Lpc2000

On Saturday 27 August 2005 00:46, y4krys wrote:
> What is the mode your compiler is set to?  In THUMB mode all data
> must be 16 bits long.  ARM can add shifts to load some 32-bit values
> to registers, but not always.

There is an often-spouted fallacy that Thumb mode is like x86 16-bit mode with 
16-bit data/registers. This is not so.

Thumb is only a 16-bit encoding of a subset of the the ARM instructions. The 
Thumb instructions are effectively decoded in hardware (no overhead) to 
generate an underlying ARM instruction.

Thumb instructions still process data as 32-bit entities using 32-bit 
registers, using 32-bit literal pools etc.

The only difference as far as data handling is concerned is that Thumb has a 
reduced number of bits, so the values handled by mov immediate instructions 
is limited.