What's the fastest way to...

CannibalRobotics

What's the fastest way to set the Z or C flag in assembly? I'm using the following to toggle a clock line but it's taking too long when you couple it with the cycle overhead of the CALL statement.

'-------------------------------------------------------------------------------------------
CL_ON                   MOV     s,#0                    ' 
                        TEST    s,#0                wz  ' Sets Z flag to 1
                        muxz    dirA,CL_Mask            ' Set CL to 1
                        muxz    OUTA,CL_Mask            ' Set CL to 1   
CL_ON_Ret               ret
'-------------------------------------------------------------------------------------------
CL_Off                  MOV     s,#0                    ' 
                        TEST    s,#0                wz  ' Sets Z flag to 1
                        muxz    dirA,CL_Mask            ' Set CL to output
                        muxnz   OUTA,CL_Mask            ' Set CL to 0   
CL_Off_Ret              ret
'-------------------------------------------------------------------------------------------

It's imbedded in a driver for an ADC088S052. The usage is this:

                        '.....
                        CALL    #CS_Off                  ' Chip Select Low, wake up ADC
                        CALL    #CL_Off                  ' 3 clock pulses to initiate conversion    
                        CALL    #CL_On                   '   
                        CALL    #CL_Off                  ' 
                        CALL    #CL_On                   '   
                        CALL    #CL_Off                  '                                                 
                         
                        SHR     t2,#2                   ' Shift it right 2 places (MSB out first)
                        AND     t2,#%0_0000_0001 wz wc  ' Test LSB
                        muxz    OUTA,DI_mask            ' Put a 1 on data line
                        muxnz   OUTA,DI_mask            ' Pot a 0 on data line
                         
                        CALL    #CL_On                  ' Clock High
                        
                        MOV     t2,ADChan               ' Get ADChan again 
                        SHR     t2,#1                   ' Shift it right once for middle bit
                        '.....

All these clock calls are driving up the time but I can't seem to figure out a way to directly toggle the port without doing a flag related operation.
Any ideas?

Thanks,
Jim-

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heater

Why do you want to set DIRA all the time? Just do it once at start up.

Use:

or outa, CL_Mask

to set the output high. Use:

andn outa, CL_Mask

to set it low.

Neither of these will upset other bits in outa.

No calls required.

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For me, the past is not over yet.

CJ

OR outa, bitmask to set port bit
ANDN outa, bitmask to clear port bit

bitmask long |< pin 'creates a long that has a single bit high that corresponds to the pin

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