#307 Smaller code by bit to bit transfer on PIC14 port

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nobody
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5
2010-12-02
2010-12-02
Gál Zsolt
No

SDCC is a good help for me. Time to time I check the code generated by the SDCC. I didn't think before, that the bit transfer between to file registers is requires so many steps. I counted it and the number is 23 steps. I am sure, that I don't use the ideal code for it, but my soultion is using less steps. SDCC is using a template register betwen reading the bit from input, and writing it to the output. I would like to ask for changing it. Not using a general template register.
To avoid a lot of BANKSEL macro, I propose to use STATUS register bits during the transfer if it is possible.
For example moving Porta.0 bits into a flag.0 bits in 11 steps:

2 BANKSEL _PORTA_bits
3 BCF STATUS,0
4 BTFSC _PORTA_bits,0
5 BSF STATUS,0
7 BANKSEL _flags
8 BTFSS STATUS,0 ; This line needs for not doing more then 1 change on the output
9 BCF _flags,0
10 BTFSC STATUS,0
11 BSF _flags,0

Additionally this solution doesn't use GOTO.

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