Re: RP2350 and Pico 2 - things missing

On 01/09/2024 11:53, Ahem A Rivet's Shot wrote:

On Sun, 1 Sep 2024 11:07:17 +0100
mm0fmf <none@invalid.com> wrote:
 

On 01/09/2024 08:50, Lawrence D'Oliveiro wrote:

On Thu, 29 Aug 2024 21:33:28 +0100, druck wrote:
>

Yes stdint.h is your friend

>
Unless you have an elderly code base that still hasn’t caught up with
C99 ...

>
Or you were programming in C on an Analog Devices SHARC were char was 32
bits.

  I'll bet that broke a lot of bad code :)
  Stll even in that environment a compliant compiler should still
provide int<n>_t types. They'd probably have to have horrendously
inefficient implementations not dissimilar to the bitfields in structs but
they should exist. Woe betide anyone who thought they could put a char into
an int16_t safely though.
 

ISTR the compiler was a custom version of gcc 1.xx. 26 years ago so the exact version has evaporated from my memory. The compiler did understand the hardware funnies well, floats were 32bits or 40bits, it understood the zero overhead loops and circular buffer support. But all the fixed point multiply and accumulate stuff we did in inline assembler. All the performance stuff was in hand optimised assembler as you could do a DMA in, integer operation, multiply&accumulate, float operation and a DMA out all the in one cycle. There was dual access on chip RAM too, you could read and then write the same location in the same clock cycle.
Careful programming meant you could get quite amazing levels of DSP processing run on what was only a 66MHz device.