Here's one:

Code:
ticksnd:
@ movlw     0x01                        'set sound duration for intro
@ movwf     _sbyte                        '
@ movlw     0x1B                        'set sound step value for intro
@ movwf     _soundcalc                    'soundcalc = $1B
@ movlw     0xFF                        'set the start frequency
@ movwf     _sbuff                        '
xcr:
@ movf         _soundcalc     ,W                'calc the next sound
@ addwf     _sbuff     ,F                    '
@ call         _audo                        'make sound
@ decf         _sbuff    ,F                    '
@ incfsz     _sbuff    ,F                    '
@ goto         _xcr                        'check for exit blast routine
@ return                                'exit when sound is finished
audo:
SOUND portc.7,[sbuff,sbyte]                'output sound
@ return
'
Just gosub ticksnd.

Anyone got any others to share?