[sdiy] Some Audio DSP prototypes

Neil Johnson neil.johnson71 at gmail.com
Wed Apr 20 14:10:22 CEST 2022

Ingo Debus wrote:
> On my day job, I had written programs for the 8051 (only 256 bytes of RAM! Certainly not more powerful than a PIC) in C for many years. In fact, C can be easier on RAM than assembly language, since in assembly there’s no such thing as local variables.
> And regarding program memory usage: in the beginning I tried to outsmart the compiler (counting a loop counter down rather than up), hoping the compiler would use the DJNZ instruction. DJNZ (decrement and jump if not zero) is a powerful 8051 instruction for creating loops. Then I looked at the code the compiler had created: no DJNZ in there. Looking closer I found that the compiler’s solution was shorter and faster than the one I had in mind.

I also started using microcontrollers with the 8051 (in my case the
87C751).  The Keil C51 compiler was simply amazing and I spent days
looking at the assembler code it generated to understand HOW it could
do it.  It's partly what got me interested in compiler technology...
which led to jobs, a PhD, more jobs......
The 8051 ICE, with the bondout chips, was also fun to use if somewhat
clunky, and thick cables to the debug pod :(


More information about the Synth-diy mailing list