[fpc-pascal] Reversing bit-order of byte

Koenraad Lelong fpascal at brouwerij.homelinux.net
Thu May 3 09:10:40 CEST 2012


I'm porting a driver, originally written in C, for an LCD to be used 
with an embedded arm-processor (STM32).
The original driver uses SPI, my driver will use a USART in synchronous 
mode because the STM32 has no SPI for 9-bit. Unfortunately, the 
bit-order is reversed between SPI and USART transmission.
Does anyone knows an efficient way to reverse bit-order of a byte for 
the arm-processor ? I'm going to look into the assembly language of the 
arm-processor, but maybe someone knows this immediately.
For old processors like 8085 or Z80 I know how to do this, but 
arm-assembler is new to me.

Thanks for any hints.

Koenraad Lelong.

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