Hello

The following is a code snip for I2C between a BS2 and another device. I am
new at this and trying to understand the code. It is not commented. I was
hoping someone could explain how this works. It seems to me it would be more
effective to use the shiftin/shiftout command? I am really having trouble with
the :

IF (bit_count & in_byte) then si2c_wbyte_do1

 The "in_byte" is the value we want to write, but it is the "bit_count" that
is shifted to the right. Does this previous command mask the two variables and
"bit_count" is now the sum of those two variables after the mask?

Can someone make this code more efficient?

Help

si2c_wbyte:             ' returns 1 if successful, 0 = NACK
                        ' in_byte is byte to be written
    bit_count=%10000000
    si2c_wbyte_lp:
        low si2c_clk
        input si2c_data
        IF (bit_count & in_byte) then si2c_wbyte_do1
            low si2c_data
        si2c_wbyte_do1:
        bit_count=bit_count>>1
        input si2c_clk
        IF bit_count then si2c_wbyte_lp

    ' now test the acknowlege bit
    low si2c_clk
    input si2c_data
    input si2c_clk
    exit_ack=0
    IF in1 then si2c_wbyte_ex
        exit_ack=1
    si2c_wbyte_ex:
    return