = 0;
        ;; uint16_t * input_j = 2;
        ;; uint16_t * input_k = 4;
        ;; uint8_t * k_index = 1;
                BRA r :reset    ; RESB
                NOP i           ; IRQB

                ;; reset stack
reset:          LDX # ff
                TXS i

                ;; *input_k = input
                LDA # :_bin_aoc/2020/day1/input_start_l
                STA zp 4
                LDA # :_bin_aoc/2020/day1/input_start_h
                STA zp 5

                ;; *input_len = _bin_aoc/2020/day1/input_size / 2
                LDA # :_bin_aoc/2020/day1/input_size_h
                LSR A
                LDA # :_bin_aoc/2020/day1/input_size_l
                ROR A
                STA zp 0

                ;; *k_index = *input_len
                STA zp 1


_day1_loopx:    LDA # :_bin_aoc/2020/day1/input_start_l    ;;
                STA zp 2                     ;;
                LDA # :_bin_aoc/2020/day1/input_start_h    ;;
                STA zp 3                     ;; *input_j = input
                LDA zp 0                     ;; (input_size)
                TAX i                        ;; X = *input_len

_day1_loop:     CLC i         ;; /* 16-bit addition+comparison (lower byte) */
                LDY # 0       ;;
                LDA (zp),y 2  ;;
                ADC (zp),y 4  ;; A = ((uint8_t *)(*input_j))[0] + ((uint8_t *)(*input_k))[0]
                PHP s         ;;
                CMP # e4      ;;
                BNE r :_day1_next  ;; if (A != 0xE4) goto _next

                PLP s         ;; /* 16-bit addition+comparison (upper byte) */
                LDY # 1       ;;
                LDA (zp),y 2  ;;
                ADC (zp),y 4  ;; A = ((uint8_t *)(*input_j))[1] + ((uint8_t *)(*input_k))[1]
                CMP # 07      ;;
                BEQ r :_day1_found ;; if (A == 0x07) goto _found

_day1_next:     CLC i         ;;
                LDA zp 2      ;;
                ADC # 2       ;;
                STA zp 2      ;;
                LDA zp 3      ;;
                ADC # 0       ;;
                STA zp 3      ;; *input_j = *input_j + 2
                DEX i         ;;
                BNE r :_day1_loop  ;; if (--X != 0) goto _loop

                CLC i         ;;
                LDA zp 4      ;;
                ADC # 2       ;;
                STA zp 4      ;;
                LDA zp 5      ;;
                ADC # 0       ;;
                STA zp 5      ;; *input_k = *input_k + 2
                LDY zp 1      ;;
                DEY i         ;;
                STY zp 1      ;; *k_index = k_index - 1;
                BNE r :_day1_loopx ;; if (*k_index != 0) goto _loopx

_day1_notfound: BRA r :_day1_notfound

_day1_found:    LDX # 8
                LDY # 0       ;; copy **input_j and **input_k to mul24 `a` and `b` arguments
                LDA (zp),y 2  ;;
                STA zp,x 0    ;;
                LDA (zp),y 4  ;;
                STA zp,x 3    ;;
                              ;;
                LDY # 1       ;;
                LDA (zp),y 2  ;;
                STA zp,x 1    ;;
                LDA (zp),y 4  ;;
                STA zp,x 4    ;;
                              ;;
                LDA # 0       ;;
                STA zp,x 2    ;;
                STA zp,x 5    ;;

                JSR a :mul24

                JSR a :lcd_reset

                LDX # 10
                LDY # 3
                JSR a :lcd_hex

_day1_stop:     BRA r :_day1_stop