What is the difference between instruction prefetch and instruction pipelining in arm7tdmi?

sorry it was my typing mistake it was prefetching not prefacing

sorry it was my typing mistake it was prefetching not prefacing

Hello ineev,

I think you would say about the software pipelining by the word of "instruction pipelining".
If you would say about the prefetch instruction by the word of the "instruction prefetch" instead of the prefetching of instructions, it might be a subset concept of the software pipelining.
Please assume the following procedure.

for(i=0;i<N;i++){
  Proc_A(i);
  Proc_B(i);
}

Here, Proc_B(i) has the dependency with Proc_A(i), and Proc_B(i) can start after the execution of Proc_A(i).

In this case, by the re-ordering of the procedures like as the following, the dependency might be resolved.

for(i=0;i<(N/2); i+=2){
  Proc_A(i);
  Proc_A(i+1);
  Porc_B(i);
  Proc_B(i+1);
}

This is the software pipelining.
On the other hands, the prefetch instruction is related to the data cache.
By putting the data which will be handled in the future into the data cache in advance, the data can be used without delay of the data fetching from an external memory as the following.
[1] before

for(i=0;i<N;i++){
  Memory_B[i] = Memmory_A[i];
}

[2] after

for(i=0;i<N;i++){
  Prefetch_into_DCache(Memory_A[i+1]); // By using PLD instruction
  Memory_B[i] = Memmory_A[i];
}

This would be a kind of the software pipelining.

By the way, the instruction prefetching is related to the hardware of the core.
It means to prefetch the next instructions in advance, while executing the current instruction, in order to decode them without memory delays.
This would have nothing to do with the software pipelining.
However, the concept might be like the prefetch instruction.

HTH,
Best regards,
Yasuhiko Koumoto.