On 2/26/07, Joerg Wunsch <[EMAIL PROTECTED]> wrote:
David McNab <[EMAIL PROTECTED]> wrote:
> The code in /doc/examples/asmdemo in the avr-libc tree is only
> limited value, because all the assembler code seems to be just ISRs,
> with no calling between C and assembler.
Sorry, I simply couldn't fit anything into it like that that would
serve as a useful example (i.e. something where diverting to asm was
really justified). The example is supposed to be a real-world one,
nothing artificial.
Multiplying a 16-bit number by an 8-bit number to produce a 24-bit
result is a good example of something that GCC does not yet do and can
only be accomplished in assembler. GCC will multiply a 32-bit number
by a 32-bit number to produce a 32-bit result, but that takes many
more multiply instructions than necessary. This multiplication topic
was discussed on this mailing list previously.
Cheers,
Shaun
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