rotate bytes in array

[LinkMTech]

Guys,
May not be the solution for Art's project, but this post interested me because I was also stumped trying to shift bytes of data FIFO and ended up making something work for me.
I liked the FOR/NEXT approach given here and thought I would try it since it looked faster and smaller since I'm really collecting 32 bytes instead of 12 in this example.

My kludge: This scheme uses 24 words and takes 12.5us

DEFINE OSC 8

RX      VAR BYTE        ' Buffer data
XYZ_val VAR BYTE[12]    ' Accelerometer XYZ data
TC_OUT  VAR PORTC.4     ' Test point to measure loop time

Load_array:
TC_OUT = 1
    XYZ_val[0] = XYZ_val[1]     ' Oldest data
    XYZ_val[1] = XYZ_val[2]
    XYZ_val[2] = XYZ_val[3]
    XYZ_val[3] = XYZ_val[4]
    XYZ_val[4] = XYZ_val[5]
    XYZ_val[5] = XYZ_val[6]
    XYZ_val[6] = XYZ_val[7]
    XYZ_val[7] = XYZ_val[8]
    XYZ_val[8] = XYZ_val[9]
    XYZ_val[9] = XYZ_val[10]
    XYZ_val[10] = XYZ_val[11]
    XYZ_val[11] = RX            ' Newest data
TC_OUT = 0    
RETURN

Was surprised to to find that this scheme uses 43 words and takes 216us:

DEFINE OSC 8

RX      VAR BYTE        ' Buffer data
XYZ_val VAR BYTE[12]    ' Accelerometer XYZ data
TC_OUT  VAR PORTC.4     ' Test point to measure loop time


Load_array:
TC_OUT = 1
    FOR z = 0 to 10
        XYZ_val[Z] = XYZ_val[Z+1]
    NEXT z
    XYZ_val[11] = RX
TC_OUT = 0
   
RETURN

It meant more typing but saved some space and time.