Subversion Repositories copyblaze

; this programm calculate the sum of the "value" 16bit.

; value = 5; total = 5 + 3 + 2 + 1 = 15

; the result is 16bit outputed

                CONSTANT        WAVEFORM_PORT, 02

                CONSTANT        COUNTER_PORT, 04

                NAMEREG s0, total_low

                NAMEREG s1, total_high

                NAMEREG s8, value

start:

                LOAD    value           ,       1F                              ; find sum of all values to 31

                LOAD    total_low       ,       00                              ; clear 16-bit total

                LOAD    total_high      ,       00                              ;

                CALL    sum_to_value                                    ; calculate sum of all numbers up to value

                OUTPUT  total_high      ,       COUNTER_PORT    ; Result will be 496 (01F0)hex

                OUTPUT  total_low       ,       WAVEFORM_PORT   ;

end:

                JUMP    end

                ;

                ; Subroutine called recursively

sum_to_value:

                ADD             total_low       ,       value                   ; perform 16-bit addition

                ADDCY   total_high      ,       00

                SUB             value           ,       01                              ; reduce if down to zero

                RETURN  Z                                                               ; finished if down to zero

                CALL    sum_to_value                                    ; recursively call of subroutine

                RETURN                                                                  ; finished !