;------------------------------------------------------------------------ ; ; DICE.ASM ; ; Author: San Bergmans ; www.sbprojects.com ; ; Created for the 6802 Nano Computer at 29-8-1993 ; ; Demonstration program, rolling two dice ; ;------------------------------------------------------------------------ .CR 6800 Select cross overlay .OR $F000 .TF DICE.HEX,INT Specify target file ;------------------------------------------------------------------------ ; Declaration of constants ;------------------------------------------------------------------------ DIE1 .EQ $0000 Roll of die 1 DIE1_FLAG .EQ $0001 Die 1 rolling if <> 0 WALK_PAT1 .EQ $0003 Walking pattern for die 1 DIE2 .EQ $0004 Roll of die 2 DIE2_FLAG .EQ $0005 Die 2 rolling if <> 0 WALK_PAT2 .EQ $0006 Walking pattern for die 2 WALK .EQ $0007,$0008 Walk delay counter POINTER .EQ $0009,$000A Pointer to retreive LED pattern PIA_A .EQ $0080 Pia data register A (die 1) PIA_B .EQ $0081 Pia data register B (die 2) CON_A .EQ $0082 Pia control register A CON_B .EQ $0083 Pia control register B WALK_DELAY .EQ 500 Delay time reload value ;------------------------------------------------------------------------ ; Reset and initialisation ;------------------------------------------------------------------------ RESET LDS #$007F Reset stack pointer LDAA #%0000.0100 Initialise PIA ports STAA CON_A STAA CON_B LDAA #%0111.1111 b0..b6 are outputs b7 is input STAA PIA_A for both PIA ports STAA PIA_B CLRB STAB CON_A STAB CON_B STAA PIA_A STAA PIA_B LDAA #%0000.0100 Select data registers again STAA CON_A STAA CON_B LDX #WALK_DELAY Setup walk delay time STX WALK STAB DIE1 Initialise dice STAB DIE1_FLAG STAB DIE2 STAB DIE2_FLAG LDAA #%0000.0010 Initialise walking light pattern STAA WALK_PAT1 LDAA #%0100.0000 STAA WALK_PAT2 ;------------------------------------------------------------------------ ; Main program loop ;------------------------------------------------------------------------ MAIN BSR SHOW_DICE Show both dice on LEDs CLRB In case push button A not down LDAA PIA_A See if push button A is down BMI .A_NOT_DOWN It's not down! DEC DIE1 Decrement die counter BPL .DIE1_OK Die is within 5..0! LDAA #5 Restart die counter STAA DIE1 .DIE1_OK LDAB #-1 Indicate push button A is down .A_NOT_DOWN STAB DIE1_FLAG Indicate push button A state CLRB In case push button B not down LDAA PIA_B See if push button B is down BMI .B_NOT_DOWN It's not down! DEC DIE2 Decrement die counter BPL .DIE2_OK Die is within 5..0! LDAA #11 Restart die counter (rolls at STAA DIE2 half the speed of die 1) .DIE2_OK LDAB #-1 Indicate push button B is down .B_NOT_DOWN STAB DIE2_FLAG Indicate push button B state BRA MAIN Return to main routine ;------------------------------------------------------------------------ ; Show both dice on the LEDs ;------------------------------------------------------------------------ SHOW_DICE LDX WALK Decrement walking light counter DEX BNE .NO_WRAP No wrap around is needed! LDX #WALK_DELAY Restart counter LDAA WALK_PAT1 Increment walking pattern ASLA for die 1 BPL .WALK_OK1 Not beyond LED 6! LDAA #%0000.0010 Restart walking pattern .WALK_OK1 STAA WALK_PAT1 LDAA WALK_PAT2 Increment walking pattern for LSRA die 2 (the other way around) BITA #%0000.0001 Not before LED 1? BEQ .WALK_OK2 No! O.K. LDAA #%0100.0000 Restart at LED 6 again .WALK_OK2 STAA WALK_PAT2 .NO_WRAP STX WALK LDAA DIE1_FLAG Is die 1 rolling? BNE .DIE1_ROLL Yes! LDAA DIE1 Get die pattern from table BSR GET_PATTERN STAA PIA_A and show it BRA .DIE2 Handle die 2 now! .DIE1_ROLL LDAA WALK_PAT1 Just display walking pattern COMA STAA PIA_A .DIE2 LDAA DIE2_FLAG Is die 2 rolling? BNE .DIE2_ROLL Yes! LDAA DIE2 Get die pattern from table LSRA (Die 2 rolls slower!) BSR GET_PATTERN STAA PIA_B and show it RTS .DIE2_ROLL LDAA WALK_PAT2 Just display walking pattern COMA STAA PIA_B RTS ;------------------------------------------------------------------------ ; Get LED pattern from pattern table ;------------------------------------------------------------------------ GET_PATTERN ADDA #DIE_PAT Add die roll to base address of STAA POINTER+1 the pattern table LDAA /DIE_PAT STAA POINTER LDX POINTER Then use it as index LDAA 0,X to get the actual pattern RTS DIE_PAT .DA #%1111.1110 1 6 1 .DA #%1110.1101 2 .DA #%1110.1100 3 5 0 2 .DA #%1010.0101 4 .DA #%1010.0100 5 4 3 .DA #%1000.0001 6 ;------------------------------------------------------------------------ ; Interrupt and reset vectors ;------------------------------------------------------------------------ .NO $FFF8,$FF .DA RESET IRQ (Not used) .DA RESET SWI (Not used) .DA RESET NMI (Not used) .DA RESET Reset .LI OFF